Pulmonary gas exchange after cardiopulmonary resuscitation with either vasopressin or epinephrine

Objective: It is well established that epinephrine administered during cardiopulmonary resuscitation results in pulmonary. gas exchange disturbances. It is uncertain how vasopressin affects gas exchange after cardiopulmonary resuscitation. Design: Prospective, randomized experimental study. Setting: Animal research laboratory. Subjects: Twenty domestic pigs. Interventions. Animals were subjected to ventricular fibrillation and cardiopulmonary resuscitation by using either vasopressin or epinephrine. Hemodynamic and pulmonary gas exchange (multiple inert gas elimination technique) variables were recorded before cardiopulmonary resuscitation and 10, 30, 60, and 120 mins after return of spontaneous circulation when either epinephrine (control) or vasopressin was used. Measurements and Main Results: At 10 mins after return Of spontaneous circulation, blood flow to low V-A/Q lung units was increased in animals treated with epinephrine (17.8 +/- 6 vs. 2.6 +/- 3%, mean So, P <.01). Resulting carbon dioxide elimination was impaired in animals treated with epinephrine but not in animals treated with vasopressin (Paco(2), 55 2 vs. 46 4 torr, p <.05). Thirty minutes after return of spontaneous circulation, blood flow to lung units with a normal V-A/Q ratio was reduced in animals treated with epinephrine (79 +/- 1 vs. 84 +/- 12%, p <.05), resulting in a depressed Pao(2) (147 +/- 4 vs. 127 +/- 10 torr, p <.05). Conclusion: Vasopressin compared with epinephrine for cardiopulmonary resuscitation resulted in better gas exchange variables in the early postresuscitation phase.