Introduction to Vasopressors
When administered, there is an increase in blood flow to the heart, lungs, and brain. Aside from these organs, the kidneys are also directly affected by vasopressors.
After administering vasopressors, the kidneys are alerted to hold all the fluid in the body (what’s also known as fluid retention), causing dilation in the renal cavity or arteries.
Vasopressors press on the blood vessels, increasing blood pressure to squeeze oxygen-rich blood back to the CORE of the body to perfuse the vital organs (sort of like squeezing a toothpaste bottle).
They work by activating Alpha and Beta receptors inside the heart and blood vessels.
Memory trick
- Alpha 1 = constriction of vessels
- Beta 1 = 1 Heart
- Beta 2 = 2 Lungs
List of Vasopressors
- Epinephrine
- Norepinephrine
- Vasopressin
- Desmopressin
- Dobutamine
- Dopamine
Vasopressors Side Effects
- Headache
- Chest pain
- Fluid in the lungs (pulmonary edema)
- Difficulty breathing
- Slow heart rate (bradycardia)
- Blood clots (thromboembolism)
- Low blood platelets (Thrombocytopenia)
- Fast heart rate (tachycardia)
- Hypertension
- Decreased urinary output
Vasopressor Receptor Chart
| Indication | Alpha 1 | Beta 1 | Beta 2 | |
| Epinephrine | Septic shock & cardiac arrest | BIG | Medium | Small |
| Norepinephrine | Septic shock | BIG | Medium | Small |
| Vasopressin & Desmopressin | Hypovolemic shock | – | – | – |
| Dopamine | Cardiogenic shock | Medium | BIG | Small |
| Dobutamine | Cardiogenic shock | Small | BIG | Medium |
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Epinephrine
Epinephrine is a top choice during cardiac resuscitation, because it has inotropic, chronotropic, and vasoconstrictive effects. It can be used to increase coronary perfusion pressure, which is a major determinant of the return of spontaneous circulation after cardiac arrest.
Epinephrine Mechanism of Action
Epinephrine acts on alpha-1 receptors to cause smooth muscle contraction in the blood vessels, pupil expansion, and contraction of the sphincter muscles of the intestine.
Epinephrine Nursing Considerations & Interventions
Epinephrine is likely to widen pulse pressure. It’s crucial to administer epinephrine as soon as you recognize the signs and symptoms of anaphylaxis.
When implementing airway clearance techniques or respiratory muscle training, take advantage of the maximally bronchodilated state.
Monitor your client’s blood pressure, pulse, and respiratory rate closely after administering an IV.
Norepinephrine
Norepinephrine is a vasopressor with beta activity that maintains mean arterial pressure by increasing systemic vascular resistance after or during appropriate fluid resuscitation. So it’s more suitable than pure alpha-1 agonists in most situations.
Norepinephrine Mechanism of Action
Norepinephrine stimulates alpha-1 receptors to constrict peripheral blood vessels and increase blood pressure.
Norepinephrine Nursing Considerations & Interventions
When giving norepinephrine IV infusions, cardiac monitors should be used on clients. In addition, the defibrillator and resuscitation cart should be close by during infusion.
Monitoring blood pressure and apical pulse continuously during norepinephrine therapy is essential to ensure that the patient remains stable. Also monitor their blood pressure every couple of minutes.
Vasopressin
Vasopressin acts within the brain and in the periphery to modulate blood pressure. It stimulates sympathetic outflow, constricts blood vessels, and increases baroreflex sensitivity and fluid retention in the kidneys.
Vasopressin Mechanism of Action
Vasopressin acts via the kidney to regulate water resorption and on the vasculature to regulate smooth muscle tone. It also acts as a neurotransmitter in the brain, modulating autonomic function.
Vasopressin Nursing Considerations & Interventions
Vasopressors should be prescribed cautiously to pregnant clients and lactating mothers. The drugs can harm the fetus or newborn.
Monitor blood pressure hourly during intravenous infusion and monitor urine output, too. Also use caution with HF and CV disease.
Desmopressin
Desmopressin is a synthetic form of vasopressin. When administered nasally, via IV or orally, it limits the amount of water eliminated in urine and can also be given as a sublingual tablet.
Desmopressin Mechanism of Action
Adenylyl cyclase is stimulated when desmopressin binds to V2 receptors in the basolateral membrane of the distal tubule cells. This then collects ducts of the nephron.
Desmopressin Nursing Considerations & Interventions
Fluid restriction should be observed, and fluid intake should be limited to a minimum from one hour before taking desmopressin until the next morning.
Report upper respiratory tract infections and nasal congestion, and monitor for increased thirst (polydipsia).
Dobutamine
Dobutamine increases the volume of blood pumped by the heart, lowers pressure in the lungs, and decreases resistance in other parts of the body.
It’s especially useful for clients with decompensated systolic heart failure and low cardiac output, but it can also be used in those in whom extreme hypotension is not present.
Dobutamine Mechanism of Action
Dobutamine increases contractility, leading to a smaller end-systolic volume and increased stroke volume.
Dobutamine Nursing Considerations & Interventions
- Educate the client that they will need frequent monitoring while on dobutamine. Also, advise the client to inform the nurse immediately if any chest pain, shortness of breath, numbness, or tingling in their extremities occurs.
- Instruct the client to notify a nurse immediately if pain or discomfort occurs at the injection site.
- Assess for signs of phlebitis, localized pain, redness, or swelling in the affected area.
- Administer appropriate volume expanders to correct hypovolemia (body fluid loss).
Dopamine
Dopamine is usually the first line of drugs given to anyone suffering from hypotension.
Much like any other vasopressors, the introduction of dopamine will prompt vasoconstriction, putting pressure on the vessels. The primary goal of the administration of dopamine is to increase blood pressure.
Aside from boosting blood pressure, dopamine can also inadvertently increase heart rate. 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.
Dopamine Mechanism of Action
When dopamine is released in low doses, it stimulates D1 and D2 receptors in the renal vasculature. This leads to vasodilation and promotes renal blood flow to preserve glomerular filtration.
At intermediate doses, dopamine also stimulates beta 1 receptors in the heart.
Dopamine Nursing Considerations & Interventions
Monitor the client’s blood pressure, pulse, peripheral pulses, and urinary output at intervals.
The dosage of dopamine should be adjusted according to the client’s response, with particular attention paid to the diminution of urine flow rate.
During my exam, I could literally see and hear him going over different areas as I was answering my questions.
This past Friday I retook my Maternity Hesi and this time, I decided for my last week of Holiday break to just watch all of his OB videos. I am proud to say that with Mike’s help I received a score of 928 on my Maternity Hesi!
