Impact of Time-to-Compression on Out-of-Hospital Cardiac Arrest Survival Outcomes: A National Registry Study

Abstract

Objective: Guidelines recommend that extracorporeal membrane oxygenation cardio-pulmonary resuscitation (ECPR) should not be used on out-of-hospital cardiac arrests (OHCA) with time-to-compression (TTC) >10 minutes. However, no literature has validated this criteria.  We aimed to compare survival with favorable neurological outcomes and survival to discharge in OHCA patients with CPR initiated >10 minutes after a recognised collapse versus  ≤10 minutes, and to determine an alternative threshold for an exclusion criterion for ECPR therapy.

Methods: All OHCAs from 2012-2017 in Singapore were extracted from our national registry. Patients who received CPR ≤10 minutes versus >10 minutes were compared. Primary outcome was favorable cerebral performance (Glasgow-Pittsburgh Cerebral Performance Categories 1/2), and secondary outcome was survival to hospital discharge/ 30th day. To determine an alternative threshold, we plotted the adjusted probability of good neurological outcomes to TTC.

Results: 12,771 OHCAs were analyzed, of which 5,704 patients had TTC 10 minutes (aOR 0.43, 95%CI: 0.32-0.58) and good neurological outcomes was lower (aOR 0.51; 95%CI: 0.41-0.62). Other significant predictors included age (aOR 0.98, 95%CI: 0.98 - 0.99), witnessed arrest (aOR 2.39, 95%CI: 1.69-3.40), bystander AED (aOR 1.55, 95%CI: 1.12-2.26), and presence of shockable rhythm (aOR 8.76, 95%CI: 7.12-10.78). A prediction curve of adjusted probability of good neurological survival vs TTC was plotted. Taking the 1% futility of survival line and extrapolating it to the lower bound in the 95% CI gave a TTC cutoff of 12 mins (NPV 99%, sensitivity 85% and specificity 42%).

Conclusion: There is a significant difference in survival and favorable neurological outcomes when TTC was >10 minutes. However, more data-driven threshold criteria instead of an arbitrary timing should be considered for eligibility of ECPR therapy.

Note:
Funding Information: This study was funded by National Medical Research Council, Clinician Scientist Awards, Singapore (NMRC/CSA/0049/2013 and NMRC/CSA-SI/0014/2017) and Ministry of Health, Health Services Research Grant, Singapore (HSRG/0021/2012).

Conflict of Interests: Prof Marcus Ong reports grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices. MEH Ong has a licensing agreement with ZOLL Medical Corporation and patent filed (Application no: 13/047,348) for a “Method of predicting acute cardiopulmonary events and survivability of a patient.” He is also the co-founder and scientific advisor of TIIM Healthcare, a commercial entity which develops real-time prediction and risk stratification solutions for triage. All other authors have no conflict of interest to disclose.

Ethical Approval: This study has been approved by the Singhealth Centralised IRB: 2018/2937.

Keywords: cardiopulmonary resuscitation, out-of-hospital cardiac arrest, Time-to-compression, neurological outcomes, survival outcomes