Abstract 167: Selective Head Cooling Initiated During CPR and Continued Following Return of Spontaneous Circulation Improves Coronary Perfusion Pressure and Myocardial Tissue Perfusion After Cardiac Arrest
Background: We have reported that head cooling improved post resuscitation myocardial function, while systemic cooling by cold saline intravenous infusion (CSI) did not. Nevertheless, CSI is now accepted as a simple method of inducing hypothermia. We explored the effects of head cooling and CSI on myocardial perfusion. We hypothesized that head cooling would improve myocardial perfusion.
Methods: Ventricular fibrillation was induced in 15 pigs, 38 ± 1 kg, and untreated for 10 mins. CPR, including mechanical chest compression and ventilation was then performed for 5 mins prior to defibrillation. Coincident with the start of CPR, animals were randomized into: 1. head cooling with the RhinoChill device; 2. systemic cooling by CSI (30 mL/kg 4°C, in 30 mins) followed by surface cooling; or 3. control. Aortic, right atrial and coronary perfusion pressures (CPP) were continuously measured, together with rectal and brain temperatures. Myocardial perfusion was assessed using colored microspheres (diameter 10 ± 0.2 μm) technique.
Results: All the animals with the exception of one control were successfully resuscitated. Head cooling rapidly decreased the brain temperature (p < 0.01). CSI significantly decreased both brain and rectal temperatures (Table). Animals subjected to head cooling showed significantly higher CPP following resuscitation (Table). These increases in CPP were accompanied by improvements in myocardial perfusion (p < 0.01, Fig). Those beneficial effects were not observed during CSI.
Conclusions: Head cooling, but not systemic cooling, initiated during CPR and continued following resuscitation, improved CPP and myocardial perfusion after cardiac arrest.
- © 2010 by American Heart Association, Inc.