| Abstract: | Aim of the studyWe investigated the effects of ischemic postconditioning (IPC) with and without cardioprotective vasodilatory therapy (CVT) at the initiation of cardiopulmonary resuscitation (CPR) on cardio-cerebral function and 48-h survival.MethodsProspective randomized animal study. Following 15 min of ventricular fibrillation, 42 Yorkshire farm pigs weighing an average of 34 ± 2 kg were randomized to receive standard CPR (SCPR, n = 12), SCPR + IPC (n = 10), SCPR + IPC + CVT (n = 10), or SCPR + CVT (n = 10). IPC was delivered during the first 3 min of CPR with 4 cycles of 20 s of chest compressions followed by 20-s pauses. CVT consisted of intravenous sodium nitroprusside (2 mg) and adenosine (24 mg) during the first minute of CPR. Epinephrine was given in all groups per standard protocol. A transthoracic echocardiogram was obtained on all survivors 1 and 4 h post-ROSC. The brains were extracted after euthanasia at least 24 h later to assess ischemic injury in 7 regions. Ischemic injury was graded on a 0–4 scale with (0 = no injury to 4 ≥50% neural injury). The sum of the regional scores was reported as cerebral histological score (CHS). 48 h survival was reported.ResultsPost-resuscitation left ventricular ejection (LVEF) fraction improved in SCPR + CVT, SCPR + IPC + CVT and SCPR + IPC groups compared to SCPR (59% ± 9%, 52% ± 14%, 52% ± 14% vs. 35% ± 11%, respectively, p < 0.05). Only SCPR + IPC and SCPR + IPC + CVT, but not SCPR + CVT, had lower mean CHS compared to SCPR (5.8 ± 2.6, 2.8 ± 1.8 vs. 10 ± 2.1, respectively, p < 0.01). The 48-h survival among SCPR + IPC, SCPR + CVT, SCPR + IPC + CVT and SCPR was 6/10, 3/10, 5/10 and 1/12, respectively (Cox regression p < 0.01).ConclusionsIPC and CVT during standard CPR improved post-resuscitation LVEF but only IPC was independently neuroprotective and improved 48-h survival after 15 min of untreated cardiac arrest in pigs. |
