Vasopressin in CA Flashcards
Adrenaline action on alpha 1 receptor?
Arterial vascular smooth muscle -> contraction -> increase in systemic vascular resistance.
Adrenaline action on beta 1 receptor?
Cardiac myocyte receptors -> increases HR and contractility (positive ionotropic and chronotropic)
Adrenaline action on beta 2 receptor?
Vasodilation -> predominantly of blood vessels in skeletal muscles.
Also bronchodilation
Only high-quality study to show adrenaline survival association?
Nakahera et al 2013.
How many studies showed a negative effect of adrenaline?
6
Why might adrenaline be harmful in cardiac arrest?
Mostly it’s beta-1 action: could increase myocardial oxygen demand -> myocardial damage and dysfunction post arrest.
Also:
- Transient hyperaemia from pulmonary artery shunting and impaired microcircultion
Particular worry of adrenaline in acidotic patients?
Ventricular arrthymias (can happen if not acidotic as well)
Example of Vasoconstrictors/vasopressors?
Vasopressin
Examples of vasodilators?
Nitrites
Examples of ioconstrictors?
Adrenaline, noradrenaline and dopamine
Examples of inodilators?
dobutamine and mirinone
MOI of vasopressin?
ADH - in high doses, powerful vasoconstricotr acting via stimulation of smooth muscle V1 receptors.
Act via G-protein coupled mechanism -> increase in intracellular calcium -> smooth muscle contraction -> vasoconstriction in systemic, splanchnic, renal and coronary circulations -> increases perfusion pressures.
Three benefits of vasopressin from animal studies?
Better coronary blood flow, better cerebral blood flow and increased chance of survival with full neurological function
Benefits of vasopressin over adrenaline in CA?
Vasopressin has neither chronotropic or inotropic effects on the heart.
In acidotic patients - better.
