Abstract 280: Cerebral Blood Flow and Oxygenation During CPR in Swine

Abstract

Introduction: Near-infrared spectroscopy (NIRS) has been used during cardiac arrest (CA) to non-invasively measure cerebral oxygenation. Studies have suggested that survival and neurological outcomes can be predicted using cerebral oxygenation, however, the physiology underlying cerebral oxygenation during CA is poorly understood. This exploratory study examined the behavior of cerebral blood flow and oxygenation in response to standard CPR (SCPR) and CPR with Active decompression and lift (ACD) and an impedance threshold device (ITD). Methods: Ventricular fibrillation was electrically induced in eight domestic swine. Following six minutes of untreated VF, SCPR (100 cpm at 20% anterior-posterior distance) was performed for six minutes. ACD+ITD was performed for an additional six minutes at the same rate and depth as SCPR, but with an additional 20% anterior-posterior distance of active lift. Cerebral blood flow was measured via microspheres and cerebral oxygenation was measured using NIRS. Animals were classified as responders if cerebral oxygenation increased within two minutes of initiating SCPR. Cerebral oxygenation did not change or declined during SCPR in non-responders. Results: Six out of eight animals were classified as responders. Cerebral blood flow and oxygenation increased with ACD+ITD compared to SCPR in responders but failed to increase for non-responders. Cerebral blood flow and oxygenation were lower during baseline (BL) in non-responders (Figure). Conclusions: ACD+ITD appears to improve cerebral blood flow and oxygenation. Changes in cerebral oxygenation during CA appear to be associated with measured changes in cerebral blood flow. NIRS may be clinically useful in estimating oxygenation and blood flow during low blood flow states and monitoring physiological responses to different interventions. Failure of improvement in NIRS during CPR may predict poor outcomes and/or the need for additional interventions guided by NIRS.