Abstract Body: Abstract

Background
Chest compressions are a cornerstone of cardiopulmonary resuscitation (CPR), and evidence shows that fewer interruptions and higher chest compression fractions improve outcomes in cardiac arrest. Interruptions in chest compression are important in patients with shockable rhythms to assess the need for defibrillation; however, in pulseless electrical activity (PEA) or asystole, a pause in chest compressions every 2 minutes may be detrimental, as it decreases chest compression fraction and reduces myocardial, cerebral, and systemic perfusion.

Hypothesis
We hypothesize that patients with non-shockable rhythms on whom chest compression intervals were greater than 2 minutes have better odds of achieving return of spontaneous circulation (ROSC).

Objective
Our primary objective is to determine if longer chest compression intervals are associated with improved subsequent ROSC in patients with initial PEA or asystole rhythms.

Methods
We conducted a retrospective cohort study of video-recorded adult atraumatic cardiac arrest resuscitations in a quaternary care Emergency Department from 1/30/2018 to 2/20/2024. We only examined patients in PEA or asystole and determined the duration of all chest compression intervals for each patient. We grouped the chest compression interval durations into 3 groups (<1min 45sec, 1min 45sec to 2 min 14sec, ≥2min 15 sec) and determined the odds of subsequent ROSC for each chest compression interval duration. We assessed the association between chest compression interval duration and ROSC episodes using a logistic regression model.




Results
Out of 326 video-reviewed patients, 235 patients had an initial rhythm of PEA or asystole of which 44 (18.7%) survived to admission and 9 (3.8%) to hospital discharge. The 235 patients yielded 1724 chest compression intervals and 151 ROSC episodes. The ROSC rate for the chest compression intervals <1:45sec was 7.3% (49 out of 673) versus 8.1% (51 out of 632) for intervals 1:45 to 2:14 versus 12.2% (51 out of 419) for intervals ≥2 min 15sec. In a logistic regression model, using the 1min 45 sec to 2min 14 sec interval as the reference group, the <1min 45sec group had 10% lower odds of ROSC (OR: 0.90; 95% CI: 0.60, 1.35) and the ≥2min 15 sec group had 58% higher odds of ROSC (OR: 1.58; 95% CI: 1.05, 2.38).

Conclusion
In cardiac arrest patients presenting with non-shockable rhythms, chest compression intervals ≥2 min15sec are associated with higher odds of achieving ROSC.