Abstract 45: Non-Selective Cyclooxygenase Inhibition Prior To Periodic Acceleration (pGz) Cardiopulmonary Resuscitation (CPR) in a Porcine Model of Ventricular Fibrillation
Background: Whole body periodic acceleration (pGz) along the spinal axis is a novel method of cardiopulmonary resuscitation (CPR). Oscillatory motion of the supine body in a horizontal fashion provides ventilation and blood flow to vital organs during cardiac arrest. We previously showed that pGz-CPR affords better post resuscitation myocardial function, better overall survival and neurological outcomes in pigs compared to conventional chest compression CPR. We have also shown that pGz via pulsatile shear stress induces endothelial derived prostaglandins. The latter has been shown to be cardio protective. Indomethacin a non selective cyclooxygenases inhibitor was used to investigate the role of prostaglandins during pGz-CPR on acute outcomes of survival, cardio protection and regional blood flows (RBF).
Methods: Two groups of pigs (25–36 kg) were studied. Prior to electrical induction of ventricular fibrillation (VF) animals received equal volumes of either saline placebo Control (CONT) (n = 9) or Indomethacin (INDO), (n = 8), (2 mg/kg). After 3 min of unsupported VF, both groups received 15 min of pGz-CPR followed by a single dose of Vasopressin, bicarbonate and no more then 5 defibrillation attempts.
Results: Return of circulation (ROSC) to 3 hrs occurred in (78%) in CONT and (63%) in INDO pretreated animals. There was no statistically significant difference in hemodynamics between groups at baseline or during the protocol. INDO caused a 19% decrease in RBF to brain after infusion. At 2 hrs of ROSC, RBF to brain and heart in CONT were increased 46% and 16% of baseline respectively. In contrast INDO treated animals only had a 9% and 4% increase in RBF above baseline. The wall motion index (WMSI) was most impaired for INDO group. At 30 and 120 min after ROSC, WMSI for CONT was 1.6(0.45) and 1.8(0.25) vs. INDO of 2.6(0.4) and 2.5(0.4) respectively. There was a 4 fold difference in the troponin 1 concentration; CONT 35 (8) vs. INDO 185 (71)ng/ml.
Conclusions: Non specific acute inhibition of COX with indomethacin is deleterious during pGz-CPR. These data suggest that in part prostaglandins are involved in the cardioprotection induced by pGz during CPR.