What is the indication for vasopressin in CPR?
Vasopressin, also known as antidiuretic hormone, is a potent vasoconstrictor when used at higher doses.
Vasopressin’s vasoconstrictive effect increases blood flow to the brain and heart during CPR. The vasoconstrictive effect is mediated via V1 receptors and thus independent of the adrenergic-receptor-mediated effect of epineph-rine. Therefore, vasopressin seems to lack some of the β-adrenergic- mediated adverse effects of epinephrine, such as increased myocardial oxygen demand and tachycardia. Vasopressin currently holds a Class IIb recommendation in the treatment for pulseless VT/VF. It is not yet recom-mended for asystole and pulseless electrical activity, mainly because large studies showing improved outcome are still missing. Thus, vasopressin is currently recommended as a first-line alternative to epinephrine in patients with pulse-less VT/VF, given as a single dose of 40 U i.v. push. Because of the longer half-life of vasopressin (10–20 minutes) compared with epinephrine (3–5 minutes), and lack of supportive evidence in human trials, a second dose is not recommended at this point. Following vasopressin admin-istration and 10–20 minutes of continued CPR without the return of a perfusing rhythm, it is acceptable to return to 1 mg epinephrine every 3–5 minutes.