Neuroprotective effects of the inhalational anesthetics isoflurane and xenon after cardiac arrest in pigs

Abstract

Neurologic outcome after cardiopulmonary resuscitation from cardiac arrest carries a poor prognosis and treatment options to ameliorate brain damage are limited. Report of two protocols investigating the effects of xenon (Xe) and isoflurane (Iso) in a porcine model of prolonged cardiac arrest and subsequent cardiopulmonary resuscitation on functional neurologic outcomes. Prospective, randomized, laboratory animal study. Male domestic pigs (Sus scrofa). After successful resuscitation from 8 mins of cardiac arrest and 5 mins of cardiopulmonary resuscitation, pigs were randomized to receive either Xe for 1 or 5 hrs in comparison with untreated controls 1 hr after cardiopulmonary resuscitation (protocol 1) or to receive Iso or Xe in comparison with untreated controls 10 mins after cardiopulmonary resuscitation (protocol 2). Animals were exposed to an established cognitive function test and gross neurologic performance was assessed using a neurologic deficit score. In protocol 1, Xe administration resulted in improved early cognitive and overall neurologic function, whereas in protocol 2 there was no significant effect on functional performance. Although Xe conferred functional neurologic improvement even when treatment was delayed for 1 hr, the early treatment with either Xe or Iso translated to only marginal functional improvement.