Abstract 321: Reperfusion Target Temperature Study for Resuscitation and Long-Term Survival from Prolonged Ventricular Fibrillation Cardiac Arrest in Rats
BACKGROUND: Emergency cardiopulmonary bypass (ECPB) allows for target temperature reperfusion and resuscitation from prolonged cardiac arrest, although the ideal reperfusion temperature is not known to date. We tested three reperfusion profiles in a rat model of prolonged ventricular fibrillation (VF) cardiac arrest (CA) with ECPB resuscitation.
METHODS: Twenty-four adult male Sprague-Dawley rats (470 g) were anaesthetized, ventilated and instrumented before being subjected to VF CA for 10 minutes. Then, rats were randomize to to normothermic (NT, 37±0.5°C), mild hypothermic (MH, 33±0.5°C) or deep hypothermic (DH, 27±0.5°C) reperfusion. Rats were put on EPCB and temperature controlled at target. After 15 minutes of ECPB resuscitation, 25 minutes after initiation of CA, rats were defibrillated, weaned from ECPB, and returned to their cages. Temperature was controlled at 33°C (MH and DH) or 37°C (NT) for twelve hours. Outcome parameters included return of spontaneous circulation (ROSC), survival to one month with overall performance category (OPC) and vital neuron count in CA1.
RESULTS: See table 1. ROSC was achieved in all animals of MH, and in 6 of 8 animals in DH and NT groups. Four of the NT and 3 of the DH animals did not survive the first night (OPC 5), the remaining animals recovered to OPC 2. In the MH group, all animals survived to one week. However, two animals (OPC 3) had to be terminated due to loss of weight >20%. The remaining animals of the MH group recovered to OPC 1 or 2 and had a vital neuron count equal to comparatively aged naïve animals at final examination.
CONCLUSION: A mild hypothermic reperfusion strategy appears most superior to normothermic or deep hypothermic ECPB resuscitation, although owing to the small group size, statistically significant difference in OPC could only be proven for MH vs. NT. MH ECPB resuscitation results in 100% viable hippocampal neurons after one month.
- Ventricular fibrillation
- Cardiac arrest
- Cardiopulmonary resuscitation
- Return of spontaneous circulation (ROSC)
Author Disclosures: I.A. Magnet: None. F. Ettl: None. A. Schober: None. A. Warenits: None. C. Testori: None. D. Grassmann: None. M. Wagner: None. C. Schriefl: None. C. Clodi: None. U. Teubenbacher: None. S. Högler: None. W. Weihs: None. F. Sterz: None. A. Janata: Research Grant; Modest; Austrian Science Foundation P24824.
- © 2014 by American Heart Association, Inc.