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.