Introduction to Shock

In medical terms, “shock” is a life-threatening condition where blood is being pumped throughout the body at an insufficient level, starving the body of oxygen and nutrients. Shock is actually a result of the body attempting to protect itself from harmful stimuli, such as injury. During this defense response heart rate increases, blood vessels narrow, and the kidney retains water to help maintain blood volume; all in an attempt to maintain appropriate blood supply to the vital organs.

Unfortunately these compensatory measures eventually fail, causing blood pressure to drop to a dangerous level. When this happens, cells become starved for oxygen and enter an anaerobic metabolism stage where high levels of carbon dioxide and lactate is produced. These substances lower the pH of the blood, leading to even more complications. As the condition continues to deteriorate, cell death escalates to cause irreversible damage and even death.

Causes of Shock

Shock is a condition that can be caused by a number of factors that ultimately lead to the same problem; reduced tissue perfusion. Shock can generally be divided into the following classification.

Hypovolemic Shock

Hypovolemic shock is a type of shock that occurs when there is not enough blood volume in the body to adequately perfuse the tissues. Probably the most common type of hypovolemic shock is also called hemorrhagic shock, and results from excessive bleeding as a result of trauma, ulcers, or other conditions that cause blood loss. Hypovolemic shock may also be caused by severe dehydration, where there is not enough water present in the body to maintain blood pressure despite no blood being lost.

Obstructive Shock

Another type of shock is obstructed shock, where tissues are unable to be perfused because of an obstruction that is blocking blood flow, such as a blood clot.

Distributive Shock

In distributive shock, blood simply does not reach where it needs to go due to an abnormal distributive pattern. This unusual occurrence can be caused by a number of factors, including other types of shock.

Cardiogenic Shock

The heart is a critical organ responsible for pumping oxygenated blood throughout the body. During Cardiogenic shock, however, the heart is unable to pump adequate amounts of blood to support tissue function. Cardiogenic shock is most often a result of a heart condition or damage to the heart, such as in the case of a heart attack.

Neurogenic Shock

This type of shock is caused by a loss of communication between the sympathetic nervous system and the blood vessels it controls. Ordinarily the nervous system plays a major role in adjusting the tone of blood vessels in order to control blood pressure. When this connection is lost, the vessels relax and dilate, leading to a dangerous drop in blood pressure. Neurogenic shock is most commonly caused by damage to the spinal cord.

Anaphylactic Shock

Anaphylactic shock is the result of a severe allergic reaction that caused blood vessels to dilate and blood pressure to fall. Additionally, the allergens may also cause excess fluid to be taken up into the tissues, leading to swelling and even lower blood pressure and volume.

Septic Shock

Caused by widespread infection, septic shock can be life threatening if not treated quickly. This infection can result in many small blood clots which block the perfusion to the tissues.

 Signs and Symptoms of Shock

The signs and symptoms of shock become progressively more noticeable as the condition worsen, making detection of early signs important for early intervention.

Early Signs

• Elevated heart rate
• Minimal drop in mean arterial pressure (MAP) ~ 10mmHg

Compensatory Signs

• Further drop in MAP ~ 10 – 15mmHg
• Increased elevated heart rate
• Weak and rapid pulse
• Restlessness
• Fatigue
• Cool, clammy skin

Progressive Signs

• MAP drops ~ 20mmHg from baseline
• Reduced urine output
• Extreme fatigue
• Pale skin
• Bluish discoloration of the nail beds and lips
• Dizziness
• Altered mental status

Refractory Signs

• Unconsciousness
• Cell and organ damage

Clinical Manifestations

The clinical manifestations of shock include a range of signs, symptoms, and tests that can be observed or performed to help identify the condition. Examples of these manifestations include the following.

Physical manifestations

• Reduced alertness
• Heart rate > 100 beats per min
• Respiratory rate > 22 breaths per min
• Systolic Blood pressure <90mmHg, or a ≥30mmHg drop from baseline
• Urine output < 0.5mL/kg/hour

Laboratory manifestations

• Lactate > 3mmol/L, or 27 mg/dL
• PaCO2 < 32mmHg
• Base deficit < −4 mEq/L

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Treatment

Pharmacology of Shock

Treatment of shock generally consists of three categories; Supportive care, IV fluids, and additional treatment needed depending on the specific type of shock.

Supportive care

Supportive care begins by turning the client’s head to the side to avoid aspiration of any vomit that may occur. Warm blankets are placed and oxygen is supplied either a face mask, or intubation if necessary. Catheters are placed to allow access to venous system. Additional monitoring tools are placed in order to monitor blood pressure, heart rate, oxygen saturation, urine output, and more. These tools help the medical team to assess and monitor the condition of the client, allowing them to make more educated decisions on treatment strategy.

Vasopressors (phenylephrine, norepinephrine, epinephrine, and vasopressin, and dopamine) and inotropes (dobutamine and milrinone) are drugs that can be used to rapidly increase blood pressure by way of vasoconstriction. Doses of these drugs may be required during the initial treatment phases of shock. It should be noted that these medications are not a cure, they only allow for a temporarily increase in blood pressure to buy the client time. The ultimate goal when treating shock is to treat the cause and allow the body to restore and maintain blood pressure and tissue perfusion on its own.

IV Fluids

Another hallmark treatment for shock is the administration of IV fluids which are used to restore vascular volume. The typical initial treatment approach is 1L of normal saline infused over a period of 15 minutes. If parameters do not return to normal, additional fluid may be administered.

Additional Treatments

Supportive care and IV fluids are the mainstays of shock treatment, but additional measures may need to be taken depending on the specific type of shock being treated. These additional treatments typically deal with dealing with the source of the shock which varies between types. Perhaps the most obvious example of a necessary additional treatment is in the case of hemorrhagic shock, which results from severe blood loss. In this case, the bleeding event would also need to be promptly addressed alongside the other two measures in order for the shock to be treated. In the case of septic shock caused by widespread infection, broad spectrum antibiotics would also be administered to begin infection treatment.

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Nursing Interventions

Nursing interventions play a critical role in the success or failure of treating clients with shock. In fact, nurses are often the one who initially identify the condition due to their close client contact. It is for this reason that nurses must remain vigilant and well trained to recognize the early signs of shock.

Additionally, many of the methods used to treat shock fall directly to the responsibility of nurses, including fluid administration, monitoring vital signs, catheter placement, oxygen administration, and providing supportive care.

Conclusion

“Shock” is an umbrella term which can be broken down into a number of different subtypes. While each of these subtypes arises from different causes, they share important similarities such as hypotension and inadequate tissue perfusion. Likewise, the treatment of these subtypes also possesses many similarities in addition to a few differences. Whichever type of shock is being treated, however, nurses will undoubtedly be on the front lines.

References

Quick and dirty guide to shock. Medic Tests.
https://legacy.medictests.com/quick-dirty-guide-shock/. Accessed May 25, 2020.

Shock. Merck Manuals. https://www.merckmanuals.com/professional/critical-care-medicine/shock-and-fluid-resuscitation/shock. Accessed May 25, 2020.

Shock. Better Health. https://www.betterhealth.vic.gov.au/health/ConditionsAndTreatments/shock. Accessed May 25, 2020.

Inotropes and Vasopressors. NCBI. https://www.ncbi.nlm.nih.gov/books/NBK482411/. Accessed May 25, 2020.

Introduction to Health Assessment

A major component of nursing responsibilities includes performing health assessments on new or returning clients. A health assessment can be general, encompassing past medical history and a head-to-toe assessment, or can be specific and diseases related, such as assessing for cancers or alcoholism. The assessment you provide as a nurse will vary based on your role and based on the setting in which you practice. A health assessment in general will consist of observations and measurements in order to identify problems or keep the client safe. This Health Assessment NCLEX^® Review aims to provide readers with an understanding of health assessment in order to prepare for daily responsibilities as a nurse as well as the NCLEX^® exam.

Importance of Health Assessment

Health assessments serve the purpose of identifying current problems, identifying problems the client is at risk for, keeping the client alive and/or stable, and treating any current problems. Thorough, accurate health assessments create the pathway for the client’s treatment and care plan. Performing a health assessment requires organization, focus, and competence with each client.

Prior to Starting a Health Assessment

Before you start a health assessment, be sure the room or area is clear, that there are no safety precautions and that you have necessary equipment for the assessment. Equipment may include gloves, thermometer, blood pressure cuff, watch, scale, tape measure, light, stethoscope, among other more specialized tools. A health assessment is driven by the needs of the client.

Head-to-Toe Health Assessment

As you may infer from the name, a head-to-toe health assessment is one that encompasses the entire client from head to toe. This includes physical and neurological health. The head-to-toe assessment includes the client’s mental status, head, neck, thorax, abdomen, and extremities. Throughout the exam, observe the skin for color, lesions, temperature, and dryness or moisture2.

Head-to-toe approach for generic physical assessments

Gather data while moving from head to toe, asking related questions along the way. Though this is a general overview of how to conduct a head-to-toe assessment, each client is unique and may require more investigation into problem areas as the assessment continues.

Health Assessment Pneumonic Tools

It can be overwhelming to remember all of the details that go into performing a thorough health assessment. Pneumonic tools exist for a variety of health assessment components and can help you perform a thorough assessment.

Level of Consciousness Assessment: AVPU4

This assessment tool helps you determine a client’s level of consciousness by assessing their responsiveness to pain and/or verbal stimulus. The AVPU scale should be used to assess the clients response of their eyes, voice, and motor skills.

• A: Alert
• V: Response to verbal stimuli
• P: Response to pain
• U: Unresponsive

Health History Assessment: SAMPLE

A health history is important to obtain after life-threatening injuries have been addressed and when the client has stabilized. SAMPLE can be used to obtain important parts of the client’s history.

• S: Symptoms
• A: Allergies
• M: Medications
• P: Past medical history
• L: Last oral intake
• E: Events leading up to the illness or injury

Rapid Trauma Assessment: DCAP-BTLS

This rapid trauma assessment is useful when assessing a client after a traumatic injury.

• D: Deformities
• C: Contusions
• A: Abrasions
• P: Punctures or penetrations
• B: Burns
• T: Tenderness
• L: Lacerations
• S: Swelling

Alcoholism Screening: CAGE

CAGE is a questionnaire to determine whether a client may suffer from alcoholism. A “yes” response to 2 or more questions indicate that alcoholism may be present and the client should be further treated.

• C: Have you ever felt that you should CUT down on your drinking?
• A: Have you ever become ANNOYED by criticisms of your drinking?
• G: Have you ever felt GUILTY about your drinking?
• E: Have you ever had a morning EYE OPENER to get rid of a hangover?

Emergency Trauma Assessment: ABCDEFGHI

Trauma clients can be complex and require haste when performing an accurate, in-depth health assessment. Each part of the emergency trauma assessment is intended to save the life of the client by taking action where it is appropriate.

• A: Airway
  • Make sure the airway is open and that the client is able to breathe. Tilt the head back and lift the chin to help open the airway and allow the client to breathe. Remove any obstructions to avoid respiratory or cardiac arrest.
• B: Breathing
  • Use look, listen, and feel techniques to ensure that the client is breathing. Be sure the chest is rising and falling in a normal respiration rhythm, you can hear air movement, and that you can feel air expelling from the mouth or nose. Initiate CPR if the client is not breathing.
• C: Circulation
  • If the client is breathing, check for the clients pulse. If the client is not breathing, initiate CPR immediately.
• D: Disability
  • Check that the client’s neurological status is intact and if there are obvious disabilities and/or deformities.
• E: Expose and examine
  • The client’s clothing should be removed to allow you to properly assess all parts of the client’s body for injury.
• F: Full set of vital signs
  • Note pulse (carotid, brachial, radial), pupils, breathing, level of consciousness, blood pressure, and skin color or temperature.
• G: Give comfort measures
  • Clients may be extremely anxious and/or in pain during a traumatic injury. Keep the client as comfortable as possible so they do not injure themselves further.
• H: History and head-to-toe assessment
  • SAMPLE is a good pneumonic to insert here in order to get a health history and a head-to-toe assessment.
• I: Inspect posterior surface
  • Examine the client for any obvious problems such as deformities, discolorations, wounds, or more.

Seven Warning Signs of Cancer: CAUTION

The seven warning signs of cancer help identify certain problems in order to detect cancer as early as possible. The American Cancer society uses “CAUTION” to identify the warning signs of cancer. These signs should not be used to definitively diagnose cancer, but may impose more testing and investigation.

• C: Changes in bowel or bladder habits
• A: A sore throat that does not heal
• U: Unusual bleeding or discharge
• T: Thickening or lump in the breast or other parts of the body
• I: Indigestion or dysphagia
• O: Obvious changes in a wart or mole
• N: Nagging cough or hoarseness

Breast Assessment: LMNOP

In addition to the CAUTION warning signs, LMNOP is used to screen for and identify breast cancer, cysts, abscesses, and mastitis. Any changes in breasts or masses warrant a further evaluation.

• L: Lump
  • Palpate the breast for any signs of lumps.
• M: Mammary changes
  • Palpate for any dimpling, tenderness, and abnormalities.
• N: Nipple changes
  • Observe nipple discharge, lesions, or discharges.
• O: Other symptoms
  • Symmetry, skin appearance, point direction, rashes, ulceration etc.
• P: Client risk factors
  • Ask client about any predisposing factors, family history.

Family History Assessment: BALD CHASM

Family history plays a large role in a client’s health. Family history can identify diseases the client is at risk for, chronic illnesses, and diseases that may have been genetically inherited. The following disorders have found to be strongly correlated with a family history of the diseases and should be screened for regularly if a family history is present.

• B: Blood pressure
• A: Arthritis
• L: Lung diseases
• D: Diabetes
• C: Cancers
• H: Heart disease
• A: Alcoholism
• S: Stroke
• M: Mental health disorders

Eye Abbreviations3

Short abbreviations for the eyes can be hard to keep straight. OU stands for both eyes, OD stands for right eye, and OS stands for left eye. The following pneumonic can help you remember which abbreviation stands for which term.

• YOU look with BOTH EYES
• The RIGHT dose won’t OD (overdose).
• The only one LEFT is OS.

Signs vs. Symptoms

Signs and symptoms are both important to identify a client’s problems and the correct treatment path. Distinguishing between signs and symptoms is important.

• sIgn: something I can detect even if my client is unconscious
• Symptom: something only the client knows about. Cannot be measured directly.

Pain Assessment: OPQRSTU

Assessing pain is very important to ensure that the client is comfortable. Pain can be a traumatic feeling for a client and can lead to further injury, anxiety, and can lengthen the time a client takes to recover. Pain is subjective to each client and a thorough assessment must be done.

• O: Onset
  • When did the pain start? How long does the pain last? How often does the pain occur? What started the pain?
• P: Provoking or palliating factors
  • What brings it on? What makes it better or worse?
• Q: Quality
  • What does the pain feel like? (Throb, stab, dull pain)
• R: Region and Radiation
  • Does the pain radiate? Where does it spread to?
• S: Severity
  • What is the intensity on a pain scale of 1-10? (or visual scale).
• T: Time and treatment
  • When did the pain begin? Do you take any medications for the pain?
• U: Understanding and Impact
  • What do you think is causing the pain? How is this affecting you?

Conclusion:

Health assessments are critical to providing comprehensive care to clients. Performing a head-to-toe assessment, as well as disease-specific assessments, is a crucial responsibility of a nurse and has a large impact on client care. Health assessments identify injury and disease, prevent disease progression, help curate treatment and therapy plans, and help identify diseases the client may be at risk for. Health assessments can be overwhelming due to the sheer amount of data that should be recorded with each assessment. This health assessment NCLEX^® review serves as an overview of the importance and how to perform health assessments to aid your understanding and help your future practice as a nurse.

References

1. Lee N. “How to Conduct a Head-to-Toe Assessment”. Nurse.Org. Accessed: May 12, 2020. https://nurse.org/articles/how-to-conduct-head-to-toe-assessment/
2. Haugh KH. Head-to-toe: Organizing your baseline client physical assessment. Nursing. 2015;45(12):58‐61.
3. Vera M. Nursing Health Assessment Pneumonics & Tips. Accessed: May 12, 2020. https://nurseslabs.com/nursing-health-assessment-mnemonics-tips/
4. Romanelli D, Farrell MW. AVPU (Alert, Voice, Pain, Unresponsive). In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2020.
5. Ewing JA. Detecting alcoholism. The CAGE questionnaire. JAMA. 1984;252(14):1905‐1907. doi:10.1001/jama.252.14.1905
6. Thim T, Krarup NH, Grove EL, Rohde CV, Løfgren B. Initial assessment and treatment with the Airway, Breathing, Circulation, Disability, Exposure (ABCDE) approach. Int J Gen Med. 2012;5:117‐121. doi:10.2147/IJGM.S28478
7. Bleyer A. CAUTION! Consider cancer: common symptoms and signs for early detection of cancer in young adults. Semin Oncol. 2009;36(3):207‐212. doi:10.1053/j.seminoncol.2009.03.004

Introduction: What are EKGs?

Electrocardiograms (abbreviated as EKG or ECG interchangeably) are key diagnostic tools when attempting to analyze cardiac rhythm, conduction abnormalities, and for ischemia in the heart. They may also be used to evaluate the severity of certain cardiac abnormalities (E.g. heart disease, cardiomyopathy, pericarditis, and hypertension).

Before diving into EKGs, it is imperative to refresh on the basics of cardiac conduction as well as the anatomy of the heart. The heart is composed of four different chambers with two pairs of atria and ventricles. In between the chambers of the heart there are valves which open and close based on when the atrium and ventricles are contracting.

Clinicians may evaluate the sounds of the heart to detect a heart murmur utilizing a stethoscope. The normal heart will make an iconic “lub dub” sound as it beats. The “lub” sound corresponds with the closing of the mitral and tricuspid valves at the start of systole (ventricles contracting); where the “dub” sound corresponds with the closure of the aortic and pulmonic valves.

The contraction of the heart is due to the flow of electrical conduction from the sinoatrial node (SA node), commonly called the pacemaker. The SA node fires at about 60-100 bpm in the normal healthy adult, this is called normal sinus rhythm and corresponds with the client’s heart rate. From the SA node electricity flows into the atrioventricular node (AV node).

Occasionally the SA node may fail due to certain medical conditions – from this the AV node can become the new pacemaker which fires at 40-60 bpm. Therefore, the SA node is sometimes called the backup pacemaker. Electricity then flows into the bundle of His, then into the Purkinje fibers which is responsible for squeezing the ventricles. Purkinje fibers also contain pacemaker cells which may serve as the last backup for electrical conduction in the heart – firing at 40-60 bpm.

Reading EKGs can be challenging but proves to be an important part of daily medical practice. A firm understanding of EKGs can enable nurses and other practitioners to help detect and manage clients with cardiac abnormalities. Hopefully, reviewing this NCLEX^® Review of EKGs will aid in understanding this critical aspect of practice.

How are Nurses Supposed to Read EKGs?

Reading EKGs can be a challenging process – especially when attempting to do so without training. Nevertheless, reading EKGs becomes a common practice for nurses and other clinicians every day. Electrocardiograms portray several waves that corresponds with the depolarization and contraction of different parts of the heart. Overall, the EKG monitor will reveal several waves which can be read as PQRST. The P-wave corresponds with the depolarization and squeezing of the atrium, the QRS-wave signifies squeezing of the ventricles, and the T-wave demonstrates the relaxation and repolarization of the ventricles.

To read EKGs you can use a 5-step process to guide you in assessing a client’s cardiac condition.

Step 1: Calculate sinus rate 

To determine the sinus rate, count the R peaks then multiply by 10. This will represent the number of beats per minute as the monitor will only display a few seconds worth of electrical impulses. When interpreting this information, it is important to know that the normal sinus rhythm (NSR) usually leads to 60-100 pulses per minute. Normal sinus brady represents a slow rate when < 60 bpm. Normal sinus tachy is described as > 100.

Step 2: Assess the rhythm

The rhythm should be regular and evenly spaced out between peaks. When the pattern appears to reveal abnormally spaced out pulses this may indicate the client has an arrythmia. Here you should assess all of the waves including for the presence and regularity of the P and QRS waves.

Step 3: Assess the P-wave

Determine if the P-wave looks normal – this will get easier with practice. Abnormalities in the P-wave may suggest abnormalities with atrial depolarization. The duration that is usually observed should be <0.12 seconds.

Step 4: Assess the PR interval 

The PR interval includes the P-wave as well as the PR segment. Measured from the beginning of the P-wave to the first part of the QRS complex. A normal PR interval will be shown as < 5 mini boxes with a normal reading between 0.12-0.20 seconds. PR intervals are shorter with faster heart rates signifying a sympathetically mediated upregulation of AV nodal conduction. Short PR intervals may suggest Wolff-Parkinson-White syndrome, long PR intervals may represent AV node blockage.

Step 5: Asses the QRS complex 

This represents the time for the ventricles to depolarize and contract. The QRS duration normally takes 0.06-0.10 second which is not influence by heart rate. Increased voltage may indicate left or right ventricular hypertrophy.

Example Questions for NCLEX^® Review for EKGs:

Common Nursing Interventions for EKGs

There are several nursing interventions to keep in mind with respect to EKG analysis. The main goal is to restore the heart to normal rhythm. There are many potential causes of EKG abnormalities so treating the underlying issues should be the primary approach. Reporting abnormalities to clinicians is also an important intervention to aid in diagnosis of cardiac abnormalities.

When clients present with a normal sinus brady (< 60bpm) there are several interventions that may be made. After confirmation of normal sinus brady the client should be assessed for signs and symptoms of low perfusion (low oxygenation). Two key signs include pale dusty skin and cyanotic blue lips. This suggests evidence of hemodynamic instability. A key treatment for clients showing these signs is atropine. This should upregulate sympathetic tone and improve the normal sinus brady. Other potential options clients can take includes dopamine or epinephrine to improve blood flow and tissue perfusion.

It is also imperative to recognize that clients with normal sinus brady may be exhibiting these symptoms as a result of drug overdose. Certain drugs that can cause this complication are those that are negative chronotropic which decrease heart rate. Examples of medications that can achieve this effect include beta blockers, certain calcium channel blockers (e.g. verapamil, diltiazem), and digoxin. Therefore, withholding the medications that can contribute to this side effect or reducing the dose is the main intervention.

Clients that present with normal sinus tachy the main approach is to determine the underlying etiology. On rare occasions clients with sinus tachycardia may have hypotension or shock related to fluid depletion – these clients should be admitted and assessed for potential heart failure, hypoxia, or for other potential conditions. Sinus tachycardia may present in clients in clients with acute myocardial ischemia. Less severe causes of tachycardia can include fear, anxiety, or due to potential medications.

Treating clients with tachycardia often involves discontinuation or reduction in the dose of certain medications. For clients where their rhythm does not appear to be resolved through these measures – it is reasonable to initiate a trial of beta blockers. For clients with persistently symptomatic tachycardia may benefit from the addition of ivabradine which helps to further decrease heart rate. Another potential treatment includes catheter ablation where small scars are created on the heart tissue to slow the electrical signals.

Common Diseases that Impact EKGs

There are many potential diseases that can impact EKG readings. It is critical to review the types of disease states and situations that can contribute to these abnormalities.

Arrhythmia: 

Arrhythmias can be caused by a variety of conditions including medications, genetic abnormalities, or structural abnormalities of the heart. Certain medications may increase the odds of having an arrhythmia by prolonging the QT interval. Examples of drugs that can contribute to QT prolongation includes (antidepressants, fluoroquinolones, macrolides, antipsychotics, amiodarone, antihistamines, etc.)

Treating the arrhythmia can often be complex with multiple therapeutic considerations. Occasionally clients will not be eligible to have their arrhythmia cured so they may have their heart rate suppressed instead of rhythm correction. Rhythm correction can be achieved by either cardioversion via electrical shock or via certain medications (e.g. amiodarone).

Electrolyte imbalances:

Electrolyte imbalances can contribute to abnormalities on the EKG reading. Several electrolytes may potentially alter the conduction of the heart including potassium, sodium, calcium, and magnesium. Assessing the client’s electrolyte levels is an important intervention to consider prior to looking for other etiologies.

Myocardial infarction/ischemia: 

EKG abnormalities are likely in clients who are having a heart attack. In these clients you can observe acute ST-elevation myocardial infarction (STEMI). It is possible for clients to be having no ST-elevation despite showing signs of a heart attack as well. Myocardial ischemia and infarction can also lead to EKG changes such as T-wave inversion.

Conclusion: NCLEX^® Guide for EKGs

EKGs are a very important diagnostic tool to use when evaluating clients for many kinds of medical conditions. Reading EKGs can prove to be a complicated process that will often become easier with continued practice. This includes myocardial infarction, electrolyte imbalances, and arrhythmias. For this reason, it is imperative to refer to this NCLEX^® Review for EKGs to aid in studying for the NCLEX^® exam and for daily practice.

Example Questions for NCLEX^® Review for EKGs:

References:

1. Basic Heart Sounds. http://www.stethographics.com/main/physiology_hs_introduction.html. Accessed April 12, 2020.
2. UpToDate. https://www.uptodate.com/contents/ecg-tutorial-basic-principles-of-ecg-analysis Accessed April 12, 2020.
3. UpToDate. https://www.uptodate.com/contents/sinus-bradycardia April 12, 2020.
4. UpToDate. https://www.uptodate.com/contents/sinus-tachycardia-evaluation-and-management April 12, 2020.
5. Johnson J. Abnormal EKG: Results, causes, and treatment. Medical News Today. https://www.medicalnewstoday.com/articles/324922. Published April 9, 2019. Accessed April 12, 2020.
6. UpToDate. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician?search=arrhythmia-management-for-the-primary-care-&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1 Accessed April 12, 2020.

Introduction to ABG NCLEX^® Review

It is imperative to develop a firm understanding of arterial blood gases (ABG) as they play a key role in practice as a nurse. At first, it may often be difficult to read ABGs as the subject depends on understanding of complex physiological processes. The complexity of this topic may often steer nurses and other practitioners into believing that blood gas interpretation may be the job of respiratory therapists or reserved for physicians to understand. Instead, it is important for all healthcare workers to have a strong understanding of ABGs as this can dramatically impact the outcomes of clients hospitalized with respiratory or metabolic acidosis. This ABG NCLEX^® Review aims to provide readers with a thorough understanding of arterial blood gases in order to prepare for both daily practice as a nurse and for the NCLEX^® exam.

Key concepts for ABG NCLEX^® Review

When trying to interpret ABGs the first step will always be to determine whether the client has normal values, acidic, or basic (alkalotic) measurements. The first step will be to observe the pH of the blood via laboratory tests. The next step will be to evaluate the partial pressure of carbon dioxide (PaCO2) and the concentration of bicarbonate (HCO3) in the serum. Refer below for the normal values of these laboratory parameters to aid in your evaluation of blood gases.

• Normal pH: 7.35 – 7.45
• PaCO2: 35-45 mmHg
• Bicarbonate (HCO3): 21-27 mEq/L

When a client presents with a pH that is out of the normal range you can interpret the value as either acidic or basic. Acidosis is observed when the pH is below the normal range < 7.35 where alkalosis or (basic blood gas) is measured as > 7.45.

PaCO2 in general is referring to the concentration of carbon dioxide in the blood. Abnormalities in these readings will indicate that the client is having a respiratory issue as opposed to a metabolic issue. In short, it may suffice to know that higher concentrations of carbon dioxide will increase the acidity of the blood (therefore lowering the pH). Thus, values > 45 mmHg can be interpreted as respiratory acidosis where values < 35 mmHg are considered respiratory alkalosis. Notice that high values in this case suggest acidosis, in contrast to pH where high values suggest alkalosis.

You may recall from basic chemistry that bicarbonate (HCO3) is a basic chemical compound that serves the purpose of raising pH (decreasing acidity). Therefore, elevated bicarbonate readings (> 27 mEq/L) will result in an increase in pH causing alkalosis. In this case, you can interpret these values as metabolic alkalosis as it has nothing to do with the expiration or inhalation of CO2. Clients who have values < 22 mmHg may have metabolic acidosis as the concentration of bicarbonate in the blood is low, therefore lowering the blood pH and causing acidosis.

Unfortunately, when reading blood gases, it may be necessary for practitioners to take additional considerations with respect to the bodies tendency to compensate for pH abnormalities. This may complicate matters as it may appear that the pH of the blood is within normal limits (e.g. between 7.35-7.45) but still indicative of potential underlying issues.

Compensation mechanisms often make interpretation of ABGs very difficult, so it is important to keep some basic concepts in mind. First, clients that present with primary metabolic acidosis may have a disorder causing decreased bicarbonate. The body will compensate this by increasing the rate of expiration of carbon dioxide via the lungs to drive the pH of the blood up.

Clients that present with primary metabolic alkalosis may have increased levels of bicarbonate in the body. The body will compensate for this by reducing the ventilation of carbon dioxide, thus retaining more pCO2 in the blood causing compensation of the pH abnormality.

Compensation of primary respiratory alkalosis and acidosis generally involves the kidney’s ability to either retain bicarbonate or increase the excretion of it. Retention of bicarbonate of course will increase the pH of the blood where excretion of it will decrease it.

For example, a client may have respiratory acidosis as they were initially failing to expire the appropriate amount of carbon dioxide from the body. As a result, the kidneys will opt to retain more bicarbonate in order to increase the pH of the body and temporarily resolve the blood pH. Upon arriving to the hospital, it may appear that the client has a normal pH despite having high readings of both carbon dioxide and bicarbonate. This would be an example of fully compensated respiratory acidosis.

Causes of abnormalities for ABG NCLEX^® Review

There are many different underlying causes of blood gas abnormalities to consider when evaluating clients. It is imperative to know the various causes of these abnormalities as ultimately the goal will be to treat the cause rather than the symptoms.

Metabolic acidosis can be caused by several underlying conditions that can contribute to the increased acidity observed in the blood. Below are several examples of causes to keep in mind when evaluating clients with this condition.

• Salicylate poisoning (e.g. aspirin overdose)
• Lactic acidosis (caused by poor oxygen perfusion of tissue increase anerobic respiration)
• Uremia (caused by renal failure)
• Medications
  • Antidiabetic medications – metformin
  • Antibiotics – linezolid
  • Anti-seizure – topiramate
• Diabetic or alcoholic acidosis
• Gas or heavy metal poisoning

Respiratory acidosis involves the failure of the lungs to expire carbon dioxide from the body – therefore increasing the acidity of the blood (reducing the pH). This can be caused by varying types of respiratory failure. Respiratory failure occurs when the lungs fail to fully oxygenate the blood (leading to low pO2) causing hypoxia or failure of the lungs to properly ventilate causing hypoventilation. Below are several examples of causes of respiratory acidosis.

Poor oxygen diffusion (hypoxemic respiratory failure) 

• Alveolar hypoventilation (e.g. opiate overdose, benzodiazepine overdose)
• Ventilation-perfusion mismatch (e.g. COPD, cystic fibrosis)
• Impaired diffusion (e.g. diffuse parenchymal lung disease)
• Low partial pressure of inspired oxygen (e.g. high altitude)

Hypoventilation 

• Musculoskeletal problems (e.g. muscular dystrophy)
• Airway obstruction (e.g. epiglottitis)
• Neuropathy (e.g. motor neuron disease, Guillain-Barre syndrome)
• Neuromuscular junction problem (e.g. myasthenia gravis)
• Extrapulmonary issues (e.g. severe ascites)
• Respiratory center suppression (e.g. brainstem stroke, propofol overdose)
• Spinal cord tension

Example questions for ABG NCLEX^® Review:

Conclusion for ABG NCLEX^® Review

Blood gases often prove to be a difficult yet very important subject to understand when treating clients with abnormal blood gases. Blood gas abnormalities can often be caused by a variety of conditions that can often be life-threatening for the client. For this reason, it is imperative to not only know how to recognize clients with ABG values that are out of the ordinary – but to also screen for the cause in order to resolve the issue and improve your client’s outcomes. Hopefully this ABG NCLEX^® Review will serve as a good overview of the subject matter to aid in your understanding of the topic and to serve you in your future practice.

References:

1. Arterial Blood Gases. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed May 5th, 2020.
2. Yap CY, Aw TC. Arterial Blood Gases. Proceedings of Singapore Healthcare. 2011;20(3):227-235. doi:10.1177/201010581102000313.
3. ABA Keywords. OpenAnesthesia.https://www.openanesthesia.org/aspirin_toxicity_treatment/. Accessed May 10, 2020.

Introduction to Dosage Calculation NCLEX^® Review

Calculating the correct dose of medication to be delivered to clients is a large and essential part of a nurse’s job. Nurses are expected to be able to comfortably perform many types of dosage calculations quickly and accurately in order to care for their clients. While dosage calculations can seem intimidating at first, they are largely intuitive and quickly become easier with a little practice. This Dosage Calculation NCLEX^® Review aims to provide readers with an understanding of this topic in order to prepare nurses for the NCLEX^® exam, as well as their daily responsibilities.  While not conclusive, this review provides directions for how to perform some of the most common types of dosage calculations.

Key Concepts for Calculation NCLEX^® Review

The following concepts will be discussed in this article.

• Units of Measurement and Abbreviations for Dosage Calculation NCLEX^® Review
• Flow Rate Dosage Calculations NCLEX^® Review
• Weight Based Dosage Calculation NCLEX^® Review
• Renal Impairment Dosage Calculation NCLEX^® Review
• Body Surface Area Dosage Calculation NCLEX^® Review
• Conclusion to Dosage Calculation NCLEX^® Review
• Practice Questions

Units of Measurement and Abbreviations for Dosage Calculation NCLEX^® Review

Understanding the units of measurement and knowing how to convert between them is the foundation to being able to perform dosage calculations. The following are ways to measure three different units used in calculations; volume, weight, and height.

Volume

1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces
1 L = 1000 mL
1 mL = 20 gtts
1 tsp = 5 mL
1 tbsp = 15 mL
1 fl oz = 30 mL
1 cup = 250 mL
1 pt = 500 mL
1 qt = 950 mL
1 gallon = 3.8 L = 3800 mL

Mass

1 lb = 16 oz
1 g = 1000 mg
1 kg = 1000 g
1 kg = 2.2 lb

Length

1 ft = 12 in
1 yd = 3 ft
1 mi = 1760 yd = 5280 ft
1 cm = 10 mm
1 m = 100 cm
1 km = 1000 m

1 in = 2.54 cm

Flow Rate Dosage Calculations NCLEX^® Review

IV infusions are a mainstay in the nursing world, and so understanding how to use them to deliver an appropriate dose is essential. Because IV’s deliver a certain dose (mg) of liquid (ml) over time (t), we must take these three factors into consideration for this type of calculation.

Consider this scenario; a client requires a 500mg dose of a medication given over a 1 hour infusion. The medication on hand is available in a 1000mg/1L solution. What would the appropriate flow rate be to deliver the correct amount of medication to the client?

First, let’s review what we already know. We know that the infusion must last 1 hour, which equals 60 minutes. We also know that the client requires a 500mg dose, and that the drug on have comes is a 1000mg/1L formulation.

Let’s figure out the volume of solution the client would need in order to get the correct dose by setting up a ratio:

(dose available) / (volume available) = (dose desired) / volume desired)

(1000mg) / (1 L) = (500mg) / (? L)

First we cross multiply the numerator and the denominator (500 x 1 = 500). Next, we divide by the remaining numerator (500 / 1000 = 0.5).

We now know that the client requires 0.5 L to receive the correct dose, but let’s take this a step further and convert this answer to mL.

1 L = 1000 mL…. so that means 0.5 L = 500 mL

Lastly, we need to figure out the amount of volume that needs to be delivered per minute in order for the full dose to be delivered in 1 hour. We do this by simply dividing the volume by the number of minutes in an hour (60).

500 mL / 60 min = 8.33 mL per minute. For simplicity, let’s round this to 8 mL per minute.

And there’s our answer! In order for the client to receive 500mg of an IV solution over 1 hour using a formulation of 1000mg / 1L, we need to deliver approximately 8 mL per minute.

Weight Based Dosage Calculation NCLEX^® Review

Because people come in all shapes and sizes, not everyone requires the same dose of medication. To account for this, many medications are dosed using the client’s weight. (usually in kg).

Consider this scenario: The recommended dosage of a drug is 2mg/kg. What does should a client weighing 195lbs receive is the medication only comes in 25mg tablets?

To answer this question, we must first convert pounds to kilograms. To do this, we simply divide by the conversion factor 2.2

195 / 2.2 = 88.6kg

Since we know the recommended dose is 2 mg for every 1 kg, all that’s left to do it multiply our two numbers.

2 x 88.6 = 177.2 mg

Because the medication only comes in 25mg tablets, we can round this answer down to 175mg, which is 7 tablets.

Body Surface Area Dosage Calculation NCLEX^® Review

Another way to account to different body types is to calculate dosing using body surface area (BSA). To do this, we must become familiar with the BSA formula.

BSA (m2) = √(height (cm) x weight (kg)) / 3600)

Consider this scenario: A client weighing 150lbs who is 5’8” tall requires treatment with a certain medication whose recommended dosing is 2mg / m2. What is the correct dose for this client?

Once again, we start by laying out what we know and converting to the appropriate units for the formula.

150 lbs / 2.2 kg = 68.2kg

5’8” =  68 in

68 in x 2.54 cm = 172.7cm

Now let’s plug these numbers into the formula

√((172.7 x 68.3) / 3600)         =     √(3.28)       =    1.8 m2

Now that we have calculated the client’s BSA, we only have to multiply it by the dose per BSA provided.

2mg / m2   = 2mg / 1.8m2   =   3.6mg

Renal Impairment Dosage Calculation NCLEX^® Review

Many medications are eliminated out of the body through the kidneys, meaning clients with impaired kidney function may require a dose adjustment to account for this. A popular way to calculate kidney function is by using the Cockroft-Gualt equasion, which provides us with an estimation of kidney function known as creatinine clearance (CrCl).

CrCl(mL/min)  = ((140 – age) x IBW) / (72 x Scr)   🡨 (multiplied by 0.85 for females)

You’ll notice that in order to use this equasion, we need a measurement of serum creatinine (Scr), as well as the client’s Ideal Body Weight (IBW) which must be calculated separately using the following formulas.

Males: IBW(kg) = 50 + (2.3 x inches over 60”)

Females: IBW(kg) = 45.5 + (2.3 x inches over 60”)

Consider this scenario: A 51 year old female has a Scr of 1.4, is 63in tall, and weighs 55kg. What is her CrCl?

First we must calculate the client’s IBW using the formula for females.

IBW = 45.5 + (2.3 x 3) = 54.2kg

Since we already have the other required info, we can simply plug these numbers into the formula.

CrCl = (((140 – 51) x 54.2) / (72 x 1.4)) x 0.85

CrCl = ((4823.8) / (100.8)) x 0.85

CrCl = 40.68 mL/min

If a medication had the following recommended dosages, which dose would be appropriate for this client?

CrCl:    ≥ 60mL/min, no dose adjustment necessary

CrCl:    30mL/min – 59mL/min, reduce dose by half

CrCl:    ≤ 29mL/min, do not use

Because the client’s calculated CrCl falls between 30 and 59, we would need to reduce the client’s dose by half.

Conclusion to Dosage Calculation NCLEX^® Review

Calculating correct dosages using a variety of methods is a skill that nurses will use every day. It is therefore extremely important for nurses to possess a solid understanding of this topic. Fortunately, this skill can be mastered with a little time, clients, and most of all, practice!

Practice Questions

References

Med Math for Nurses Master Post (everything about dosage calculations and dimensional analysis . . . with practice). Nursing.com. https://nursing.com/blog/med-math-dosage-calculations/. Accessed May 24, 2020.

Dosage calculations the easy way. Straight A Nursing. https://www.straightanursingstudent.com/dosage-calculations-the-easy-way/. Accessed May 24, 2020.

Metric conversion charts and calculators for metric conversions. Metric Conversions.  https://www.metric-conversions.org/. Accessed May 24, 2020.

Pediatric dosage calculations. Nursing Central. https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Drug-Guide/109514/all/Pediatric_Dosage_Calculations. Accessed May 24, 2020.

Introduction to Acute Coronary Syndrome

Acute Coronary Syndrome, or ACS, is an umbrella term used to describe a set of similar conditions that result in the death of cells within the heart due to blocked blood flow to this organ. These conditions are ST-Elevated Myocardial Infarction (STEMI), Non ST-Elevated Myocardial Infarction (NSTEMI), and unstable angina.

Acute Coronary Syndrome is a very serious condition that can be life threatening and require immediate treatment in order to save as much heart tissue as possible. ACS is a type of Coronary Heart Disease (CHD) which affects over 15 million Americans and is responsible for 1/3 of total deaths in individuals over 35 years of age.

Causes of Acute Coronary Syndrome

Unhealthy lifestyle or a variety of other factors can result in high levels of cholesterol in the body. This cholesterol can build up in blood vessels over time to form plaques. When one of these plaques eventually ruptures, a thrombus (or blood clot) can form which becomes lodged in the vessel and blocks sufficient blood flow through the area, starving the heart of oxygen. If severe enough, this lack of oxygen can result in cell death in the heart tissue which is known as a myocardial infarction, also called a heart attack. When this blockage does not result in cell death, it is referred to as unstable angina. Even without cell death, heart cells may still become damaged and their function may become temporarily or permanently impaired.

Though not directly caused of ACS, there are many factors that can drastically increase the risk of heart events such as Acute Coronary Syndrome. Here are a few examples.

Age

As a person ages their blood vessels naturally become harder and less flexible, increasing their risk for heart disease.

Hypertension

Chronic high blood pressure puts constant strain on blood vessels and certain organs, including the heart. Over time this stress can weaken the heart and place it at higher risk for disease.

Hypercholesterolemia

A high level of cholesterol is a direct risk factor for heart disease. If untreated, this cholesterol can form dangerous plaques in blood vessels.

Smoking

Smoking, particularly cigarette smoking, drastically increases the risk for cardiac events through a number of ways. When done on a regular basis, smoking reduces oxygen levels in the blood, promotes blood clot formation, reduces levels of HDL “good cholesterol” in the blood, and can even trigger spasms and irregular heartbeats.

Sedentary Lifestyle

Participating in a sedentary lifestyle makes necessary blood circulation more difficult and denies the heart of the exercise it needs to remain strong and healthy.

Diabetes

Similar to hypertension, diabetes places a large amount of stress on the heart which may cause it to become more susceptible to disease.

Diet

An unhealthy diet can lead to a range of factors that greatly increase the risk of heart disease. Fat stores will increase in the body over time and cholesterol levels will rise as a result of a consistently unhealthy diet.

Obesity

Often a result of lack of exercise and/or an unhealthy diet, obese individuals tend to have much higher levels of cholesterol, higher blood pressure, increased risk for diabetes, and so on.

Family History

Unfortunately, genetics can also play a role in the likelihood of developing heart disease. Those with a strong family history of ACS are more likely to develop this condition.

Signs and Symptoms of Acute Coronary Syndrome

The symptoms of Acute Coronary Syndrome typically begin quite rapidly, and since this condition can be so dangerous it is essential to be able to recognize the early signs and symptoms of a heart event. The most common signs and symptoms of ACS are as follows.

• Chest pain typically described as throbbing, tightness or burning
• Pain spreading from the chest up to the upper torso including the shoulders, arms, back, neck, and/or jaw
• Nausea
• Indigestion
• Difficulty breathing
• Sweating
• Dizziness
• Fatigue
• Restlessness

If any of these symptoms are experienced or you have any other reason to believe you may be experiencing a coronary event, call 911 immediately.

Clinical Manifestations

In addition to the above mentioned signs and symptoms, Acute Coronary Syndrome can also result in a number of other clinical manifestations which can be useful for the conformation and diagnosis of this condition.

Creatine Kinase (CK)

Creatine Kinase is an enzyme commonly found within the cells of muscle tissue and is released into the bloodstream when cell damage occurs. Because CK levels can rise for several reasons other than cardiac injury, this test is not conclusive, though it can be useful to provide diagnostic hints and determine if additional testing is necessary.

Creatine Kinase-MB Isoenzyme

The MB isoenzyme of creatine is significantly more cardio specific than CK, and is often measured quickly upon admission. While this test can help determine if a cardiac event occurs, it does not provide evidence for how large of an event occurred.

Cardiac Troponins

Troponins are another substance found within muscle cells with some forms being specific to cardiac muscle. Similar to creatine kinase, troponins are released into the bloodstream when muscle damage occurs, though these markers are more cardiac-specific than CK making them the preferred cardiac serum markers to test for heart damage.

Myoglobin

Another serum biomarker, myoglobin has low cardiac specificity but very high sensitivity. This means that if myoglobin levels are normal, no cardiac damage is likely to have occurred. This marker is used in conjunction with the others for diagnostic purposes.

Electrocardiogram (ECG)

Perhaps the most definitive diagnostic test, an ECG is a test where electrodes are attached to the skin to measure the activity of the heart to determine if it is operating correctly.

Test your knowledge with these examples of NCLEX^® questions:

Treatment

Pharmacology of Acute Coronary Syndrome

Initially, treatment of ACS should be focused on restoring blood flow to the heart as quickly and effectively as possible to minimize damage. Additionally, symptoms such as chest pain should also be addressed. Long term treatment goals should be targeted towards maintaining proper heart function and lowering the risk of a similar occurrence happening again.  The following are types of medications that may be used for ACS.

Thrombolytic Drugs

This type of medications may be useful in the early stages of ACS treatment as they are used to help breakup blood clots that may be the cause of the event. Examples of thrombolytic drugs are reteplase, anistreplase, tenecteplase, and streptokinase.

Antiplatelet Drugs

Antiplatelet drugs are commonly used to reduce the risk of blood clot formation, often for a predetermined amount of time after a cardiac event. Examples of antiplatelet drugs include aspirin, clopidogrel, and prasugrel.

Nitroglycerin

Nitroglycerin is commonly prescribed to clients with a history or high risk of heart events. It is intended to be used in emergency situations to help maintain blood flow to the heart until further treatment can be received. Nitroglycerin is typically dissolved under the tongue and works by rapidly dilating blood vessels, allowing blood the room to flow past a blockage.

Beta Blockers

This class of medication provides several benefits by reducing blood pressure and slowing the heart. Both of these actions are useful for reducing strain on the heart and some beta blockers have been shown to improve the mortality rate of heart disease clients. Examples include carvedilol, metoprolol succinate, and bisoprolol.

Angiotensin Converting Enzyme Inhibitors (ACE-Inhibitors)

A mainstay for the treatment of hypertension, ACE Inhibitors can also provide significant benefit to clients with ACS. ACE Inhibitors help to protect the heart by reducing blood pressure, and also provide protective benefits to the kidneys as well. Examples include lisinopril and enalapril.

Angiotensin Receptor Blockers (ARBs)

Similar to ACE-Inhibitors, ARBs are typically used to lower blood pressure and provide some mortality benefit. ARBs are never used in conjunction with ACE-Inhibitors, a client is placed on either one or the other at any given time. Examples include losartan, candesartasn, and valsartan.

Statins

When it comes to providing mortality benefits, statins are difficult to top. These medications have been shown to greatly reduce levels of harmful LDL cholesterol, drastically lowering the change of further plaque formation. Examples of statins include atorvastatin, simvastatin, and rosuvastatin.

Stents

One non-drug treatment for ACS is the placement of a stent. Stents can be carefully inserted into the blocked artery and are used to compress the plaque buildup against the vessel wall to restore blood flow. Many stents are left within the artery to hold the passageway open.

Coronary Bypass Surgery

In some instances, the blockage may not be able to be removed. Coronary Bypass Surgery offers an alternative solution. In this surgical procedure an artery (usually harvested from the leg) if grafted around the heart to circumvent the blockage.

Test your knowledge with these examples of NCLEX^® questions:

Nursing Interventions

As with most critical conditions, nurses play a large part in the treatment of Acute Coronary Syndrome. In addition to the initial treatment and administration of medications, the role nurses play in the lifestyle recommendations of their clients should not be overlooked. Here are a few examples that nursing staff may provide education on to reduce the risk of future cardiac events.

Medication Adherence

While traditionally the job of a pharmacist or physician, clients can never be reminded too much of the importance to remain adherent to their medications. After a coronary event, many of the newly prescribed medications are intended to be taken or a significant amount of time, and possibly even for the rest of the client’s life.

DASH Diet

Making positive changes to diet is one of the best ways to lower the risk of heart disease. The DASH diet, which stands for Dietary Approaches to Stop Hypertension, provides a helpful framework for these changes. In addition to practicing healthy portion control, the DASH diet also recommends lowered sodium intake, more consumption of vegetable and lean meat, higher fiber intake, and consumption of whole grains. When practiced consistently, these dietary changes will help individuals to lose weight, lower cholesterol, and reduce blood pressure.

Regular Physical Exercise

Another counseling point that nurses should stress is the importance of participating in regular physical exercise. Not only does exercise help to lower blood pressure and cholesterol levels, but it also strengthens the heart and lowers fat reserves.

Smoking Cessation

Last but certainly not least, any client who has a history of smoking should be greatly encouraged to stop this harmful habit. Clients should be educated on the harms of smoking, as well as the slew of benefits that come from quitting. It should be reinforced that there are a variety of strategies, counseling types, and medications to help with smoking cessation.

Conclusion

Acute Coronary Syndrome is a type of heart disease that encompasses three main types of similar conditions; ST-Elevated Myocardial Infarction (STEMI), Non ST-Elevated Myocardial Infarction (NSTEMI), and unstable angina. Because heart disease affects millions of people within the US and accounts for such a staggering number of deaths, this topic is especially important for nursing staff to become familiar with in order to provide the best care possible to their clients.

References

Acute coronary syndrome. American Heart Association. https://www.heart.org/en/health-topics/heart-attack/about-heart-attacks/acute-coronary-syndrome. Accessed May 26, 2020.

Acute coronary syndrome. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/acute-coronary-syndrome/symptoms-causes/syc-20352136. Accessed May 26, 2020.

Diagnosis of acute coronary syndrome. American Family Physician. https://www.aafp.org/afp/2005/0701/p119.html. Accessed May 26, 2020.

Acute coronary syndrome. NCBI. https://www.ncbi.nlm.nih.gov/books/NBK459157/. Accessed May 26, 2020.

Smoking and coronary artery disease. American College of Cardiology. https://www.cardiosmart.org/Healthwise/hw79/682/hw79682. Accessed May 26, 2020.

Nutrition and healthy eating. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/dash-diet/art-20048456. Accessed May 26, 2020.

Introduction to NCLEX^® Review of Antihypertensives

Uncontrolled hypertension puts clients at an increased risk of having a serious cardiovascular disease including strokes, heart attacks, and even kidney failure. Today it is estimated that around 30% of Americans suffer from high blood pressure (HBP) contributing to a rising prevalence of several atherosclerotic disease (ASCVD) contributing to significant morbidity and mortality rates. It is crucial to understand the various types of antihypertensive treatments as they play a substantial role in practice today. This NCLEX^® Review of Antihypertensives is designed to provide a practical overview of the different antihypertensive classes, adverse effects, and nursing considerations.

Indications for NCLEX^® Review of Antihypertensives

• Hypertension
  • Confirmed: Systolic blood pressure (SBP) > 130 mmHg or Diastolic blood pressure (DBP) > 80 mmHg
• Chronic kidney disease
• Heart failure
• Post myocardial infarction (MI)
• Post transient ischemic attack (TIA)
• Post hemorrhagic stroke
• Diabetes w/ hypertension

Types of Drugs for Class of NCLEX^® Review of Antihypertensives

ACE inhibitors (ACEi) / Angiotensin receptor blockers (ARBs)

• MOA:
  • ACEi: Competitive inhibitor of angiotensin -converting enzyme preventing the conversion of angiotensin I to angiotensin II → vasodilation → reduced blood pressure
  • ARB: Angiotensin II receptor antagonist blocks the vasoconstrictor effects of angiotensin and aldosterone → vasodilation → reduced blood pressure
• Side Effects:
  • Hypotension
  • Reduction in GFR
  • Hyperkalemia
  • Cough – ACEi > ARB
  • Angioedema – ACEi > ARB
  • Anaphylaxis – ACEi > ARB
• Contraindications:
  • ACEi and ARBs are contraindicated in pregnancy
• Nursing Considerations:
  • Key counseling point:
    • It is important to take these medications every day as they will keep your blood pressure under control.
    • If you are pregnant or plan on getting pregnant contact your primary care provider (PCP)
    • There is a chance these medications can cause swelling of the tongue and throat – if you have trouble breathing on this medication contact your PCP immediately.
  • ACE inhibitors are more associated with the “dry cough” side effect and corresponding risk of angioedema and anaphylactoid reactions. In clients who experience these side effects, it is reasonable to try ARBs as an alternative which is less associated with these adverse effects.
  • These are generally first line treatments for primary and secondary hypertension – additional blood pressure reducing agents may be used in stage 2 hypertension (BP > 140/90)
  • Monitor potassium as these medications can cause hyperkalemia which can lead to arrythmias and cardiac events.
• Common Key Generics (Brands)
  • ACEi:
    • Lisinopril (Zestril, Prinivil)
    • Enalapril (Vasotec)
    • Ramipril (Altace)
    • Captopril (Capoten)
  • ARB:
    • Losartan (Cozaar)
    • Olmesartan (Benicar)
    • Valsartan (Diovan)
    • Candesartan (Atacand)
    • Telmisartan (Micardis)

Diuretics

• MOA:
  • Loop Diuretics: Increases the excretion of sodium (inhibits sodium reabsorption) and other ions (electrolytes) into the urine → pulls water out of the blood into the urine to be excreted → reduced blood pressure
  • Thiazides:  Increases the excretion of sodium (inhibits sodium reabsorption) and other ions in the distal convoluted tubule → increased excretion of water → reduced blood pressure
  • Potassium sparring: Increases sodium excretion through the collecting duct without reducing potassium levels → fluid loss → reduced blood pressure
  • Aldosterone antagonists: Increases sodium excretion through the collecting duct without reducing potassium levels + activity against mineralocorticoid receptor → fluid loss → reduced blood pressure
• Side Effects:
  • Electrolyte imbalances:
    • Loop diuretics, thiazide diuretics: Potassium loss, sodium loss, calcium loss
    • Potassium sparing: Sodium loss, potassium retention
    • Aldosterone antagonists: Sodium loss, potassium retention
  • Fluid management:
    • Many of these medications can cause significant loss of water.
    • Clients with edema or at risk of edema (e.g. heart failure) should monitor weight daily to assess for fluid retention.
  • Dehydration
  • Increased urination
• Precaution:
  • Potassium sparring diuretics and aldosterone antagonists may increase the risk of hyperkalemia – this can lead to arrhythmia which can cause serious cardiac complications. Hyperkalemia is defined as serum potassium > 5.5 mmol/L.
• Nursing Considerations:
  • Key counseling point:
    • You may have to monitor your weight daily to assess for fluid loss.
    • Take these medications as prescribed.
    • These medications can increase the risk of dehydration – monitor for signs and symptoms of dehydration (e.g. dry cracked skin) and hydrate as needed.
    • These medications will make you have to urinate more frequently – take these in the morning to avoid unwanted waking during sleep.
  • Potassium monitoring
• Common Key Generics (Brands)
  • Loop Diuretics:
    • Furosemide
    • Bumetanide
    • Torsemide
    • Ethacrynic acid
  • Thiazide Diuretics:
    • Hydrochlorothiazide (Microzide)
    • Chlorthalidone (Thalitone)
    • Indapamide
    • Metolazone
  • Potassium Sparring:
    • Triamterene
    • Amiloride
  • Aldosterone Antagonists:
    • Spironolactone (Aldactone)
    • Eplerenone

Beta blockers

• MOA:
  • Selective and/or nonselective blockade of beta-adrenergic receptors on the heart → decreased heart rate and force of contraction → reduced blood pressure
• Side Effects:
  • Increased risk of falling
  • Decreased energy
    • Fatigue
    • Depression
    • Sexual dysfunction
  • Risk of asthmatic exacerbation in nonselective beta-blockers (e.g. propranolol)
  • Hypoglycemia masking
• Warnings:
  • Risk of asthmatic exacerbation in clients with reactive airway disease – consider cardio-selective betablockers in clients with this comorbidity (e.g. metoprolol, bisoprolol, atenolol, nebivolol)
  • These medications can mask the effect of hypoglycemia – clients with diabetes should be made aware of this potential adverse effect. In clients with uncontrolled diabetes or in those who have frequent hypoglycemic events – increased blood sugar testing is advised.
• Nursing Considerations:
  • Key counseling point:
    • These medications will decrease your energy at first but generally this gets better within a few weeks.
    • This medication increases your risk of serious hypotension – especially when changing positions from sitting to standing too quickly causing orthostatic hypotension. It is important to take it easy when first starting on this medication.
    • If you have diabetes, consider increasing how often you check your blood sugars at first as these medications can mask the effects of hypoglycemia.
  • Clients with reactive airway disease should avoid non-selective beta blockers (e.g. labetalol, propranolol, carvedilol)
  • Carvedilol, nebivolol, and metoprolol succinate (ER) are preferred in clients for the treatment of heart failure.
  • Metoprolol tartrate is the instant release formulation of metoprolol, metoprolol succinate is the extended release (ER) formulation
• Common Key Generics (Brands)
  • Atenolol (Tenormin)
  • Carvedilol (Coreg)
  • Labetalol
  • Metoprolol (Lopressor, Toprol XL)
  • Nebivolol (Bystolic)
  • Propranolol (Inderal LA)

Calcium channel blockers (CCBs)

• MOA:
  • Dihydropyridines: Blocks the influx of calcium into the vascular smooth muscle tissue → vasodilation → reduced blood pressure
  • Non-dihydropyridines: Blocks calcium influx into vascular smooth tissue and myocardial tissue → vasodilation and reduced heart rate + force of contraction → reduced blood pressure
• Side Effects:
  • Edema (swelling in periphery)
  • Headache
  • Reduced heart rate (verapamil, diltiazem)
  • Increased risk of falling (verapamil, diltiazem)
  • Risk of heart block in HFrEF (verapamil, diltiazem)
• Warning:
  • Non-dihydropyridines should be avoided in clients with heart failure with reduced ejection fractions (HFrEF) as this can lead to heart bloack which can be fatal.
• Nursing Considerations:
  • Key counseling point:
    • These medications can cause swelling on your hands and feet – monitor your weight daily to assess for fluid retention.
    • These medications increase the blood flow in your brain which can cause headache.
    • If on verapamil or diltiazem these medications can slow your heart rate and increase your risk of falling – avoid sudden positional changes (e.g. sitting to standing)
  • Non-dihydropyridines (e.g. verapamil and diltazem) are generally used for clients who have tachycardia (HR > 100 bpm) and/or arrythmia
• Common Key Generics (Brands)
  • Dihydropyridines
  • Non-dihydropyridines

Key Nursing Tips for NCLEX^® Review of Antihypertensives

• Lifestyle interventions are often first line for clients who have stage 1 hypertension without serious risks of having an ASCVD event.
• Encourage lifestyle interventions as they can lead to significant blood pressure reduction
  • Exercise: 150 minutes of moderate-intensity workouts of 75 minutes of vigorous-intensity aerobic activity
  • Weight loss
  • Dietary sodium restriction (< 2 grams/day)
  • Alcohol < 2 drinks/day for men; < 1 drink per day for women
• Tobacco does not chronically elevate blood pressure – it does not cause hypertension but does increase the risk of major cardiovascular events.
• It is not uncommon for clients with hypertension to be on multiple classes of these medications (e.g. ACEi, beta-blocker, diuretics) to adequately control their blood pressure.
• Pregnancy: Many medications are either unsafe or unproven in clients who are pregnant. Below are some potential antihypertensive medications that are proven to be safe and effective in pregnancy.
  • Labetalol
  • Nifedipine
  • Hydralazine
• Many of these drugs can cause serious hypotension which can increase the risk of falling. Use with caution in elderly or in clients with renal failure.

Example NCLEX^® questions for NCLEX^® Review of Antihypertensives:

Conclusion for NCLEX^® Review of Antihypertensives

Hypertension is a highly prevalent disease that millions of Americans suffer from every year. It can increase the risk of having serious cardiovascular events (e.g. strokes, heart attacks). It is imperative to control your client’s hypertension as best as possible to reduce the risk of them suffering from serious ASCVD events – thereby reducing their risk of morbidity and mortality. For many clients, the first line therapy for hypertension is simply lifestyle interventions (e.g. weight loss, sodium restriction, exercise) but some clients may require medications to adequately control their blood pressure. For this reason, it is crucial to utilize this NCLEX^® Review of Antihypertensives to further develop your understanding of hypertension and how to treat it.

References

1. Arnett DK, Arnett DK, Blumenthal RS, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000678. Published March 17, 2019. Accessed April 23, 2020.
2. Townsend R. Major side effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
3. Lisinopril: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
4. Losartan: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
5. Brater CD, Ellison D. Mechanism of action of diuretics. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
6. Podrid P. Major side effects of beta blockers. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
7. Bloch M, Basile J. Major side effects and safety of calcium channel blockers. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
8. August P. Management of hypertension in pregnant postpartum women. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
9. Amlodpine: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
10. Verapamil: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.

Introduction to Antibiotics

In the year 1928 a researcher named Sir Alexander Fleming was studying petri dishes inoculated with colonies of Staphylococcus. He discovered that one of his dishes featured a blob of mold that appeared to resist the growth of the microbes. This mold was identified as Penicillium notatum – an organism secreting a substance that inhibited the growth of bacteria. From this point forward, the world would never be the same as Fleming had came across a lab accident that would soon lead to the creation of penicillin.

Infectious disease proves to be among the more challenging fields of medical practice based largely off the abundance of pathogens and antibiotics used to treat them. There are multiple classes of antibiotics that are used commonly in practice today – contributing to a vast spectrum of potency and adverse effect profiles. This NCLEX^® Pharmacology Review of Antibiotics will help to develop a firm grasp of the drug classes as well as commonly used medications as they play a key role in daily practice.

Indications for Antibiotics

Since the inception of penicillin researchers have developed many different drugs of various mechanisms. Penicillin and like antibiotics feature a beta-lactam structure disrupts the stability of bacterial cell walls leading to its antibacterial properties. Various penicillins like amoxicillin, nafcillin, and oxacillin were created which closely relate to penicillin specifically. From there cephalosporins were derived which exhibit broader antibacterial properties.

It is imperative to understand that certain antibiotics are more effective against specific microbes than others. Bacteria are classified based on gram stains which determines properties like gram-positive and gram-negative bacteria. Vancomycin for example is an antibiotic that exhibits strong antibacterial properties against gram positive organisms – where penicillins and cephalosporins often have more mixed gram negative and gram-positive killing ability.

Table 1: Refer to the chart below to see a list of common indications for specific antibiotic classes:

Drug Classes for Antibiotics:

Penicillins: Among some of the first types of antibiotics this class features drugs like penicillin, ampicillin, amoxicillin, and methicillin. Over-time it became evident that many pathogens would develop resistance to these medications which helped contribute to the creation of penicillins with beta-lactamase inhibitors which are equipped with the ability to fight bacterial resistance mechanisms.

• MOA: Penicillins work by interfering with the synthesis of bacterial cell walls – eventually leading to lysis.
• Adverse Effects:
  • Hypersensitivity: Anaphylaxis, rash, fever, wheezing
  • GI upset: Nausea, vomiting, diarrhea
  • Superinfections
• Warnings
  • Requires dosage reductions in renal impairment (piperacillin, ampicillin)
• Nursing Considerations:
  • Screen clients with claimed allergies for true hypersensitivity reactions (e.g. rash, wheezing, anaphylaxis) ensuring the client did not just have an adverse effect (e.g. diarrhea, nausea, vomiting). Adverse effects do not result in a contraindication to this class of medications.
    • Monitor pulmonary function and for signs of allergic reaction.
  • Clients should be instructed to complete the full antibiotic regimen to encourage eradication of infection and discourage resistance.
  • Most penicillins can be taken with food to mitigate GI symptoms.

• Common Key Generics (Brands): 
  • Penicillin G (IV)
  • Penicillin VK (oral)
  • Nafcillin, oxacillin
  • Ampicillin, Ampicillin-sulbactam (Unasyn)
  • Amoxicillin (Amoxil), Amoxicillin-clavulanate (Augmentin)
  • Piperacillin, piperacillin-tazobactam (Zosyn)

Cephalosporins: Modeled off penicillins – cephalosporins have become among the most common antibiotics used today in various settings. There are currently five generations of cephalosporins that are classified based on their spectrum of activity.

• MOA: Similar mechanism compared to penicillins – cephalosporins fall under the beta-lactam classification.
• Adverse Effects:
  • Hypersensitivity: Clients with true penicillin allergies develop reactions with cephalosporin usage. As cephalosporin generations increase the risk of allergic reactions to people with penicillin allergies decreases.
  • GI upset: Nausea, vomiting, diarrhea
  • CNS: Headache, dizziness
  • Nephrotoxicity
  • Superinfections
• Precautions:
  • Ceftriaxone should not be reconstituted or mixed with a calcium-containing product (e.g. Ringer’s or Hartmann’s solution) due to risk of precipitation in the lungs or kidneys
• Nursing Interventions:
  • Screen for true penicillin allergies – ensuring a real hypersensitivity reaction.
  • Monitor pulmonary function and for signs of allergic reaction.
  • Generally safe in pregnancy.
  • Monitor renal function
  • Potential interaction with anticoagulants → bleed risk

• Common Key Generics (Brands): 
  • 1st Gen: Cefazolin, cefadroxil, cephalexin (Keflex)
  • 2nd Gen: Cefoxitin, cefprozil, cefuroxime
  • 3rd Gen: Ceftriaxone, cefixime, ceftazidime, cefpodoxime, cefdinir, ceftriaxone (Rocephin)
  • 4th Gen: Cefepime (Maxipime)
  • 5th Gen: Ceftaroline

Tetracyclines: Semisynthetic antibiotics derived from a structure found in a common soil mold. Main examples include minocycline, doxycycline, and tetracycline.

• MOA: Inhibit protein synthesis → inhibition of bacterial cell growth.
• Adverse Effects:
  • Not pregnancy safe
  • Teeth discoloration
  • Sun sensitivity
  • Weakening of skeletal bone structure
  • Hepatotoxicity
• Warnings:
  • Tetracyclines given to children under the age of 8 can cause permanent tooth discoloration if given for prolonged courses.
  • Accumulation of antibiotics can occur in fetal bone and teeth in pregnancy
  • Risk of hepatotoxicity in pregnant women
• Nursing Interventions:
  • Consult on increased sensitivity to light – avoid excessive sun exposure or use sunscreen
  • Avoid antacids and multivitamins with this medication
  • Interaction with birth control – caution with oral contraceptives; additional birth control may be needed
• Common Key Generics (Brands): 
  • Minocycline (Minocin)
  • Doxycycline (Doryx, Periostat)
  • Tetracycline
  • Tigecycline

Macrolides: This class of medications is often prescribed as an adjunctive therapy with other antibiotics. Examples includes erythromycin, clarithromycin, and azithromycin.

• MOA:  Interferes with protein synthesis in susceptible bacteria inhibiting bacterial cell growth.
• Adverse Effect:
  • QT prolongation
    • Monitor ECG
    • Avoid other QT prolonging drugs including fluoroquinolones
  • Hepatotoxic
  • N/V since taken with empty stomach
• Warnings:
  • Practice caution when using these medications as the suffix “mycin” exists in other drug classes such as tobramycin which is an aminoglycoside.
  • Renal dosing adjustments required for clarithromycin
  • QT interval prolongation – increased risk of torsade de pointes
• Contraindication:
  • Azithromycin in clients with a history of cholestatic jaundice or hepatic dysfunction
• Nursing Interventions:
  • Monitor for signs of QT prolongation and risk of atrial fibrillation
  • Monitor ALT and AST
  • Should be taken on an empty stomach
• Common Key Generics (Brands): 
  • Azithromycin (Zithromax)
  • Clarithromycin (Biaxin)
  • Erythromycin (Ery-Tab)

Fluroquinolones: Very broad-spectrum antibiotics capable of treating a wide array of infections. However, increasing safety concerns regarding adverse effects in elderly may discourage use of these medications. Examples of these medications includes ciprofloxacin (Cipro), levofloxacin (Levaquin), and ofloxacin (Floxin).

• MOA: Interference with DNA enzymes that are required for the growth of bacterial cells.
• Adverse Effects:
  • GI: Nausea, vomiting, diarrhea
  • CNS: Headache, dizziness
  • Risk for tendinitis and tendon rupture in elderly and in renal impairment
  • Photosensitivity – avoid long exposure to sun or use sunscreen
  • Neurologic effects (e.g. headache, dizziness, altered mental status)
  • Peripheral neuropathy
  • Risk of aortic aneurysm → dangerous bleeding and death
  • QT prolongation
• Warning:
  • The use of these medications should be restricted to severe-complicated infections
  • Increased risk of toxicity (e.g. tendon rupture, QT prolongation) in elderly
  • Avoid use in clients with aortic aneurysms and those with risk factors for aneurysms including peripheral atherosclerotic vascular diseases, advanced age, and hypertension.
  • Avoid during pregnancy – use safer alternatives when able
  • Risk of musculoskeletal toxicity in children
  • Avoid in clients with myasthenia gravis – as macrolides may precipitate neuromuscular-blocking activity
  • Increased risk of C. difficile – clients on extended periods of these medications should be given probiotics to reduce risk
• Nursing Interventions: 
  • Avoid in pregnancy and lactation
  • Monitor for signs and symptoms QT prolongation, tendon rupture, and bleeding in elderly and renally impaired clients
  • Avoid with antacids or multivitamins as these may reduce the efficacy of the antibiotic increasing resistance
  • Ensure all the medication is taken to discourage resistance
• Common Key Generics (Brands): 
  • Ciprofloxacin (Cipro)
  • Gemifloxacin
  • Levofloxacin (Levaquin)
  • Moxifloxacin
  • Ofloxacin (Floxin)

Aminoglycosides: These medications exhibit profound nephrotoxic and ototoxic properties which limits its use in practice to more severe infections. Examples include tobramycin, gentamicin, neomycin, and amikacin.

• MOA: Powerful antibiotics which demonstrate bactericidal inhibition of protein synthesis – particularly gram-negative bacteria.
• Adverse Effects:
  • Ototoxicity (tinnitus, vertigo, irreversible deafness)
  • Renal toxicity
  • GI: Nausea, vomiting, diarrhea
  • Heart palpitations
  • Hypersensitivity
• Warnings:
  • High risk of nephrotoxicity and ototoxicity – careful monitoring should be in practice when clients are on these medications
  • Risk of neuromuscular blockade is rare but serious – caution with myasthenia gravis
• Nursing Interventions:
  • Avoid with preexisting hearing loss due to ototoxic effects
  • May worsen herpes or mycobacterial infections
  • Renal toxicity (monitor Scr for increases > 1)
  • Avoid in pregnancy and lactation
  • Ensure properly dose by monitoring trough levels periodically
• Common Key Generics (Brands): 
  • Amikacin (Amikin)
  • Gentamicin
  • Neomycin
  • Streptomycin
  • Tobramycin (Tobrex)

Vancomycin: A very commonly used medication prescribed empirically for the treatment of a variety of infections – especially those that are suspected to be gram-positive or containing MRSA. Vancomycin is like aminoglycosides in adverse effects and dosing. This medication is often dosed based on the measurement of trough vancomycin concentrations in the serum.

• MOA: Inhibition of cell wall synthesis leading to decrease in bacterial cell growth – bactericidal in most gram-positive bacteria.
• Adverse Effects:
  • Thrombophlebitis when given too quickly, given via PICC line as preferred route
    • Watch for pain, redness and swelling
  • Red man’s syndrome
    • Severe hypotension
    • Flushing
    • Pruitis on face, neck, and extremities = too fast infusion
      • At least over > 60 minutes
  • Nephrotoxic
  • Ototoxic
  • Anaphylaxis → administer EPI
    • Hives
    • Angioedema
    • Wheezing
    • Trough level check 15-30 minutes before admin
      • Range 10-20
    • Watch for signs of toxicity
• Warnings:
  • Renal dose adjustments in renal impairment (refer to hospital procedures)
  • Do not infuse more than 5 mg/mL in concentration in less than 60 minutes – to avoid infusion-related reactions
  • Risk of extravasation and thrombophlebitis – ensure proper needle or catheter placement prior to infusion
  • Neutropenia with prolonged use
  • High risk of superinfection
  • Formulations containing polyethylene glycol (PEG 400) or N-acetyl D-alanine (NADA) not recommended for use in pregnancy due to risk of fetal malformations
• Nursing Interventions:
  • Dosing based on trough levels – check 15-30 minutes prior to administration of antibiotics
    • Moderate infections: Trough goal = 10-15
    • Severe infections: Trough goal = 15-20
  • Trough is usually drawn before the 4th or 5th dose
    • Initial loading dose is based on clients’ weight
  • Infuse bolus slowly over an hour to avoid adverse effects
  • Nephrotoxic monitor for the following
    • Scr > 1.3 = Bad for kidney
    • BUN > 20
    • Urine output < 30 ml/hr or less = kidney in distress
• Common Key Generics (Brands): 
  • Vancomycin (Vanco)

Sulfonamides: Used to be a highly utilized class of antibiotics but has fallen out of favor due to higher risk of hypersensitivity as well as a less favorable adverse effect profile. The primary example in use is sulfamethoxazole trimethoprim (Bactrim).

• MOA: Inhibition of folic acid synthesis which are precursors for RNA and DNA synthesis → inhibiting bacterial cell growth
• Adverse Effects:
  • Hypersensitivity: Contraindicated when a known or suspected sulfa allergy is present (including allergies to sulfa containing drugs e.g. sulfonylureas, thiazides)
  • GI: Nausea, vomiting, diarrhea
  • Renal: Crystalluria
  • CNS: Headache, dizziness
  • Bone marrow depression
  • Photosensitivity, rash
• Warnings: 
  • Risk of serious hypersensitivity reactions – screen for sulfa allergies
  • Blood dyscrasia – fatalities associated with severe reactions including agranulocytosis and aplastic anemia
  • Hepatic necrosis
  • Hyperkalemia – caution in clients with heart conditions
  • Hypoglycemia – caution in diabetics
  • Risk of thrombocytopenia
• Nursing Interventions:
  • Screen for true sulfa allergies – monitor for signs and symptoms of hypersensitivity
  • Can take with food with upset stomach
  • Not safe for pregnancy
  • Nephrotoxic monitor for the following
    • Scr > 1.3 = Bad for kidney
    • BUN > 20
    • Urine output < 30 ml/hr or less = kidney in distress

Example NCLEX^® Question for NCLEX^® Pharmacology Review of Antibiotics:

Key Nursing Tips for Antibiotics:

Infectious disease proves to be among the most challenging fields to understand when practicing in the medical field. This NCLEX^® Pharmacology Review of Antibiotics hopefully serves as a good overview of the many drugs and disease states that will be encountered frequently in practice. Below is a list of key nursing interventions to keep in mind when practicing in this field.

• Watch for interactions between certain medications with birth control (e.g. penicillins, and tetracyclines)
• Double check before administration in pregnancy and lactation
• No food when taking macrolides, tetracyclines, or fluoroquinolones (generally okay to take with food for penicillins and sulfonamides)
• Avoid or limit alcohol consumption with antibiotics
• Monitor troughs for aminoglycosides and vancomycin
• Monitor kidney function
• Screen for risk of true allergies – understand the difference between adverse effects or allergies (rash, wheezing, dyspnea, swelling, etc.)

Another core concept to infectious disease involves antibiotic resistance. Resistance is a growing concern in the microbiological world as bacteria have been repeatedly found to demonstrate the capacity to develop mechanisms which fight back against antibiotics. This is especially true for penicillins with microbes that develop the ability to destroy the antibiotic before it can reach its target. For this reason, it is crucial that practitioners understand that under dosing or overusing antibiotics can lead to resistance. This limits the selection of antibiotic agents that will therefore be effective against specific pathogens like MRSA which is a highly resistant strain of Staphylococcus bacteria.

Conclusion for Antibiotics:

The field of infectious disease is vast and complex – yet continues to grow and expand in ways that will continue to influence medical practice for years to come. There is a lot to know and understand when it comes to antibiotics and the various disease states used to treat them. Initially the level of information to know for this subject may appear daunting but over-time it should become more familiar, especially with practice.

Before administering antibiotics there are many different interventions nurses can make to ensure the safety of their clients. Screening for allergies, kidney function, pregnancy status, and for the specific microbials selected for the infection are all key interventions for medical teams to implement into their daily practice. It is imperative to have a general understanding of the various classes and nursing considerations to help prepare for the NCLEX^® exam and for future practice.

Example NCLEX^® Question for NCLEX^® Pharmacology Review of Antibiotics:

References:

1. Gaynes R. The Discovery of Penicillin—New Insights After More Than 75 Years of Clinical Use. Emerging Infectious Diseases. 2017;23(5):849-853. doi:10.3201/eid2305.161556.
2. UpToDate. https://www.uptodate.com/contents/penicillin-antistaphylococcal-penicillins-and-broad-spectrum-penicillins. Accessed April 3, 2020.
3. UpToDate. https://www.uptodate.com/contents/cephalosporins. Accessed April 3, 2020.
4. UpToDate. https://www.uptodate.com/contents/tetracyclines. Accessed April 3, 2020.
5. UpToDate. https://www.uptodate.com/contents/Azithromycin and clarithromycin. Accessed April 3, 2020.
6. UpToDate. https://www.uptodate.com/contents/Fluroquinolones. Accessed April 3, 2020.
7. UpToDate. https://www.uptodate.com/contents/Aminoglycosides. Accessed April 3, 2020.
8. UpToDate. https://www.uptodate.com/contents/Vancomycin: Drug information. Accessed April 3, 2020.
9. UpToDate. https://www.uptodate.com/contents/Trimethoprim-sulfamethoxole (co-trimoxazole): Drug information. Accessed April 3, 2020.

Introduction to Blood Thinners

Anticoagulation is an essential service that is frequently provided in the healthcare field to a wide variety of clients. Blood thinners are clinically used for many reasons, including prophylaxis for surgery, arrhythmia conversion, and for clients in a hypercoagulable state. These medications are available in many different types of classes including warfarin, direct-oral anticoagulants (DOACs), heparin, aspirin, and PGy12 inhibitors. It is essential to develop a firm understanding of the different kinds of anticoagulants to prepare yourself for your future practice. This NCLEX^® Review of Blood Thinners is designed to provide you a good overview of the various topics that may appear on the exam.

Indications for Blood Thinners

• Treatment of acute ischemic stroke and transient ischemic attack (TIA)
• Treatment of deep vein thrombosis (DVT)
• Treatment of venous thromboembolism (VTE)
• Treatment of pulmonary embolism (PE)
• Treatment of myocardial infarction and acute coronary symptoms
• Prophylaxis for surgical and elective procedures at high risk of clotting
• Atrial fibrillation rhythm correction (cardioversion) prophylaxis
• Anticoagulation for states associated with increased risk of clot (e.g. severe infections, cancer)

Types of Drugs for Class of Blood Thinners

Warfarin

• MOA:
  • Vitamin K antagonist → deactivates coagulation factors II, VII, IX, and X which are vitamin K dependent.
  • Protein C and S also deactivated.
• Side Effects:
  • Bleeding: Warfarin increases the risk of bleeding which can lead to serious and sometimes fatal bleeding. This can contribute to major hemorrhages in the brain or elsewhere in the body causing death. Increased bleed risk is associated with INR values that are generally > 2.5.
  • Hepatitis
  • Hypersensitivity: Anaphylaxis
  • Acute renal failure
• Warnings:
  • Black Box Warning: Warfarin can cause major or fatal bleeding. Perform regular monitoring of international normalized ratio (INR). Drugs, dietary changes, and other factors can affect INR.
• Nursing Considerations:
  • Key counseling point:
    • It is important to take these medications exactly as the prescriber has instructed – failure to do so may lead to difficulty maintaining a therapeutic INR.
    • Inform clients that changes in diet can alter their risk of bleeding and/or clotting.
    • When taking warfarin, try to eat a consistent diet as INR fluctuations are very likely following the consumption of certain foods.
    • This includes foods high in vitamin K (e.g. leafy green vegetables) that can reduce the anticoagulation effect (↑ clot risk).
    • Certain drugs can alter INR including chewing tobacco, oils, ethanol, and green tea.
    • Prescription drugs may also alter INR so consult with the pharmacy prior to warfarin initiation.
  • INR monitoring:
    • Essential for clients being treated with warfarin. Goal INR range usually between 2-3.
    • INR values > 3 puts clients at increased risk of bleeding
    • Elevated INR is usually managed by giving clients Kcentra (4F-PCC) or vitamin K via oral or parenteral route.
    • INR values > 10 often warrant emergency care.
• Common Key Generics (Brands)
  • Warfarin (Coumadin, Jantoven)

Heparin and Low Molecular Weight Heparin (LMWH)

• MOA:
  • Binds to antithrombin and indirectly deactivates coagulation factors by enhancing the effect of antithrombin.
• Side Effects:
  • Increased risk of major bleeding – intracranial hemorrhage and GI bleeding
  • Heparin-induced thrombocytopenia (HIT)
  • Skin reactions
  • Osteoporosis with long-term use
• Warnings:
  • Increased risk of major bleeding including intracranial hemorrhage as well as gastrointestinal bleeding. Use with caution in clients suspected of having a high risk of bleeding or those who are actively bleeding.
  • Heparins can cause heparin-induced thrombocytopenia (HIT). This is an immune mediated collapse in platelet count that can be serious and potentially fatal – drastically increasing the risk of serious bleeding. This reaction is rare but should be monitored carefully in all clients – especially clients using heparin products for the first time.
• Nursing Considerations:
  • Key counseling points:
    • Increased risk of thrombocytopenia with these medications – counsel clients on increased risk of bleeding which can suddenly progress to a severe state.
    • At home regimens involving low-molecular weight heparins should be taken exactly as instructed to ensure adequate anticoagulation.
  • Monitor platelet count (thrombocytes) at baseline and periodically after to assess for the possibility of thrombocytopenia.
  • Low molecular weight heparins are injected subcutaneously – commonly used in clients following surgical procedures but growing out of favor given the superior safety profile of DOACs.
  • Heparins can be reversed with a medication called protamine.
  • Fondaparinux is a synthetic heparin which has a lower risk of HIT compared to unfractionated heparin and LMWH
• Common Key Generics (Brands)
  • Unfractionated Heparin
  • LMWH
    • Enoxaparin (Lovenox)
    • Dalteparin (Framin)
  • Fondaparinux – synthetic heparin

Direct Thrombin Inhibitors

• MOA:
  • Direct thrombin inhibitor → binds and deactivates thrombin to stop the coagulation cascade.
• Side Effects:
  • Risk of major bleeding – including intracranial hemorrhage and gastrointestinal bleeding
• Warnings:
  • Increased risk of major bleeding including intracranial hemorrhage as well as gastrointestinal bleeding. Use with caution in clients suspected of having a high risk of bleeding or those who are actively bleeding.
• Nursing Considerations:
  • Key counseling point:
    • Dabigatran is the only oral version of these medications – the others are only administered via parenteral route.
    • No risk of heparin-induced thrombocytopenia
    • Dabigatran toxicity can be reversed via Idarucizumab (Praxbind)
  • These medications are generally reserved for heart attacks and strokes – less frequently used than alternative anticoagulants (e.g. heparin, LMWH, DOACs)
• Common Key Generics (Brands)
  • Bivalrudin
  • Argatroban
  • Desirudin
  • Dabigatran (Pradaxa) – oral direct thrombin inhibitor

Direct Oral Anticoagulants (DOACs)

• MOA:
  • Direct factor Xa inhibitors → prevents the cleaving of prothrombin to thrombin halting the coagulation cascade.
• Side Effects:
  • Risk of bleeding
• Warnings:
• Increased risk of major bleeding including intracranial hemorrhage as well as gastrointestinal bleeding. Use with caution in clients suspected of having a high risk of bleeding or those who are actively bleeding.
• Nursing Considerations:
  • Key counseling point:
    • Emphasize the importance of proper adherence to these medications as this can lead to inadequate anticoagulation and/or increased risk of bleeding.
    • Xarelto (rivaroxaban) should be taken with food to ensure proper absorption.
  • These drugs are excreted through the kidneys. Use with caution in clients with renal dysfunction – poor renal function may warrant dosage reduction or changing to another anticoagulant.
  • These medications require much less monitoring and have less risk of serious bleeding when compared to warfarin.
  • These medications can be reversed with Andexanet alfa (AndexXa) in the event of major bleeding
• Common Key Generics (Brands)
  • Apixaban (Eliquis)
  • Rivaroxaban (Xarelto)
  • Edoxaban (Savaysa)
  • Betrixaban (Bevyxxa)

P2y12 Inhibitors

• MOA:
  • Irreversibly blocks the P2Y12 component of ADP receptors on the platelet surface → preventing platelet aggregation
• Side Effects:
  • Increased risk of bleeding (minor and major hemorrhage)
• Contraindication:
  • Contraindicated in clients with active bleeding including peptic ulcers and intracranial hemorrhage
• Nursing Considerations:
  • Key counseling point:
    • Take these medications exactly as instructed to ensure proper anticoagulation.
    • Inform your provider if there are any changes to your medications as they can interfere with these medications.
    • These medications are generally used as addons to other anticoagulants for those who are at very high risk of clotting. They increase the anticoagulation effect by acting on a different mechanism than heparins, warfarin, and DOACs by acting as platelet inhibitors.
    • Cangrelor is only administered via intravenous route – will be seen more in the hospital setting.
• Common Key Generics (Brands)
  • Clopidogrel (Plavix)
  • Prasugrel (Efient)
  • Ticagrelor (Brilique)
  • Cangrelor (Kengreal)

Aspirin

• MOA:
  • Inhibits thromboxane A2 to prevent platelet aggregation
• Side Effects:
  • Increased risk of bleeding (especially gastrointestinal)
  • Risk of peptic ulcer formation
  • Hypersensitivity (anaphylaxis)
  • Rash
  • Agitation
• Warnings:
  • This medication is an NSAID – avoid in clients with proven NSAID allergies
  • Avoid these medications in the elderly (> 70 years)
  • Aspirin should never be used in clients under the age of 18
• Nursing Considerations:
  • Key counseling points:
    • The normal dosage of aspirin used is 81mg – this is called low-dose aspirin
    • These medications can be harsh on the stomach – avoid in peptic ulcer disease
  • No longer used for primary prevention – in clients who have not yet had a major CV event (e.g. MI, TIA, stroke)
  • Low-dose aspirin is often referred to as “baby aspirin” – healthcare providers should avoid this label as it can result in children and infants being given this medication mistakenly.
• Common Key Generics (Brands)
  • Asprin (Bayer)

Key Nursing Tips for Blood Thinners

• Monitor for signs and symptoms of bleeding with all these medications:
  • Clinical findings:
    • ↓ hematocrit
    • ↓ red blood cells
    • ↓ hemoglobin
  • Physical findings:
    • Bloody stools
    • Blood in urine
    • Bruising
• Prior to initiating anticoagulants in clients – assess baseline clotting factors, INR, or for signs and symptoms of bleeding prior to administration.
• Clients on warfarin should be counseled on avoiding significant dietary changes (especially those that contain a lot of vitamin K; e.g. green leafy vegetables)
• Many of these medications are renally excreted – initiate anticoagulants with caution in clients with chronic kidney disease.
• All anticoagulants should be taken as prescribed to ensure proper anticoagulation and to avoid the risk of major bleeding.

Example NCLEX^® questions for NCLEX^® Review of Blood Thinners:

Conclusion for Blood Thinners

Anticoagulants are used frequently and for a wide variety of indications in clients every day in the healthcare setting. They are commonly used for surgical prophylaxis to prevent the risk of serious clotting as well as in clients who have experienced major CV events (e.g. heart attack, stroke), or in clients at high risk of serious clotting. The different classes come with an array of safety profiles – with DOACs being among the safest to administer in most healthy adults. Major bleeding is the primary adverse effect to monitor for in all clients on anticoagulants. Hopefully, this NCLEX^® Review of Blood Thinners served as a nice overview of the different classes and types of blood thinners used clinically today.

References

1. Warfarin: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
2. Garcia D, Crowther M. Management of bleeding in clients receiving direct oral anticoagulants. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
3. Hull R, Garcia D, Burnett A. Heparin and LMW heparin Dosing and adverse effects. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
4. Leung L. Direct oral anticoagulants (DOACs) and parenteral direct-acting anticoagulants: Dosing and adverse effects. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
5. Clopidogrel: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.
6. Aspirin: Drug Information. In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2020. www.uptodate.com. Accessed April 21st, 2020.

Introduction to Beta-blockers

Beta blockers are a commonly used class of medications for clients with cardiovascular disease which is why you should review this NCLEX^® Pharmacology Review of Beta-blockers. The most prescribed indication is hypertension in clients who have either tachycardia (HR > 100 bpm) or in clients with hypertension that was not reduced after initiating other blood pressure medications (e.g. ACE inhibitors, ARBs). Other common indications includes atrial fibrillation or for general anxiety disorders where the goal is to slow the heart rate in response to stress.

Beta blockers are all named with the suffix “lol” or “olol” which helps when trying to memorize this class of medications

Indications for Beta-blockers

• Hypertension: Decreased heart rate and force of contraction → decreased blood pressure and cardiac output.
• Atrial fibrillation and cardiac arrhythmia: Reduces heart rate preventing the heart from beating too quickly leading to serious cardiac events (e.g. myocardial infarction).
• Angina and myocardial infarction: Decreased heart rate reduces the cardiac demand in the heart preventing ischemia and serious damage to the heart tissue.
• Anxiety: Decreased heart rate and sympathetic (fight or flight) activity on the heart – reduces the spread of norepinephrine to the brain and body.

Types of Beta-blockers

MOA: They work by blocking beta receptors in the central nervous system which slows the heart rate and contractility of the heart. These essentially work by acting against sympathetic nervous system, the “fight or flight” mechanisms in your body, by preventing the ability for norepinephrine and epinephrine to increase heart rate and force of contraction during times of stress. By blocking this effect these medications lead to a reduction of heart rate (negative chronotropic) and force of contraction (negative inotropic) which leads to a decrease in resistance, workload, and cardiac output.

Adverse Effects: Beta blockers differ on account of its selectivity for beta 1 receptors in the body. Blockers that are not cardio selective may cause blockade of other beta receptors including receptors in the lungs. This can lead to exacerbations in asthmatic clients or in those with COPD as beta 2 blockade causes constriction of the bronchioles in the lungs. One way to remember this is to understand that albuterol – a commonly prescribed bronchodilator for asthma and COPD – is a beta 2 agonist (meaning it activates beta 2 receptors). Antagonism of the beta 2 receptors can cause the opposite effect, constricting the bronchioles in the lungs making it difficult for clients to breath.

It is also important to note that some beta blockers may affect alpha receptors which can yield other physiological effects further reducing blood pressure. Alpha 1 blockade prevents the constriction of the smooth muscle in arterioles – meaning it widens the arteries to allow for less resistance. This leads to a further reduction of blood pressure but a higher risk of severe hypotension including orthostatic hypotension.

Other Adverse Effects: 

• CV: It is imperative to assess baseline blood pressure and heart rate prior to giving beta blockers to clients. Those with bradycardia (HR < 60 bpm) or systolic blood pressure (SBP < 100 mmHg) should avoid using beta blockers. Further decreasing heart rate can lead to serious hypotension and risk of low blood perfusion.
• Pulmonary: As mentioned above – usage of non-selective blockers in client with reactive airway diseases should be strictly avoided to reduce the risk of bronchospasm.
• Heart failure exacerbations: Edema, pulmonary crackles, weight gain
• Hypoglycemia masking effect: Clients who are diabetic may fail to recognize symptoms of hypoglycemia – masked by the beta blockers.
• Orthostatic hypotension: Increased risk of falls – when going from sitting to standing
• Decreased energy with exertion: Clients may observe lower energy as HR falls – this effect tends to go away through time.
• Beta blocker withdrawal: Acute withdrawal from beta blockers can lead to morbidity and mortality – can cause exacerbation of ischemic symptoms and precipitation of a myocardial infarction or tachyarrhythmia. This is due to upregulation of sympathetic stimulation.
• Depression, fatigue, sexual dysfunction: Common side effects resulting from a reduced effect of norepinephrine on the heart causing lower energy.

Warnings:

• Caution with heart failure clients as beta blockade can lead to worsening of congestive heart failure and significant negative chronotropy
• Avoid giving clients beta blockers with bradycardia (HR < 60 bpm)
• Clients on chronic beta blockers should be slowly titrated off the medication to prevent beta blocker withdrawal
• Overdose can lead to life-threatening bradycardia

Table 1: Common Key Generics (Brands) – with selectivity chart 

Example NCLEX^® questions for NCLEX^® Pharmacology Review of Beta-blockers:

Key Nursing Tips for Beta-blockers:

Beta-blockers are a commonly prescribed medication indicated for an array of disease states. These are often safe medications but may be dangerous when given in certain populations. Reviewing this NCLEX^® Pharmacology Review of Beta-blockers should aid in preparing for the NCLEX^® and general practice for clients requiring these medications.

• Clients with pulmonary conditions (e.g. asthma, COPD) should only be prescribed beta 1 selective blockers (refer to Table 1)
• Monitor for bradycardia or hypotension – hold the blocker if HR drops below 60 or SBP < 100
• Monitor for edema (weight gain, pulmonary crackles, swelling in periphery, JVD)
• Monitor blood glucose of hypoglycemia – suggest increased frequency in blood glucose testing in diabetics who have poorly controlled blood sugar.
• Beta blockers should be titrated off slowly if there is a need to discontinue the therapy – to avoid withdrawal

Conclusion for Beta-blockers:

Beta-blockers are a very commonly prescribed class of medications indicated for a variety of treatment. They are used primarily for cardiovascular diseases as well as arrhythmias including atrial fibrillation. Generally, these medications are safe and well tolerated but may require careful consideration prior to giving medications for specific populations. Clients with a history of reactive airway disease, diabetes, or serious bradycardia conditions should only be given beta blockers with extreme caution.

Reviewing the NCLEX^® Pharmacology Review of Beta-blockers should provide a strong overview of the various considerations that should be in place prior to using these in practice. A firm understanding of how this work as well the potential side effects should aid in studying for the NCLEX^® exam as well as preparation for daily practice.

Example NCLEX^® question for NCLEX^® Pharmacology Review of Beta-blockers:

References:

1. Whelton PK, Carey RM. The 2017 American College of Cardiology/American Heart Association Clinical Practice Guideline for High Blood Pressure in Adults. JAMA Cardiology. 2018;3(4):352. doi:10.1001/jamacardio.2018.0005.
2. UpToDate. https://www.uptodate.com/contents/Major side effects of beta blockers. Accessed April 3, 2020.
3. UpToDate. https://www.uptodate.com/contents/Atenolol: Drug information. Accessed April 3, 2020.
4. Mann SJ. Redefining beta-blocker use in hypertension: selecting the right beta-blocker and the right client. J Am Soc Hypertens. 11(1):54-65. doi:10.1016/j.jash.2016.11.007.
5. Jabbal S, Lipworth BJ. Sensitivity of Lung Resistance and Compliance to Beta-Blocker Induced Bronchoconstriction and Long Acting Beta-Agonist Withdrawal in COPD. Lung. 196(1):15-18. doi:10.1007/s00408-017-0079-1.
6. Prijic S, Buchhorn R. Mechanisms of Beta-Blockers Action in Clients with Heart Failure. Rev Recent Clin Trials. 2014;9(2):58-60. doi:10.2174/1574887109666140908125402.
7. Prins KW, Neill JM, Tyler JO, Eckman PM, Duval S. Effects of Beta-Blocker Withdrawal in Acute Decompensated Heart Failure: A Systematic Review and Meta-Analysis. JACC. 3(8):647-653. doi:10.1016/j.jchf.2015.03.008.