M. T. Cain1, S. Greenberg2, P. Pearson1 1Medical College Of Wisconsin,Division Of Cardiothoracic Surgery/ Department Of Surgery,Milwaukee, WI, USA 2University Of Chicago,Department Of Anesthesiology Critical Care,Chicago, IL, USA
Introduction:
Induction of systemic hypothermia is a common technique during cardiac surgery to aid in tolerance of low flow states associated with cardiopulmonary bypass (CPB). Reduced regional blood flow, hemodilution from the CPB circuit, and cerebral hyperthermia during the rewarming phase of CPB all place patients at risk for neurological injury or dysfunction. A simple, practical, and safe intraoperative tool for selective cerebral hypothermia could provide the neuroprotective advantages of systemic cooling without the adverse effects of hyperthermic rebound. Here we present results on the feasibility of utilizing an external transcranial cerebral cooling device (WElkins Portable Temperature Management System, Welkins,LLC Downers Grove, IL), in conjunction with conventional intraoperative monitors, for cerebral cooling during cardiac surgery requiring CPB.
Methods:
Prospective core and tympanic patient temperature data was collected for all subjects. Patients were fitted with the cooling device after placement of traditional monitors and intraoperative positioning. Cooling was initiated and temperatures were monitored at 20 minute intervals throughout each procedure, and during the first 6 hours of immediate postoperative intensive care unit (ICU) recovery. Systemic cooling procedures via CPB circuit was not adjusted due to device implementation. Outcome variables included device failure rate, cerebral temperature reduction by tympanic probe, resource burden for implementation, device disruption of standard patient monitoring devices, and adverse device events including alopecia, pressure ulceration, or skin damage.
Results:
A total of 18 patients underwent device placement. Complete data was obtained on 16 patients. There were no device failures, however there were two early device discontinuations related to persistent postoperative hypothermia (11.1%). Mean tympanic temperature reduction was 1.0°C intraoperatively (0.5-1.6°C) and 1.2°C during ICU recovery (0.5-1.9°C) relative to core temperature. No harms or interference with standard patient monitoring devices were noted, and device implementation required a mean technician time of 245 minutes intraoperative and 261 minutes postoperatively.
Conclusion:
External transcranial selective cerebral cooling is a feasible technique that can be performed in conjunction with standard patient monitoring devices without evidence of local skin or hair damage, or interference with patient care in this early data series. Expanded use of this device is required to further characterize its benefit on neurological outcomes after cardiac surgery.