Impact of catecholamines in cardiac arrest due to acute asphyxia--a study in piglets.

Abstract

Early intravenous epinephrine administration may help to achieve return of spontaneous circulation in cardiac arrest (CA). However, venous access can be challenging in small children. This study investigates the effect of intravenous and intramuscular epinephrine in treatment of asphyxial CA. Twenty-eight, 2-5-weeks-old, anesthetized piglets were asphyxiated by ventilation withdrawal. CA was untreated for 8min, followed by 2min of basic life support. Following this, epinephrine iv (10μg·kg(-1) , group IV), epinephrine im (100μg·kg(-1) , group IM), or normal saline (group NS) were administered. Further doses of epinephrine were given in group IV every 4min, in group IM after 10min if required. After twenty-two minutes of CA, iv epinephrine was given to all animals still in CA. Outcome measures were survival and epinephrine plasma concentrations. Ten animals regained spontaneous circulation after 2min of basic life support. Therefore, no drug treatment was administered (drop out). Resuscitation was effective in 2 pigs of group IM (n=6), in 6 of group NS (n=8) and in all of group IV (n=4). Nonsurvivors had higher epinephrine (P<0.01) and norepinephrine (P<0.01) plasma concentrations prior to start of resuscitation. Median increase in epinephrine plasma concentration from T0 to T5 was 138, 134, and 29nm in group IV, IM, and NS, respectively. Intravenous and intramuscular administered epinephrine led to similar increase in plasma concentrations during resuscitation of asphyxial CA without hemodynamic or survival benefit. High endogenous epinephrine and norepinephrine plasma concentrations were negative predictors for survival.