In the 2000 algorithm, vasopressin was an important addition, although not actively promoted by a pharmaceutical company. It was then recommended as a Class 2B medication for pulseless VT/VF. In stark contract, epinephrine is “class Indeterminant.”

The dose of Vasopressin is 40 given IV/IO x 1, returning to epinephrine. In the laboratory model of cardiac arrest, the combination of vasopressin and epinephrine works better in cardiac arrest than either Vasopressin or Epinephrine alone.

Vasopressin was a “new drug” in the 2000 Guidelines. Originally investigated by Dr. Lindner of the University of Ulm in Germany and Dr. Keith Lune, of the University of Minnesota, they published a small case series in 1997, which described 8 patients who responded to 8 IU vasopressin after the failure of conventional ACLS failed.

Studies in animal models that the combination of vasopressin and epinephrine significantly improved coronary blood flow in dog models of arrest. A preliminary randomized control trial, using 40IU Vasopressin, was published in Lance in 1997. Early results showed that a significantly larger number of V fib patients treated with epinephrine were resuscitated successfully from out-of-hospital ventricular fibrillation, with survival to 24 hours. Cardiovascular research suggested that vasopressin improved vital organ blood flow, cerebral oxygen delivery, resuscitatibility and better neurologic outcome improvements in animal studies.

A large study in German, Austria, and Switzerland next began to test the treatment with vasopressin vs. epinephrine, and in the interim, both the CPR guidelines of the AHA and the European Resuscitation Council recommended vasopressin 40 IU IV as equally effective for the treatment of adult patient in ventricular fibrillation. In vasodilatory shock, continuous infusions of vasopressin (0.04 to 0.01 U/min) stabilized cardiocirculatory parameters, and assisted with weaning of catecholamines. An observational cohort study found that patients receiving vasopressin had a greater return of spontaneous circulation with higher admission to the hospital. Additionally, the hospital discharge rate was significantly higher in patients treated with vasopressin.

During CPR, vasopressin significantly improves total cerebral and left heart flow, causing a sustained increase in Mean Arterial Pressure when compared with

maximal doses of epinephrine. Conclusions of this randomized controlled study with a primary end point to survival, followed by survival to hospital discharge, enrolled 1219 patients. Analysis of the results revealed that the effects of vasopressin in the management of ventricular fibrillation and pulseless electrical activity. Vasopressin was superior to epinephrine in patients with asystole, and vasopressin followed by epinephrine was found to potentially be more effective than epinephrine alone

in treatment of refractory cardiac arrest.

Recap: When to use vasopressin:

-Substitute 40 IU IV/IO for the first or second dose of epinephrine in cardiac arrest. This may be more effective than epinephrine alone in treatment of refractory cardiac arrest.

-Vasopressin is superior to epinephrine in asystole.