STANDARD AND HIGHER DOSES OF ATROPINE IN A CANINE MODEL OF PULSELESS ELECTRICAL-ACTIVITY

Objective: To determine whether standard or increased doses of atropin e improve the return of spontaneous circulation (ROSC) rate in a canin e model of pulseless electrical activity (PEA). Methods: A prospective , controlled, blinded laboratory investigation was performed using an asphyxial canine cardiac arrest model. After the production of asphyxi al PEA, 75 dogs remained in untreated PEA for 10 minutes and then were randomized to receive placebo (group 1) or one of four doses of atrop ine (group 2, 0.04 mg/kg; group 3, 0.1 mg/kg; group 4, 0.2 mg/kg; grou p 5, 0.4 mg/kg). All the animals received mechanical external CPR and epinephrine (0.02 mg/kg every 3 minutes) throughout resuscitation. Res ults: The ROSC rates were not significantly different between the grou ps (group 1, 73%; group 2, 67%; group 3, 40%; group 4, 47%; group 5, 2 7%; p = 0.06). The heart rates and hemodynamics during resuscitation w ere not significantly different between the groups. Conclusion: In thi s canine model of asphyxial PEA cardiac arrest, standard-dose atropine did not improve ROSC rates, compared with placebo. Increasing doses o f atropine tended to decrease ROSC rates, compared with placebo and st andard-dose atropine.