Effects of vagal tone on resuscitation from experimental electromechanical dissociation.

STUDY OBJECTIVE

To determine if complete loss of vagal tone improves the return of spontaneous circulation rate in a canine model of electromechanical dissociation cardiac arrest.

DESIGN

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

INTERVENTIONS

After the production of asphyxial electromechanical dissociation arrest, 16 mongrel dogs remained in untreated electromechanical dissociation for ten minutes and then were randomized to receive bilateral cervical vagotomy or no vagotomy. All animals received standard external CPR and epinephrine (0.02 mg/kg every five minutes) throughout resuscitation.

MEASUREMENTS AND MAIN RESULTS

Return of spontaneous circulation was achieved in 13% (one of eight) of no vagotomy and 75% (six of eight) of vagotomy animals (P = .02). Survival to one hour was achieved in 100% (one of one) of no vagotomy and 83% (five of six) of vagotomy animals (P = NS). The hemodynamic and arterial blood gas values at five, ten, and 15 minutes into resuscitation were not significantly different between groups.

CONCLUSION

In this canine model of asphyxial electromechanical dissociation cardiac arrest, surgical vagotomy and complete loss of vagal tone improved the rate of return of spontaneous circulation.