Abstract 198: Finding The Sweet Spot Of Chest Compression Rate And Fraction For Improved OHCA 72-hour Survival

Abstract

Introduction: Cardiac arrest resuscitation guidelines recommend optimization of both chest compression rate (CCR) and fraction (CCF). Simultaneous management of CCR and CCF is challenging. The interaction between CCR and CCF is unknown. Our objective was to evaluate the influence of CCR, CCF and their interactions upon OHCA 72-hour survival. Methods: Retrospective analysis of adult OHCA in the Pragmatic Airway Resuscitation Trial (PART). We determined CCF and CCR from automated signal analysis of available CPR process files. CCF categories were <80%, 80-89.99%, and ≥90%. CCR categories were <100, 100-129.99, and ≥130 per minute. The primary outcome was 72-hour survival. We evaluated the multiplicative interaction between CCR and CCF using a) heat maps, and b) linear mixed modeling with EMS agency as a random effect, adjusted for Utstein variables. Results: Of 3,004 enrolled patients, we included 1,606 with available CPR process data. Mean CCR and CCF were 114 compressions/min (SD 9.96) and 88% (SD 0.08). On linear mixed modeling, CCR of <100 (OR 1.55, 95% CI 0.98, 2.44) and ≥130 (OR 1.29, 95% CI 0.86-1.95), referent 100-129.99, was not associated with improved 72-hour survival. A CCF of <80% (OR 1.55, 95% CI 0.98, 2.44) and ≥90% (OR 1.29, 95% CI 0.86-1.95), referent 120-129.99, was also not associated with improved 72-hour survival. Further, the interaction of CCR and CCF was not associated with improved 72-hour survival (p=0.22). Heat map analysis indicated 72-hour survival was lowest when both CCF <80% and CCR <100 per minute, and highest when CCF >90% and CCR <130 per minute (Figure). Conclusion: The interaction between CCR and CCF may influence 72-hour survival. Rescuers must seek to optimize both CCR and CCF during resuscitation attempts. Research in cardiac arrest outcomes should consider this relationship and plan to have sufficient power to explore varying CCR and CCF values when examining OHCA survival.