Abstract 2657: Total Liquid Ventilation with Chilled Perfluorocarbons Rapidly Achieves Moderate Hypothermia and Facilitates Cardiopulmonary Resuscitation in a Swine Model
Background: Previous swine experiments in our laboratory have shown that induced hypothermia during ventricular fibrillation (VF) improves defibrillation success and resuscitation outcomes. Static endotracheal instillation of chilled perfluorocarbons (PFC) during VF achieves moderate hypothermia (33°C) more rapidly than external ice application. However, this method of chilling still requires 10 minutes to achieve 33°C. Our objective was to determine if total liquid ventilation (TLV) using chilled preoxygenated PFC would more rapidly achieve cardio-pulmonary hypothermia.
Methods: Thirty-three female swine were divided into 3 groups: Normothermic (N) (n=11), Hypothermic (H) (n=11) and Control (C) (n=11). VF was induced electrically via RV stimulation. H swine were immediately ventilated via TLV with pre-oxygenated chilled PFC (-15°C); N swine were immediately ventilated via TLV with pre-oxygenated warmed PFC (33°C). C swine received no intervention during the VF arrest. All swine underwent VF arrest for 11 minutes, then defibrillation, ventilation and closed chest massage until resumption of spontaneous circulation (ROSC) or a minimum of 11 minutes.
Results: In the H group, pulmonary artery (PA) temperature fell from baseline 36.9±0.1°C to 33.8±0.4°C at 4 minutes of VF arrest and to 31.9±0.4°C at 10 minutes of VF arrest (p<0.01). In the N and C groups baseline PA temperatures were 37.6±0.4°C and 37.5±0.3°C, and did not change during VF. Compared to our previous static endotracheal instillation of chilled PFC experiments, hypothermia was achieved faster using TLV; at 4 minutes VF, TLV temperature was 33.8±0.4°C vs. static instillation temperature 34.9±0.2°C (p=0.01); at 6 minutes VF, TLV temperature was 32.9 ±0.4°C vs. static instillation 34.5±0.2°C (p<0.01). Nine of 11 H swine achieved ROSC for 1 hour when compared to 3 of 11 C swine (p=0.03); eight of 11 N swine achieved ROSC vs. C swine (p=0.09). Defibrillation shocks per animal were 5.3±1.9 H, 3.0±0.6 N and 7.5±1.5 C (p=0.08).
Conclusion: Targeted cardiopulmonary intra-arrest moderate hypothermia was achieved very rapidly via total liquid ventilation with chilled PFC. This facilitated cardiopulmonary resuscitation in a female swine model.