Is epinephrine or vasopressin the drug of choice for CPCR?
Vasopressin is a nonadrenergic endogenous peptide that causes potent vasoconstriction via the V1 receptors in the smooth muscle of the vasculature. Its purported benefits over epinephrine include dilatation of cerebral vasculature and less constriction of coronary and renal blood flow. An additional benefit is that this response remains intact in an acidotic environment, such as in CPA, whereas the majority of catecholamines lose most of their vasopressor effects. However, this theoretical benefit was not realized in human trials of pulseless cardiac arrest, as the outcome of patients receiving vasopressin versus epinephrine was the same. In humans with asystole, vasopressin was superior to epinephrine in survival to hospital discharge in some studies.2 The most recent guidelines use these 2 drugs interchangeably and recommend administration of vasopressin to replace the first or second dose of epinephrine in asystole or pulseless electrical activity. See Aids & Resources, back page, f
