What is the optimal dose of epinephrine during cardiopulmonary resuscitation in a rat model?
OBJECTIVE
Because different species may require different doses of drug to produce the same physiologic response, we were provoked to evaluate the dose-response of epinephrine during cardiopulmonary resuscitation (CPR) and identify what is the optimal dose of epinephrine in a rat cardiac arrest model.


METHODS
Rat cardiac arrest was induced via asphyxia, and then the effects of different doses of epinephrine (0.04, 0.2, and 0.4 mg/kg IV, respectively) and saline on the outcome of CPR were compared (n = 10/each group). The primary outcome measure was restoration of spontaneous circulation (ROSC), and the secondary was the change of spontaneous respiration and hemodynamics after ROSC.


RESULTS
Rates of ROSC were 9 of 10, 8 of 10, 7 of 10, and 1 of 10 in the low-dose, medium-dose, and high-dose epinephrine groups and saline group, respectively. The rates of withdrawal from the ventilator within 60 minutes in the low-dose (7 of 9) and medium-dose epinephrine groups (7 of 8) were higher than in the high-dose epinephrine group (1 of 7, P < .05). Mean arterial pressures were comparable, but the heart rate in the high-dose epinephrine group was the lowest among epinephrine groups after ROSC. These differences in part of time points reached statistical significance (P < .05).


CONCLUSIONS
Different doses of epinephrine produced the similar rate of ROSC, but high-dose epinephrine inhibited the recovery of spontaneous ventilation and caused relative bradycardia after CPR in an asphyxial rat model. Therefore, low and medium doses of epinephrine were more optimal for CPR in a rat asphyxial cardiac arrest model.
Chen
Meng-Hua
MH
Institute of Cardiovascular Diseases, the First Affiliated Hospital of Guangxi Medical University, Nanning, PR China. cmhnn@sina.com
Lu
Jun-Yu
JY
Xie
Lu
L
Zheng
Jun-Hui
JH
Song
Feng-Qing
FQ
D000818:Animals; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004837:Epinephrine / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D018709:Statistics, Nonparametric
D004837:Epinephrine