Abstract 18120: The Relationship Between Estimated Total Ischemic Time and Hospital Survival in Patients Suffering From Out of Hospital Cardiac Arrest

Abstract

Introduction: The incidence of out of hospital cardiac arrest (OHCA) in the U.S. is approximately 400,000 patients per year. Despite quality improvement efforts, overall survival after cardiac arrest remains poor, suggesting that there are other factors at play. One such variable is total ischemic time. This analysis was performed to determine the role of total ischemic time in hospital survival after OHCA. Methods: The OHCA records were queried from the cardiac arrest registry maintained by Houston Fire department from 2007-2012.Association between outcome and predictor variables was assessed using logistic regression. The outcome variable is defined as survival and discharge from the hospital. Our predictor variable of interest was Estimated Total Ischemic Time, which was calculated as the difference between time of Return of Spontaneous Circulation (ROSC) and Fire Rescue Dispatch time. The Hosmer-Lemeshow Goodness of Fit test grouped by ten showed that the null (the model) should not be rejected (p = 0.8678). The final model includes Estimated Total Ischemic Time, age divided into categories by decade, presence of a shockable rhythm, and presence of a witness to the cardiac arrest. Results: The database consisted of 9,074 OHCA cases, of which 446 were included in the final analysis. According to our model, the data suggests there is a decrease in probability of survival as estimated total ischemic time increases. The odds of survival and discharge from the hospital of an OHCA patient with an estimated total ischemic time of 2 minutes is 0.956 (95%CI 0.936 - 0.977) times the odds of a patient whose estimated total ischemic time was 1 minute. Conclusion: Estimated Total Ischemic Time is a significant contributor to the probability of survival, however it is not the only one. This model exemplifies just one example of the importance of adjusting for both prehospital and hospital care in clinical decision-making and healthcare quality improvement.