Cardiopulmonary instability score and in-hospital mortality in critically ill patients with cardiovascular disease: a retrospective eICU cohort study.

Abstract

To explore the association between a four-item cardiopulmonary instability (CPI) score assessed during the first 24 hours of intensive care unit (ICU) admission and in-hospital mortality among critically ill adults with cardiovascular disease. Retrospective multicentre cohort study. The eICU Collaborative Research Database, comprising ICU admissions from hospitals in the USA during 2014-2015. Eligible ICU stays among adults aged ≥18 years with cardiovascular disease and known hospital outcome status. The ICU stay was the unit of analysis. The first 24-hour CPI score assigned one point each for hypotension, hypoxaemia, tachycardia and mechanical ventilation, yielding a total score ranging from 0 to 4. The primary outcome was in-hospital mortality. Secondary outcomes were ICU mortality and prolonged ICU and hospital stays. The cohort included 61 273 eligible ICU stays contributed by 49 991 patients across 206 hospitals; 8238 stays (13.4%) resulted in in-hospital death. All four CPI components were available for 55 601 stays (90.7%). Mortality increased from 1.4% with CPI 0 to 4.6%, 11.6% and 28.0% with CPI 1, 2 and 3-4, respectively. In the adjusted analysis, CPI≥2 was associated with in-hospital mortality (OR 4.45, 95% CI 4.06 to 4.89; relative risk 3.64, 95% CI 3.35 to 3.97). CPI alone had moderate apparent discrimination (area under the receiver operating characteristic curve 0.732, 95% CI 0.726 to 0.738). At the CPI≥2 threshold, sensitivity was 90.4%, specificity 39.4%, positive predictive value 18.8% and negative predictive value 96.3%. Findings were consistent in analyses excluding mechanical ventilation, restricting stays to >24 hours and accounting for repeated stays. CPI ≥2 was also associated with secondary outcomes. In this retrospective multicentre eICU cohort, higher first-day CPI scores were associated with progressively greater in-hospital mortality, while CPI≥2 was associated with ICU mortality and prolonged ICU and hospital stays. CPI provides a simple descriptive summary of first-day CPI, but its moderate apparent discrimination and low positive predictive value do not support stand-alone use for individual prognostication or treatment decisions.