Sustained Return of Spontaneous Circulation Following Out-of-Hospital Cardiac Arrest; Developing a Predictive Model Based on Multivariate Analysis.

Introduction: Identifying the predictive factors of sustained return of spontaneous circulation (ROSC) following out-of-hospital cardiac arrest (OHCA) will be helpful in management of these patients. This study aimed to develop a predictive model in this regard.

Methods: In a retrospective observational study, data of adult patients with OHCA, were collected from Vajira emergency medical services patient care report. Multiple logistic regression analysis with a regression coefficient was used to develop a predictive score for a sustained ROSC at the scene. Area under the receiver operating characteristic (ROC) curve (AUC) was used to validate the accuracy of the predictive score for a sustained ROSC.

Results: Independent factors associated with a sustained ROSC included cardiopulmonary resuscitation (CPR) duration < 30 min (adjusted odds ratio (AOR)= 5.05, 95% confidence interval (CI): 3.34-7.65; p < 0.001); advanced airway management with an endotracheal tube (AOR= 3.06, 95% CI: 1.77-5.31; p < 0.001); advanced airway management with laryngeal mask airway (AOR= 3.42, 95% CI: 1.02-11.46; p = 0.046); defibrillation (AOR = 2.05, 95% CI: 1.31-3.2; p = 0.002); Capillary blood glucose (CBG) level < 150 mg% (AOR= 1.95, 95% CI: 1.05-3.65; p = 0.035); CBG at least 150 mg% (AOR= 2.87, 95% CI: 1.56-5.29; p = 0.001); pupil reflex (AOR = 2.96, 95% CI: 1.1-7.96; p = 0.032); and response time at most 8 min (AOR= 1.66, 95% CI: 1.07-2.57; p = 0.023). These were developed into the pupil reflex, response time, advanced airway management, defibrillation, CBG, and CPR duration (PRAD-CCPR) score. The most accurate cutoff point of score using Youden's index was ≥ 6 with AUC of 0.759 (95% CI: 0.715-0.802; p < 0.001), sensitivity of 62.0% (95% CI: 51.2-71.9%), specificity of 75.7% (95% CI: 69.4-81.2%), positive predictive value of 51.8% (95% CI: 40.9-62.3%), and negative predictive value of 79.5% (95% CI: 73.5-84.6%).

Conclusion: An optimal PRAD-CCPR score of ≥ 6 provides an acceptable accuracy of 0.759 with sensitivity of 62.0% and specificity of 75.7% in prediction of sustained ROSC following OHCA. This predictive score might help CPR commanders to prognosticate the outcome of patients with OHCA at the scene.