(1393) Amplifying Functional Survival for Patients Presenting With Unwitnessed Cardiac Arrests and Asystole

Introduction: Each day, ~400 U.S. citizens have an unwitnessed out-of-hospital arrest (OHCA) presenting with asystole. The respective likelihood of resuscitation and eventual survival with good neurological function (SURV-GNF) remains bleak. This study was conducted to evaluate for any enhanced ability to achieve SURV-GNF by rapidly applying non-invasive CPR adjuncts known to boost cerebral circulation through the lowering of ICP and augmenting venous return to the heart (impedance threshold device [ITD], active compression-decompression {ACD] and automated gradual head-thorax upward positioning [AHUP]).

Methods: Using prospectively-collected data from a national registry of non-traumatic OHCA patients receiving AHUP-CPR, those with unwitnessed arrests and asystole presentations were assessed for SURV-GNF and then directly compared to the conventional CPR (C-CPR) counterparts from published NIH clinical trials that used high performance EMS systems, including those requiring documented recordings of quality C-CPR performance. Outcomes also were compared to concurrent national CARES registry data. All patients received standard EMS interventions, but AHUP-CPR patients also quickly received 2 min of circulation priming with ITD/ACD-CPR followed by head/thorax elevation (24 cm at occiput) over 2 mins. All well-known outcome-related variables were compared (age, sex, EMS-witnessed, bystander-witnessed, bystander-CPR, elapsed-time from 9-1-1 call receipt to EMS-initiated CPR [T-CPR]).

Results: Baseline characteristics were all comparable across groups including median T-CPR (uniformly ~8 min); median AHUP time (T-AHUP) was 11 min. Evaluating all unwitnessed/asystole patients, including outliers with delayed-response, unadjusted SURV-GNF for AHUP-CPR was 1.5% (n=480) vs 0.3% for C-CPR (n=766) in the NIH trial groups (p=0.015) and 0.6% (n=101,421) for the CARES registry patients (p=0.0097).

Conclusions: These findings provide evidence that the AHUP-CPR strategy is capable of increasing likelihoods of SURV-GNF for OHCA patients for whom resuscitation efforts have traditionally been considered relatively futile. Though the % surviving remains relatively low, the sheer magnitude of daily cases encountered indicates the potential for annually restoring many hundreds of functional lives in the U.S. alone.