Reversal of vagal tone in conjunction with high-dose epinephrine in a canine asphyxial pulseless electrical activity model.

OBJECTIVE

To investigate the effects of surgical vagotomy in conjunction with high-dose epinephrine (0.2 mg/kg) on return of spontaneous circulation rates in a canine model of asphyxial pulseless electrical activity.

DESIGN

Prospective, controlled laboratory investigation, using an asphyxial canine cardiac arrest model randomized to receive bilateral cervical vagotomy or no vagotomy.

SETTING

Emergency medicine animal research laboratory.

SUBJECTS

Sixteen mongrel dogs weighing 15 to 25 kg.

INTERVENTIONS

Pulseless electrical activity arrest was induced by clamping the endotracheal tube. All animals remained in untreated pulseless electrical activity for 10 mins and then were randomized to receive bilateral cervical vagotomy (n = 8) or no vagotomy (n = 8). All animals received standard external cardiopulmonary resuscitation and high-dose epinephrine (0.2 mg/kg every 5 mins) throughout resuscitation.

MEASUREMENTS AND MAIN RESULTS

The electrocardiogram complex rate, arterial blood gases, and coronary perfusion pressure during resuscitation were not statistically different between groups. Return of spontaneous circulation was achieved in 88% (7/8) of the no vagotomy vs. 63% (5/8) of the vagotomy animals (p = NS). All animals that achieved return of spontaneous circulation survived 1 hr.

CONCLUSIONS

In conjunction with high-dose epinephrine, vagotomy did not improve the return of spontaneous circulation rate in this pulseless electrical activity arrest model. Additionally, the hemodynamic effects of high-dose epinephrine overshadowed the effects of vagotomy.