Emergency Pharmacology: A Highlight on Vasopressors (Dopamine)

Vasopressors are life-saving drugs that are commonly seen in an emergency setting. But what are vasopressors, and what are their mechanisms of action?

Vasopressors Defined

Vasopressors are types of medications that exert pressure on the veins, on the vascular beds to promote vasoconstriction. When this happens, there is an increase in blood flow to the heart, lungs, and the brain. Aside from these organs, the kidneys are also directly affected by vasopressors.

Upon administration of vasopressors, the kidneys are alerted to hold all the fluid in the body or what is also known as fluid retention, causing dilation in the renal cavity or arteries; this will be explained further as we go along.

Examples of Vasopressors

There are many examples of vasopressors available in the market, but there are only two that are commonly utilized inside the hospital, especially in emergency scenarios. These drugs are:

  • Norepinephrine (Levophed)
  • Dopamine

Between the two, we’ll focus our attention on dopamine.

Dopamine

Dopamine is usually the first line of drug given to anyone who is suffering from hypotension.

Much like any other vasopressors, the introduction of dopamine is going to prompt vasoconstriction, putting pressure on the vessels. The primary goal for the administration of dopamine is to increase blood pressure. Aside from boosting blood pressure, dopamine can also inadvertently increase heart rate.

As mentioned, the kidneys are also going to be affected through perfusion, holding the fluid in to retain blood and distribute it to the rest of the body.

Hypotensive Crisis

Vasopressors are given especially during a hypotensive crisis. A hypotensive crisis is a situation wherein the body is losing a lot of blood drastically, which can either be caused by the following:

  • Trauma, example: gunshot wound
  • Excessive vomiting
  • Diarrhea

Any of these events can lead to hypovolemic shock, which is a deficiency of blood or fluids within the vascular spaces. If there is the extremely low amount of blood perfusion, it will compromise the distribution of oxygen. Remember, without oxygen, the body will eventually expire.

The Function of the Kidneys

So, during a hypotensive crisis, the kidneys will swoop in to save what is left of the little blood in the body by ceasing the mechanism of urination. The kidneys will not allow pee to go out of the body, keeping it inside the vascular spaces until blood pressure will rise naturally.

Route of Dopamine

Dopamine is usually given with an intravenous infusion as a piggyback or slow infusion; this will help increase blood pressure and dilate the renal arteries. This is true during emergencies.

Dopamine and ARF

Dopamine is also given to clients who are suffering from acute renal failure (ARF). When the kidneys are failing, dopamine will ignite the opening up of the renal arteries, causing more perfusion by shunting blood down to the kidneys so the client won’t go into chronic renal failure, and potentially losing the kidneys.

How does one determine that there is low perfusion in the kidneys?

The mean arterial pressure (MAP) determines how much blood flow is getting around the body. Normally the MAP is from 85 – 100. However, if there are problems with the kidneys, the MAP will go below 65. If this happens, the perfusion becomes compromised. To prevent this, dopamine is given.

For our next lecture, we’ll be focusing on the second vasopressor we’ve mentioned – norepinephrine (Levophed). Check it out in Simple Nursing’s website and YouTube channel.

Nervous System Anatomy and Physiology: Pharmacologic Reactions

This lecture is a continuation of our previous nervous system’s anatomy and physiology. In this piece, we will go through the involvement of sympathomimetic and parasympathomimetic drugs to the peripheral nervous system.

As a quick review, the nervous system is primarily composed of the following:

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)

The peripheral nervous system is broken down into two parts, mainly:

  • Sympathetic nervous system
  • Parasympathetic nervous system

Sympathetic Nervous System

The sympathetic nervous system, also known as the fight or flight response, is related mainly to stress. This means that when stimuli trigger the sympathetic nervous system, the following occurrences, which are also signs of stress, are bound to happen:

  1. Increased heart rate
  2. Increased respiratory rate

Parasympathetic Nervous System

The parasympathetic nervous system, also known as the rest and digest response, is the opposite of the sympathetic nervous system. This is basically what happens when the body is not going into overdrive or utilizing the sympathetic nervous system.

The parasympathetic nervous system’s functions are:

  • Slows down the heart rate
  • Stimulates gastrointestinal activities
  • Relaxes the muscles of the urinary and excretory system

The Teeter-Totter Effect

Remember that the sympathetic nervous system and the parasympathetic nervous system are opposites, acting like a teeter-totter wherein, if one is turned on, the other is turned off automatically.

Sympathomimetic versus Parasympathomimetic

The sympathomimetic and parasympathomimetic drugs are like nicknames for the sympathetic and parasympathetic nervous system drugs, emulating their functions and actions inside the body.

The Sympathomimetic Drugs

Sympathomimetic drugs are sympathetic nervous system stimulants, jumpstarting the heart and lungs to increase their rates; thereby, boosting oxygen supply to numerous parts of the body and inducing better breathing.

Epinephrine is a typical example of a sympathomimetic drug. Epinephrine is adrenaline utilized in hospital settings, especially in emergency rooms.

The Parasympathomimetic Drugs

When the body is given parasympathomimetic drugs, other organs will be prioritized, and the following will happen:

  • Increased digestion
  • Increased mucus production
  • Increased blood flow to different organs

This means that there will be a cholinergic effect that can lead to better perfusion to the mucous membranes, gastrointestinal tract, and kidneys.

SNS and Adrenaline

Loading up adrenaline to a client will shunt blood to the two vital organs of the body – the heart and lungs. Blood pressure will shoot up, squeezing blood from the extremities to make sure that distribution will be focused on the system that matters most during distressing situations.

However, there are side effects that are expected to happen, namely:

  • Dry mouth
  • Constipation
  • Urinary retention
  • Confusion
  • Drowsiness

Hospital Scenario

A client who is in cardiac arrest comes into the emergency room. The health team is pumping the heart to perfuse the body. Are you going to give a parasympathomimetic or sympathomimetic drug?

To sustain life, the heart and lungs need to have adequate perfusion. Therefore, epinephrine and dopamine have to be given to raise the blood pressure and pulse, and shunt the required blood to the heart and lungs.

In our next discussion, we’ll be talking about agonist, adrenergic agonist, and antagonists.

Dopamine & Epinephrine: Emergency Meds

For the last two drugs included in the acronym, Sax Fifth Avenue when dealing with chronotropic, inotropic, and dromotropic drugs, we have dopamine and epinephrine.

Dopamine

Dopamine has a lot of effects on the body.

Dopamine directly affects blood pressure and is also considered as a vasopressor. Vasopressors put pressure on veins, specifically the vascular space, to bring back blood into the heart and lungs.

Dopamine is also potent in helping with renal perfusion by opening the renal tubules and allowing perfusion in the kidneys. Dopamine is extremely helpful for clients experiencing acute renal failure.

Dopamine is also an inotropic drug because it helps with forceful heart contractions.

Digoxin vs. Dopamine

Digoxin is also an inotropic drug; however, it is more focused on atrial fibrillation, specifically on targeted on the atrial kick. As for dopamine, it is more on perfusion. By being a vasopressor, dopamine presses on the veins to bring blood back to the heart and push all that oxygenated blood out to the rest of the system.

Dopamine Indications

Dopamine is usually given to clients who are extremely hypotensive or low blood pressure to facilitate proper flow of oxygen. Since oxygen is the money that makes the body go around, having extremely low blood pressure can be detrimental because oxygen is not appropriately distributed to different areas of the body. Dopamine helps in situations like this.

Dopamine as an Inotropic Drug

Not all drugs are negative chronotropic. Dopamine is an inotropic drug that increases the heart rate to increase blood pressure and oxygen perfusion. The goal is to increase the amount of oxygen in the red blood cells, specifically the hemoglobin, to carry them out to the different parts of the body.

Epinephrine

Dopamine and epinephrine are somehow similar but different. How?

Epinephrine pretty much has the same qualities of dopamine with regards to having a positive inotropic effect, which helps the heart contract. Epinephrine also has a positive chronotropic effect in increasing the heart rate. Lastly, epinephrine is also known as adrenaline, which is a sympathomimetic drug that mimics the sympathetic nervous system.

Fight and Flight

A sympathomimetic response or a fight and flight response is when the body increases the heart rate to increase blood flow to the heart, lungs, and brain. However, with epinephrine, it is done differently; there is no pressure acted on the vessels to increase perfusion. Instead, epinephrine acts like a hormone that stimulates the fight and flight response.

You can say that this approach is just one of many different routes, and is useful and effective in bringing the heart rate up and contracting more forcefully.

Different Approach

Giving emergency drugs is like being locked out of the house; there are a couple of ways to go in, and you will still get the same result of being able to get in. Whether you’re trying to decrease blood pressure or heart rate, it can be done with the ABC drugs. On the other hand, if the goal is to increase the pressure, heart rate, and perfusion, you can choose from inotropic, chronotropic, and dromotropic drugs.

Acute Renal Failure: Nursing Management & Interventions Pt 2

Part one of our discussions on acute renal failure nursing management, we focused on two interventions – Kayexalate and Dopamine. These two belong to the four nursing processes that are required to manage acute renal failure. To easily remember, you can think of the acronym – HDTV. H stands for hyperkalemia while D stands for dopamine.

In this lecture, we will tackle the remaining two processes – T and V.

Before discussing the remaining two interventions, we’ll quickly go through the first two.

Kayexalate for Hyperkalemia

Kayexalate is the first thing that is given to acute renal failure clients due to the presence of hyperkalemia. Hyperkalemia is just one of the complications of having acute renal failure, and the only way to get it out of the body is through the potty which involves urination and fecal excretion. If urine is not being produced due to acute renal failure, potassium will be expelled through the anus with the help of Kayexalate.

Dopamine

Dopamine helps in renal vasodilation and at the same time, vasoconstricting the peripheral body, causing an increase in pressure. Low blood pressure is one of the main causes of acute renal failure; therefore, dopamine will help in the hyperperfusion of the kidneys.

The T and V

Now, the last two types of intervention are a bit difficult to comprehend because both are concerned with volume.

So, the main goal is to push volume through the kidney which can be referred to as, “tickling the kidney.” Tickling the kidney simply means increasing the perfusion which will lead to increased blood volume and oxygen. By doing so, we’re trying to get the client from the oliguric phase to the diuretic phase in the hopes that the condition will eventually lead to the recovery phase.

After giving dopamine to dilate the blood vessels in the kidneys, fluid is then pushed into the diuretic phase. This is where the T and V come in.

Total Volume

Giving total volume or a bolus of IV fluid means giving more fluid to the client; much like pouring fluid with the use of IV normal saline.

The kidneys are similar to washer machines. Imagine if these washer machines have too much accumulation of mud and are broken. By dilating the renal arteries and pushing more volume, we are restarting the organ and are getting rid of the mud inside the washer machines.

Volume Depletion

Diuretics are given to make sure that the kidneys are receiving sufficient volume. This is what we refer to as the volume depletion stage. Since the primary goal is to get fluid going into the kidneys and have it restarted, diuretics will push the volume through the kidneys. Lasix (Furosemide), the most popular loop diuretic, is a potassium-depleting medication given to acute renal failure clients.

A Summary

In retrospective, when a client in an oliguric phase, the kidneys are not working, and the basic goal is to achieve a diuretic phase. This is done by increasing the amount of perfusion in the kidneys through an IV bolus. Diuretics are given to make sure that there is enough volume that is being pushed inside the kidney to have it restarted and enter the diuretic phase. Once the client’s kidneys are rebooted, the next goal is to achieve the recovery phase.

In our next lecture, we will talk about creatinine clearance tests and how it is connected to clients with renal failure.

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Neurological Disorders: What is Parkinson’s Disease? – Part 1

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Parkinson’s disease is a progressive disorder that is primarily focused on the body’s dopamine production. It is not about the body attacking itself like that of multiple sclerosis or myasthenia gravis.

What happens in Parkinson’s disease?

Parkinson’s disease, much like ALS, is a progressive disorder that is just a fancy word for the continuous cessation of creating a substance primarily involved in the condition. In the case of Parkinson’s disease, the body has stopped making dopamine.

No dopamine, what does it mean?

Dopamine is a potent neurotransmitter that helps in controlling the brain’s pleasure and reward centers; it signals or transmits messages across the synapses. When dopamine is decreased or absent in the body, messages do not get relayed which will result in a central nervous system breakdown regarding motor function and dexterity of the muscles.

“No Dope in the Park”

Remember this phrase when you are trying to recall what Parkinson’s disease is.

When there is decreased dopamine or none at all, there’s “no dope in the park” because of the progressive nature that directly affects the brain’s communication with major parts of the body.

Signs and Symptoms

As a nurse, how are you going to fix the decrease in dopamine?

Well, there are a whole bunch of drugs that one can give to stimulate dopamine increase but before we discuss the kinds of drugs, we’ll first focus on the signs and symptoms and deviate a bit on how to diagnose Parkinson’s disease.

With all your other type of diseases, you have diagnostics like withdrawing certain chemicals from the body then sending it to the lab to be checked. With multiple sclerosis, there will be certain pathogens that will be present in the sample which creates an immune response, attacking the myelin sheath. A lumbar puncture and a CAT scan are done to assess how much of your body is creating this immune response to itself.

However, with Parkinson’s disease, diagnosis is based on the neurological signs and symptoms which mainly comprise of:

  1. Progressively slow movements
  2. Rigidity or freezing while walking
  3. Shuffling gait
  4. Pill rolling
  5. Expressionless face, like wearing a mask
  6. Balance problems – dopamine is one of those neurotransmitters that helps in maintaining the brain’s equilibrium
  7. Tremors (shaking)

One of the tests done to diagnose someone with Parkinson’s disease is to have the client write anything – their name or a line from a song. Once the client starts to write, their penmanship will be normal at first, but as the writing goes on, the letters will become progressively smaller. This is what experts use to diagnose Parkinson’s disease.

Nurse Considerations

What can you do as a nurse to help your client with Parkinson’s disease? It’s the regular things – exercise and diet.

Losing weight, breaking a sweat, or exercising release dopamine. Though this is not a definitive cure, it can help in producing dopamine that can lessen the abovementioned signs and symptoms; but since this condition is progressive, exercise is just a control measure. Passive range of motion exercises can prevent joint stiffness.

Another nursing consideration that you have to wolteach to your client is to eat healthily. Consuming foods that are high in antioxidants – green tea and veggies – as well as foods that are high in fiber and low in sugar will slow the progression of Parkinson’s disease. So, diet and exercise are the two main things that you can ask your client to do.

For your Parkinson’s disease drugs, they will be discussed in our next lecture.

Drop by SimpleNursing.com for a wide range of nursing topics that will help with your study habits and pass the NCLEX®.

See you on our next Parkinson’s disease discussion!

Acute Renal Failure: Nursing Management and Interventions

Before discussing the therapeutic modalities of acute renal failure, we’ll be tackling a bit about your prerenal and intrarenal.

So, this is basically a quick review of your prerenal and intrarenal BUN level with regards to your creatinine. You just have to remember the following:

  • Prerenal = big BUNs = BUN-creatinine ratio is 20:1
  • Intrarenal = small BUNs = BUN-creatinine ratio is 10:1

When talking about nursing interventions of your kidneys, regarding acute renal failure, which do you think is more serious – prerenal or intrarenal?

Prerenal Acute Kidney Failure

Mike has stated that prerenal acute kidney failure is when the fire is outside the house, which means that the fire is not inside the kidneys nor is it affecting the nephrons just yet. Therefore, in prerenal, urine is still being created so there will still be urine output.

Even if the specific gravity of the urine would be very concentrated, brown, and stinky, there would still be some urine being excreted by the body.

Intrarenal Acute Kidney Failure

On the other hand, intrarenal acute kidney failure presents no pee-pee (urine output) because the “fire” is inside the kidneys affecting the structures within and mainly causing damaging effects to the kidneys.

So, that’s basically how you can easily distinguish prerenal from intrarenal acute kidney failure.

Nursing Intervention – HDTV

Regardless of what you’re thinking, HDTV does not stand for high definition television. Instead, HDTV here stands for:

  • H – Hyperkalemia
  • D – Dopamine
  • T – Total volume (increased)
  • V – Volume excess (decreased)

What does this mean in terms of your nursing process?

Hyperkalemia

During your oliguric phase, urine is not created, or if urine is being created, the body is not getting rid of it. Therefore, potassium must be increased. However, since potassium is a potent electrolyte, increased potassium can cause increased contraction that may result to dysrhythmias. Thus, hyperkalemia happens.

In providing nursing interventions, one must always remember that the first thing that needs to be addressed is what’s detrimental to your client. And since increased potassium can severely affect the client’s heart, it should first be managed.

You have to give attention to hyperkalemia first by bringing down the potassium level using Kayexalate. Kayexalate helps in getting rid of excess potassium from the body.

Since the body is unable to urinate, potassium will exit the body through the feces. So one side effect that you have to watch-out-for when giving Kayexalate is episodes of diarrhea.

Hyperkalemia > Kayexalate > Gets rid of excess potassium > poo-poo (feces) > diarrhea

Dopamine

Dopamine is used to dilate the renal arteries to get more blood down to the kidneys, causing:

  • More perfusion
  • More pressure
  • More oxygen
  • Increased blood flow to heart, lungs, and kidneys

Technically, when you give dopamine to your client, you wanted to increase the mean arterial pressure (MAP) to cause increased perfusion, thus also increasing the oxygen level.

On part two of our discussion, we will be talking about the T (total volume) and the V (excess volume). It’s just as simple as increasing the total volume while decreasing the excess volume.

Drop by simplenursing.com for the continuation of this discussion.

See you there!

Psychiatric Pharmacology Made Easy – Part 1

One of the biggest topics in nursing school is psychiatric pharmacology. Here at SimpleNursing.com, we breakdown every single vital information and present it to you in the simplest possible way.

Before going into the drugs that are primarily used for psychiatric clients, we will first tackle the pathophysiology. You have to keep in mind that before you know the mechanism of each type of drug, you must first know what it affects.

So, let’s get into it.

Psychiatric medications affect three major neurotransmitters in the body, namely:

  1. Dopamine
  2. Serotonin
  3. Norepinephrine

Reminder: Dopamine and serotonin are your reward and happiness hormones.

Dopamine

According to nursing books, dopamine inside the brain is for reward, pleasure, motor function, and compulsion. To easily remember all these, remember DOP. It basically stands for:

D – Determination (motivation)

O – Obsession (addiction to drugs like cocaine, methamphetamine, stimulants)

P – Pleasure (reward)

Frontal cortex of the brain is mostly affected by dopamine as a neurotransmitter.

Reminder: Dopamine for the rest of the body is different from dopamine inside the brain.

Basic concept to remember

The brain has a filter, like that of brewing a coffee, which is technically called as the blood-brain barrier (BBB). This BBB filter prevents chemicals and toxic elements to enter the brain to avoid unwanted consequences like the brain shutting down. Think of the BBB as a border patrol or security that doesn’t allow anything and everything to enter the brain.

Serotonin

This is your happy hormone. Serotonin can be best remembered by thinking of Siri, the iPhone application who basically makes you happy because she can answer any kind of question. In the nursing book, serotonin is referred to as your mood, sleep, cognition, and memory. Forget the book and just remember SER:

S – Sleep

E – Emotion

R – Remember

Basic concept to remember

Inside the brain, serotonin first affects the hippocampus and then it goes all the way around the brain, sort of like a racetrack. To remember that serotonin acts on the hippocampus, you can just think of a huge hippo with a bunch of knowledge, walking around campus.

Norepinephrine (Levophed)

Norepinephrine is primarily seen in MAOI drugs and atypical antidepressants. It is the same category as epinephrine (adrenaline) which is also called as noradrenaline or your stress hormone. Stress hormones trigger the body’s sympathetic nervous system (SNS) that then activates the increase in heart rate and blood pressure and the fight and flight mechanisms. If your SNS is activated, your parasympathetic nervous system (PNS), also known as your rest and digest, is automatically deactivated which means that you will be unable to produce gastric juice that is used for digestion and your bowel movement.

So, to remember ALL that, you can associate norepinephrine with NOR:

N – No hesitation

O – On alert

R – Recall memory

Basic concept to remember

Hypertension is a huge qualifier for norepinephrine, especially with MAOI. Also, one must take into consideration the cognitive alertness of a person. Example, a person is going into septic shock or any kind of shock for that matter, norepinephrine is immediately given.

As what Mike’s instructor said, “You use Levophed or you leave him dead.” This is because norepinephrine (Levophed) is the last line of drugs to get increase blood pressure, squeeze in and vaso-press (vasopressor) all the blood back into the vital organs or your SNS (heart, brain, lungs), urgently supplying them with oxygen.

Mike’s study tip

Get three note cards. Separately write down DOP, SER, and NOR on each note card. Copy the acronyms provided by Mike or what he likes to call “memory tricks.” Put in all information for the specific acronym. For example, for the DOP card, put in its equivalent meanings and what it mainly affects in the body.

What do you put at the back? It’s going to be further explained on the next video. So stay tuned!

For the meantime, SimpleNursing.com has created its first psychiatric course called Psychiatric 101. Here, Mike focuses on the struggle points which are the areas where students usually fail. What are these struggle points?

  1. NCLEX®-style questions
  2. Pharmacology

Psychiatric 101 is mainly created to help students pass and clear their understanding of the topics then retaining it fully. Mike will help you breakdown the biggest issues on psychiatric nursing and pharmacology. Just visit our website and be a member of our diamond and annual plans to request videos or have live webcam streaming for lectures.

Check it out!