Active compression decompression (ACD) cardiopulmonary resuscitation (CPR) plus augmentation of negative intrathoracic pressure with an impedance threshold device (ITD) has been shown to increase cerebral perfusion compared with standard CPR (S-CPR) by a) increasing forward brain blood flow, and b) by reducing resistance to brain flow by lowering intracranial pressure. The ResQTrial compared ACD+ITD (n= 840 patients) versus S-CPR (n=813) after out-ofhospital, nontraumatic cardiac arrest of presumed cardiac etiology. ACD+ITD improved survival to hospital discharge with favorable neurological function by 53% [odds ratio (OR) 1.58, 95% confidence interval (CI) 1.07-2.36; p=0. 019]. Due to differences in local practice, many of the patients in this trial were not treated with post-resuscitation therapeutic hypothermia (TH), a neuro-protective therapy. The objective of this current analysis was to determine whether ACD+ITD is neuro-protective independent of TH.
Post-hoc analysis of ResQTrial data compared a) the rate of hospital discharge with favorable neurological function, [modified Rankin scale (MRS) <= 3], and b) 90-day survival with favorable neurological function [cerebral performance score (CPC) of <3] for all patients not treated with TH.
Without use of TH, ACD+ITD was independently associated with a nearly two-fold increase in the number of survivors with favorable neurological function at the time of hospital discharge [ACD+ITD (40/711) versus S-CPR (20/669), (p= 0.017, OR= 1.93, CI = 1.09, 3.53], and 90 days after the cardiac arrest [ACD+ITD (35/706) versus S-CPR (19/664), p= 0.052, OR= 1.77 , CI = 0.97, 3.31].
In the absence of treatment with TH after cardiac arrest, survival rates with favorable neurological function at hospital discharge and 90 days after cardiac arrest were nearly twice as high with ACD+ITD versus S-CPR. These findings support the hypothesis that use of ACD+ITD is neuro-protective, independent of in-hospital TH.