Vasopressors, Inodilators, Inopressors, Pure Vasopressors, Methylene Blue, Midodrine Flashcards
What is the effect of dobutamine on stroke volume?
Increases stroke volume
What should be monitored when titrating dobutamine and milrinone?
Echocardiogram, urine output, central venous pressure
What happens to beta receptors with prolonged dobutamine use?
They undergo desensitization and efficacy decreases.
What is a pro of using dobutamine?
It is easily titratable.
What is a downside of dobutamine in patients with atrial fibrillation?
It increases heart rate, which may worsen atrial fibrillation.
How does milrinone compare to dobutamine?
Milrinone has a greater vasodilatory effect than dobutamine.
What is a downside of milrinone in patients with chronic kidney disease?
It can accumulate and cause significant negative effects.
What is a major downside of isoproterenol?
It is extremely expensive.
What are inopressors used for?
They increase contractility, stroke volume, cardiac output, and blood pressure.
What are some examples of inopressors?
Norepinephrine, epinephrine, and dopamine.
What is a concern with using dopamine?
It is generally not favored due to its side effects.
What is norepinephrine primarily known for?
Strong alpha 1 receptor agonist activity and beta 1 receptor agonist activity.
What type of receptors does epinephrine primarily act on at lower doses?
Beta 1 and beta 2 receptors.
What happens to epinephrine’s activity at higher doses?
It becomes an alpha 1 receptor agonist while retaining beta agonist activity.
What is the primary activity of dopamine at lower doses (1-4)?
Dopamine receptor type activity, leading to mild increase in cardiac output and vasodilatory effects.
What effects does dopamine have at doses of 4-10?
Increased beta receptor stimulation, leading to increased heart rate and cardiac output.
What occurs with dopamine at doses of 10-20?
Increased alpha receptor activity, raising systemic vascular resistance.
What are the risks associated with dopamine use?
Difficult to titrate, higher mortality rates, and potential gut malperfusion.
What is a significant adverse effect of dopamine extravasation?
High risk of tissue necrosis.
What is a key indication for using angiotensin II?
Septic shock or vasodilatory shock.
What is the effect of stimulating alpha-1 receptors?
Increased vascular resistance and blood pressure.
What do alpha-1 receptors stimulate?
Norepinephrine and epinephrine stimulate alpha-1 receptors.
Where are alpha-1 receptors present?
Alpha-1 receptors are present on arterioles and venules.
What happens when alpha-1 receptors on arterioles are stimulated?
It clamps down on arterioles, increasing systemic vascular resistance and blood pressure.
What is the effect of stimulating alpha-1 receptors on venules?
It increases venous vasoconstriction, raising preload and cardiac output.
What is the effect of beta-1 receptor stimulation?
It increases heart rate and contractility, thus increasing cardiac output.
What does epinephrine act as?
Epinephrine is a beta agonist, specifically a strong beta-2 agonist.
What is the effect of epinephrine on the lungs?
Epinephrine causes bronchodilation, similar to albuterol.
How does epinephrine affect mast cells?
It inhibits mast cells from releasing histamine, reducing bronchospasm.
What effect does epinephrine have on lactate production?
Epinephrine increases lactate production in the liver.
What is the relationship between stroke volume and cardiac output?
Increasing stroke volume leads to an increase in cardiac output.
What are the primary indications for norepinephrine and epinephrine?
Septic shock and cardiogenic shock are primary indications for norepinephrine and epinephrine.
Which drug is considered first-line for septic shock?
Norepinephrine is the first-line drug for septic shock.
How do norepinephrine and epinephrine affect cardiac output in cardiogenic shock?
They can increase heart rate and contractility, improving cardiac output in cardiogenic shock.
Which drug provides more beta-1 activity in cardiogenic shock?
Epinephrine provides more beta-1 activity compared to norepinephrine in cardiogenic shock.
What is a common add-on treatment for cardiogenic shock?
Dobutamine or milrinone are common add-on treatments for cardiogenic shock.
What role does epinephrine play in bradycardia?
Epinephrine can help increase heart rate in patients with bradycardia.
What is a preferred treatment for severe bradycardia?
Transcutaneous pacing and atropine are preferred treatments for severe bradycardia.
What is push-dose epinephrine used for?
Push-dose epinephrine is used to stabilize patients who are becoming bradycardic or in asystole.
What is a potential drug for bradycardic periarrest patients?
Epinephrine infusion or push-dose epi.
What is the dose of intramuscular epinephrine for anaphylaxis?
0.5 milligrams every five minutes, up to three doses.
What is the acceptable MAP goal in shock patients?
Greater than or equal to 65 mmHg.
What does MAP stand for?
Mean Arterial Pressure.
How is MAP calculated?
Diastolic BP + one third of pulse pressure.
What effect does epinephrine have on the bronchioles?
Causes bronchodilation.
What is the mechanism of epinephrine in anaphylactic shock?
Inhibits mast cell degranulation and causes vasoconstriction.
What is a significant response of epinephrine in anaphylactic shock?
Increases heart rate and blood pressure.
What should be monitored when titrating epinephrine?
Blood pressure, specifically MAP.
What is the target MAP for titrating epinephrine?
Greater than or equal to 65 mmHg
What heart rate can be targeted when titrating epinephrine?
Greater than 50 beats per minute
What is norepinephrine primarily used for?
First line treatment for septic shock
What is a potential downside of norepinephrine in patients with atrial fibrillation?
It may increase heart rate, worsening rapid AFib
What is epinephrine effective for?
Septic shock and cardiogenic shock
What effect can epinephrine have on patients with lung disease?
Bronchodilation effect
What should clinicians monitor when administering epinephrine?
Lactate levels
What does a lactate level greater than or equal to 4 indicate?
Possible lactic acidosis due to tissue perfusion issues
What does epinephrine do to lactate production?
It increases lactate production
What might indicate a patient could respond well to angiotensin II?
Being on a pre-illness ACE inhibitor.
What should be considered when giving epinephrine to a patient with AFib?
It can worsen AFib due to increased beta-1 stimulation
What does an increase in lactate levels indicate regarding tissue perfusion?
An increase in lactate does not necessarily mean poor tissue perfusion; it may be due to beta-2 receptor effects on the liver increasing lactate production.
What are pure vasopressors primarily used for?
Pure vasopressors primarily function to clamp down on peripheral blood vessels.
Name three drugs classified as pure vasopressors.
Phenylephrine, vasopressin, and angiotensin II.
What type of receptor does phenylephrine primarily stimulate?
Phenylephrine primarily stimulates alpha-1 receptors.
How does vasopressin function in the body?
Vasopressin works by stimulating V1 receptors on systemic arterioles and V2 receptors in the kidneys.
What are V1 and V2 receptors associated with?
V1 receptors are associated with peripheral vessels; V2 receptors are associated with kidney tubules.
What is the significance of angiotensin II in vasopressor therapy?
Angiotensin II acts on angiotensin II receptors in arterioles, causing vasoconstriction, but data on its efficacy is still limited.
What happens when alpha-1 receptors are stimulated?
Stimulation of alpha-1 receptors leads to vasoconstriction, increasing systemic vascular resistance.
What is the effect of phenylephrine on arterial and venous vessels?
Phenylephrine binds to receptors on both arterioles and venules, causing them to clamp down and increase systemic vascular resistance.
What happens when you clamp down on the arterials?
Decreases diameter, increases systemic vascular resistance, increases blood pressure, and increases afterload.
How does increasing preload affect stroke volume?
Increasing preload increases stroke volume.
What is the effect of phenylephrine?
Stimulates alpha-1 receptors, causing vasoconstriction and increasing blood pressure.
What receptor does vasopressin stimulate for vasoconstriction?
V1 receptor.
What is the effect of stimulating V2 receptors by vasopressin?
Increases aquaporins in kidney tubules, enhancing water reabsorption.
How does vasopressin increase blood pressure?
By retaining more water from kidneys and causing vasoconstriction.
What does angiotensin II do when it binds to its receptors on systemic arterioles?
Causes vasoconstriction, increasing systemic vascular resistance and blood pressure.
What is the effect of increased aldosterone?
Increases sodium and water reabsorption, raising blood volume and blood pressure.
What role does ADH play in blood pressure regulation?
Stimulates water reabsorption to increase blood volume and blood pressure.
What happens when blood volume increases?
It increases blood pressure and stimulates ADH release.
What does ADH do when released?
It reabsorbs more water, increasing blood volume and blood pressure.
What is the effect of increasing ADH and aldosterone?
It effectively increases blood volume and blood pressure.
What is a common type of vasodilatory shock?
Septic shock.
What is the first-line agent for vasodilatory shock?
Norepinephrine.
What is a second-line agent for vasodilatory shock?
Vasopressin.
What is angiotensin II used for?
It is a last-ditch effort in treatment when other vasopressors fail.
What condition can vasopressin treat in neuro ICU?
Central diabetes insipidus.
What happens when ADH is not released in impending herniation?
Kidneys do not hold water, leading to significant urine output and decreased blood volume.
What can result from excessive dilute urine output?
It can significantly lower blood volume and blood pressure.
What is the effect of producing a lot of dilute urine?
It lowers blood volume and blood pressure significantly.
What does vasopressin do in the body?
It acts on V2 receptors to reabsorb water in the kidneys.
What condition can vasopressin help with in cirrhosis patients?
Hepatorenal syndrome.
How does vasopressin benefit patients with hepatorenal syndrome?
It causes vasoconstriction of efferent arterioles, increasing glomerular pressure and urine output.
When is angiotensin II particularly beneficial?
In patients with septic shock and high renin levels (≥200).
What is a potential response of patients on renal replacement therapy to angiotensin II?
They may experience increased urine output.
What is the appropriate MAP goal for titration of vasopressin?
Greater than or equal to 65 mmHg
When can vasopressin be beneficial?
In septic shock and central diabetes insipidus or hepatorenal syndrome
What is the titration goal for phenylephrine?
MAP greater than or equal to 65 mmHg
What is a pro of phenylephrine in patients with AFib with RVR?
It can cause reflex bradycardia, which is beneficial
What is a potential con of using phenylephrine in patients with low ejection fraction?
It may increase afterload, making it harder to push blood out
What MAP goal should angiotensin II be titrated to?
Greater than or equal to 65 mmHg
What should be monitored when titrating angiotensin II?
Heart function, urine output, MAP, and clinical status
What is the effect of phenylephrine on blood vessels?
It causes vasoconstriction, increasing blood pressure
What is a benefit of phenylephrine for patients with aortic stenosis?
It is suitable due to their fixed afterload
What is a key consideration when using vasopressin?
Expect changes in urine output
What effect does phenylephrine have on preload?
It increases preload, which can increase stroke volume and cardiac output.
In which condition might increasing preload not help?
In severe systolic heart failure with low ejection fraction.
What is a key characteristic of phenylephrine compared to norepinephrine?
Phenylephrine lacks beta-1 activity unlike norepinephrine.
What is a benefit of vasopressin on the efferent arteriole?
It causes vasoconstriction, increasing glomerular hydrostatic pressure and urine output.
How does vasopressin affect pulmonary vessels?
It can cause vasodilation, lowering pulmonary artery pressure.
What is a major risk of extravasation of vasopressin?
It can cause tissue necrosis and digital ischemia.
What potential con is associated with angiotensin II?
It may increase thrombosis and coagulation cascade activity.
What is a potential risk of angiotensin II?
Increased risk of thrombosis and pro-thrombotic state.
What does interleukin-6 contribute to?
Cytokine storm and multi-organ system dysfunction.
What happens when the angiotensin II gene is knocked out in studies?
Lower mortality rates observed.
What type of shock is methylene blue used for?
Refractory vasoplegic shock of any etiology.
Where does methylene blue primarily act?
In vascular smooth muscle.
How does methylene blue affect nitric oxide synthase?
It inhibits nitric oxide synthase, decreasing nitric oxide levels.
What is the effect of low nitric oxide levels on cyclic GMP?
Less nitric oxide leads to lower cyclic GMP levels.
What is the result of low cyclic GMP levels?
Increased calcium levels in the cytoplasm.
What does methylene blue inhibit?
Nitric oxide synthase
What is the effect of methylene blue on cyclic GMP?
It inhibits the conversion of GTP to cyclic GMP
What happens to calcium levels in the cytoplasm when methylene blue is administered?
Calcium levels in the cytoplasm increase
What does increased calcium in the cytoplasm lead to?
Increased contraction of smooth muscle
What is the result of smooth muscle contraction due to methylene blue?
Vasoconstriction
What happens to systemic vascular resistance with vasoconstriction?
It increases
How does methylene blue affect blood pressure?
It increases blood pressure
In which condition is methylene blue beneficial?
Refractory vasoplegic shock
What is the typical dosage of methylene blue?
2 mg/kg
What MAP goal should be targeted when titrating methylene blue?
Greater than or equal to 65
What is a potential negative effect of methylene blue?
Increased pulmonary vascular resistance
How does methylene blue affect pulmonary vessels?
Causes vasoconstriction
What can increased pulmonary vascular resistance lead to?
Increased right ventricular stress
What effect can methylene blue have on oxygen saturation readings?
It can lower oxygen saturation
What unusual reading might a pulse oximeter show after administering methylene blue?
A pulse ox of 52
What effect does methylene blue have on pulse oximeter readings?
It can cause inaccurate readings, showing low oxygen saturation despite proper oxygenation.
What condition can methylene blue potentially cause due to its role as a monoamine oxidase type A inhibitor?
Serotonin syndrome, which can increase blood pressure and heart rate.
How does methylene blue affect patients with G6PD deficiency?
It acts as an oxidating agent, increasing hemolytic anemia and Heinz body production.
What impact does methylene blue have on the cytochrome P450 system?
It inhibits the system, increasing drug concentrations of other medications.
Is it safe to administer vasopressors through a peripheral IV in a crashing patient?
Yes, it is safe for a short period of time, but monitoring is essential.
What should be monitored when administering vasopressors through a peripheral IV?
The peripheral IV site and patient parameters to prevent complications.
Is it okay to run vasopressors through peripheral IVs?
Yes, but ensure the IV is easily monitored and avoid deep ultrasound guided IVs.
What should you monitor for when using peripheral IVs for vasopressors?
Surrounding tissue necrosis and signs of extravasation.
What counteracting agent can be used for extravasation of vasopressors?
Phentolamine can be used against catecholamine vasopressors.
Which vasopressors should be used cautiously with peripheral IVs?
Vasopressin and dopamine should not be used for long periods.
What is the gold standard for administering high-dose vasopressors?
Central venous catheters are the gold standard for high-dose vasopressors.
Which veins are commonly used for central venous access?
Internal jugular, subclavian, and femoral veins are used.
When is it appropriate to use arterial lines with vasopressors?
To get accurate mean arterial pressure measurements in certain patients.
What conditions may warrant the use of arterial lines?
Subclavian stenosis, aortic dissection, or issues with cuff pressures.
Can peripheral IVs be used for low-dose vasopressors?
Yes, using peripheral IVs for low-dose vasopressors is acceptable.
What is an arterial line used for?
To provide a better representation of mean arterial pressure, especially in hypotensive patients.
What is the primary mechanism of action of Midodrine?
It is primarily an alpha-1 receptor agonist causing vasoconstriction.
What does Midodrine increase in the body?
Systemic vascular resistance, blood pressure, preload, stroke volume, and potentially cardiac output.
What are the indications for using Midodrine?
To wean off IV vasopressors and in patients with hepatorenal syndrome.
What did the MIDAS trial conclude about Midodrine?
It is not very effective in weaning off vasopressors, but is still used due to its alpha-1 activity.
What are the cons of using Midodrine?
It is renally excreted and may accumulate in renal dysfunction; can cause reflex bradycardia.
How is Midodrine administered?
Typically started at 10 mg every 8 hours, with titration as needed.
What is a medication to consider when weaning off IV vasopressors?
Metoprolol, starting at 10 mg q8 hours.
What is the maximum dosage of Metoprolol when weaning off vasopressors?
Up to 40 mg q8 hours.
What should be monitored when weaning off vasopressors?
The patient’s underlying renal function.
What risk is associated with Metoprolol in patients with low ejection fraction?
It may stress the heart.
What condition may not respond to an increase in preload?
Severe systolic heart failure.
What topic was discussed in the video?
Vasopressors.
What is the first step in treating severe bradycardia in a patient at risk of cardiac arrest?
Transcutaneous pacing.
What is the goal when starting medications for shock management?
To titrate against specific clinical parameters, not just blood pressure.
What is the potential issue with titrating shock medications against blood pressure?
They have variable effects on blood pressure.
What should dobutamine and milrinone be titrated against?
Cardiac output
What is a common method to measure cardiac output?
Echocardiogram (echo)
What can indicate an increase in cardiac output?
Increased urine output
What is the primary use of isoproterenol?
To increase heart rate
What is a benefit of dobutamine?
Short half-life, easily titratable
What is a downside of long-term dobutamine use?
Beta receptor desensitization
What surrogate measurements can help assess cardiac output?
Central venous pressure, Svo2, lactate levels
How does increased perfusion to the kidneys relate to cardiac output?
It should increase urine output
What is unique about milrinone’s mechanism of action?
It does not involve catecholamines or adrenergic receptors.
What enzyme converts ATP into cyclic AMP?
Adenylate cyclase
What does cyclic AMP stimulate in muscle tissue?
Protein kinase A
What effect does protein kinase A have on cardiac muscle?
Stimulates contraction
What effect does protein kinase A have on smooth muscle?
Causes relaxation
What enzyme does cyclic AMP phosphorylate in smooth muscle?
Myosin light chain kinase
What is the effect of vasodilation on systemic vascular resistance?
Lowers systemic vascular resistance
What enzyme inhibits cyclic AMP?
Phosphodiesterase type 3 (PDE3)
What drug inhibits PDE3 to increase cyclic AMP levels?
Milrinone
What is the effect of milrinone on cardiac output?
Increases cardiac output
What condition can be treated with dobutamine and milrinone?
Cardiogenic shock
What is the effect of vasodilation on blood pressure?
Lowers blood pressure
What happens to the afterload when smooth muscle relaxes?
It lowers the afterload
What is the effect of vasodilation of peripheral vessels on afterload?
It lowers afterload, which can be beneficial.
What condition is characterized by vasodilation and increased capillary permeability?
Septic shock.
What happens to effective arterial blood volume in septic shock?
It is low.
Which drugs are used to increase cardiac output in septic shock with low ejection fraction?
Dobutamine and milrinone.
What is a potential drawback of using dobutamine or milrinone in septic shock?
They may worsen vasodilation and drop blood pressure.
What type of medications are dobutamine and milrinone considered in septic shock management?
Add-ons to vasopressors.
What is isoproterenol used for in patients with bradycardia?
To increase heart rate and stabilize patients before pacing.
What are vasopressors?
Medications that constrict blood vessels and increase blood pressure.
What is the first category of vasopressors discussed?
Inodilators.
What does ‘inotropic’ refer to in inodilators?
Increase in contractility of the heart.
What does ‘dilator’ refer to in inodilators?
Causes vasodilation of peripheral vessels.
What is the primary drug in the inodilator category?
Dobutamine.
What type of receptor does dobutamine primarily act on?
Beta receptors.
What is the primary action of dobutamine?
It is a beta agonist that increases heart contractility.
What is the secondary drug mentioned in the inodilator category?
Milrinone.
What enzyme does milrinone inhibit?
Phosphodiesterase type 3.
What is the third drug mentioned in the inodilator category?
Isoproterenol.
What type of agonist is isoproterenol?
A strong beta agonist.
What effect does stimulating beta 1 receptors have on the heart rate?
Increases heart rate (chronotropic activity).
What is the effect of increased heart rate on cardiac output?
It potentially increases cardiac output.
What is the relationship between cardiac output and stroke volume?
Cardiac output equals heart rate times stroke volume.
Where are beta 1 receptors located in the heart?
On the contractile myocardium, not on the nodal cells.
What effect does stimulating contractile myocardial cells have?
Increases contractility, which increases stroke volume.
How does dobutamine primarily work?
Increases conductive activity, heart rate, and cardiac output.
What is the effect of dobutamine on contractile cells?
Stimulates contractile cells, increasing calcium and contraction.
What type of receptor activity does dobutamine have?
Very little alpha activity and more beta activity.
What happens when alpha 1 receptors are stimulated on peripheral vessels?
Causes vasoconstriction of the blood vessel.
What is the effect of dobutamine on systemic vascular resistance?
It decreases systemic vascular resistance and blood pressure.
What is the effect of beta 2 receptor stimulation by dobutamine?
Causes vasodilation, lowering systemic vascular resistance.
What is afterload in cardiac physiology?
The stress on the heart to pump blood out.
What is isoproterenol primarily used for?
It is a beta agonist that increases heart rate and contractility.
What effect does isoproterenol have on blood pressure?
It may cause a decrease in afterload and blood pressure.
