Abstract 02: Association Between Hospital Volume of Cardiopulmonary Resuscitation for In-Hospital Cardiac Arrest and Survival to Hospital Discharge

Background: Prior studies have shown that hospital case volume is not associated with survival in patients with out-of-hospital cardiac arrest (OHCA). However, how case volume impact on survival for in-hospital cardiac arrest (IHCA) is unknown Methods: We queried the National Inpatient Sample (NIS) in the U.S. 2005-2011 to identify cases in which in-hospital CPR was performed for IHCA. Years > 2011 were excluded due to redesign of NIS that precludes case volume calculation. Restricted cubic spine was used to evaluate the association between hospital annual CPR volume and survival to hospital discharge. Further analysis was conducted with case volume in quartiles. Results: Across more than 1000 hospitals in NIS, we identified 137,466 cases (mean age 67, 45% female) of IHCA for which CPR was performed over the study period. Median [Q1, Q3] case volume was 68 [34, 100]. Compared to those in the 1 st quartile (q1) of case volume, hospitals in the 4 th quartile (q4) tends to have younger patients (mean=66 vs 68 yrs), higher comorbidities (median Elixhauser score=4 vs 3), large bed size (89 vs 37%), and in low income areas (37 vs 32%). After adjustment for patient and hospital factors, higher hospital case volume was inversely associated with lower rates of survival (Fig1). Risk-adjusted rates of survival from q1 through q4 were: 28.1%, 25.5%, 25.4% and 23.7%. We arrived at similar results when analysis was stratified by age, gender and hospital bed size (not shown) except that the difference across quartiles was more pronounced among small bed size hospitals (survival rate=27.4% in q1 vs 8.1% in q4). However, among those who survived to hospital discharge, nonroutine home discharge was higher among patients in q1 (73.9%) vs q4 (69.6%) Conclusion: Unlike OHCA, hospital case volume is inversely associated with survival to hospital discharge in patients undergoing CPR for IHCA. Hence, quality measures to reduce the incidence of CPR/IHCA have the potential to reduce in-hospital mortality