Abstract 103: Rewarming Speed Affects Cardiopulmonary and Neurological Functions After Deep Hypothermic Cardiac Arrest

Introduction: The optimal rewarming rate from accidental or induced deep hypothermia is still unknown. Fast extracorporeal rewarming by extracorporeal circulation has been associated with cardiac dysfunction, pulmonary edema and poor neurologic outcome. Hypothesis: This study investigates whether the speed of rewarming after deep hypothermic cardiac arrest has neurological and cardiopulmonary effects. Methods: Thirty male Sprague-Dawley adult rats (450-550g) were rapidly cooled (ice packs) until 15°C core body temperature. Deep hypothermic cardiac arrest was maintained for 60 min. Thereafter rats were randomised to receive slow (90 minutes) or fast (30 minutes) rewarming by cardiopulmonary bypass to a target temperature of 35°C. After 90 minutes of reperfusion all animals underwent hemodynamic assessment by biventricular pressure-volume analysis, brain MRI and heart, lungs and brain were collected. Results: Slow rewarming preserved cardiac systolic and diastolic functions, ventricular arterial coupling and endothelium dependent relaxation. Lung edema was attenuated after slow rewarming. Cardimyocytes pro-survival kinases ERK and Akt activation were significantly higher in the slow rewarming group. MRI demonstrated enhancement of cerebral blood flow and reduction of cerebral edema after slow rewarming. Neurologic inflammatory response measured by IL-6, ICAM-1, CCL5 and TNF-α expression was significantly decreased in the slow rewarming group. Oxidative stress assessed by malondialdehyde was significantly reduced after slow rewarming. Conclusion: Slow rewarming by extracorporeal circulation after deep hypothermic cardiac arrest might improve systolic and diastolic function, preserve ventricular-arterial coupling, attenuate cerebral perfusion impairment and reduce neuronal damage.

The Role of Deep Hypothermic Cardiac Arrest in the Surgical Treatment of Complex Intracranial Aneurysms

Giant and complex intracranial aneurysms can be formidable lesions to tackle from a surgical standpoint. Their treatment has witnessed an enormous improvement in recent decades with the development of several technical refinements, both surgical and endovascular. By combining optimal cerebral protection with extended periods of circulatory control, deep hypothermic cardiac arrest (DHCA) is a useful adjunct for appropriately dealing with very select cases. In this article we discuss the rationale behind the use of DHCA and review the results of the most relevant series recently published. DHCA remains an important though exceptional way of surgically treating giant and complex intracranial aneurysms.