Ischemic post-conditioning and vasodilator therapy during standard cardiopulmonary resuscitation to reduce cardiac and brain injury after prolonged untreated ventricular fibrillation

摘要

Aim of the study: We 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. Methods: Prospective 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. Results: Post-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). Conclusions: IPC 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.