Ischemic postconditioning at the initiation of cardiopulmonary resuscitation facilitates functional cardiac and cerebral recovery after prolonged untreated ventricular fibrillation

Abstract

ObjectivesIschemic postconditioning (PC) with “stuttering” reintroduction of blood flow after prolonged ischemia has been shown to offer protection from ischemia reperfusion injury to the myocardium and brain. We hypothesized that four 20-s pauses during the first 3min of standard CPR would improve post resuscitation cardiac and neurological function, in a porcine model of prolonged untreated cardiac arrest. Methods18 female farm pigs, intubated and isoflurane anesthetized had 15min of untreated ventricular fibrillation followed by standard CPR (SCPR). Nine animals were randomized to receive PC with four, controlled, 20-s pauses, during the first 3min of CPR (SCPR+PC). Resuscitated animals had echocardiographic evaluation of their ejection fraction after 1 and 4h and a blinded neurological assessment with a cerebral performance category (CPC) score assigned at 24 and 48h. All animals received 12h of post resuscitation mild therapeutic hypothermia. ResultsSCPR+PC animals had significant improvement in left ventricular ejection fraction at 1 and 4h compared to SCPR (59±11% vs 35±7% and 55±8% vs 31±13% respectively, p<0.01). Neurological function at 24h significantly improved with SCPR+PC compared to SCPR alone (CPC: 2.7±0.4 vs 3.8±0.4 respectively, p=0.003). Neurological function significantly improved in the SCPR+PC group at 48h and the mean CPC score of that group decreased from 2.7±0.4 to 1.7±0.4 (p<0.00001). ConclusionsIschemic postconditioning with four 20-s pauses during the first 3min of SCPR improved post resuscitation cardiac function and facilitated neurological recovery after 15min of untreated cardiac arrest in pigs.