Final answer:
The correct answer about epinephrine during resuscitation is that it stimulates spontaneous contractions when asystole is present. It is used during cardiac arrest and increases both myocardial oxygen consumption and vascular resistance, contrary to some of the options listed.
Step-by-step explanation:
The correct option : d
Epinephrine is commonly used in cardiac arrest situations, including ventricular fibrillation (v fib). It is not contraindicated in v fib; instead, it is recommended as part of the Advanced Cardiac Life Support (ACLS) protocol by the American Heart Association. Epinephrine acts predominantly on alpha-1 and beta-1 adrenergic receptors, resulting in increased myocardial contractility and heart rate, which are vital during resuscitation. However, contrary to the belief that it reduces myocardial oxygen consumption, it increases it due to the increased heart rate and contractility.
Regarding peripheral vascular resistance, epinephrine actually increases vascular resistance overall through alpha-1 receptor stimulation, though it can cause vasodilation in some vascular beds via beta-2 receptor stimulation. This vasoconstrictive effect increases blood pressure and is crucial in maintaining perfusion during resuscitation. When it comes to asystole, which is the absence of cardiac electrical activity, epinephrine can facilitate the return of spontaneous circulation by stimulating contractions through its action on beta-1 adrenergic receptors, although this effect may not directly initiate contractions in all cases of asystole.