Substance abuse as predictor of in-hospital mortality in patients with cardiac arrest

Abstract

Introduction: Initial cardiac rhythm (ICR) is associated with mortality in cardiac arrest (CA) patients with return of spontaneous circulation (ROSC) [1]. However, knowledge regarding a possible association between substance abuse and mortality is limited. Objectives: (1)To determine whether substance abuse is associated with in-hospital mortality in patients with CA admitted to ICÙs (intensive care units), and (2) to study the association between substance abuse and ICR. Methods: CA patients with ROSC-admitted to the ICÙs at Oslo University Hospital Ullevål from Feb.3, 2014 to Feb.2,2015-were included as part of a multicenter prospective observational study of ICU patients in Oslo (n = 900). Informed consent was given by the next of kin, and if possible, later by the patient. Illicit drug/alcohol abuse (acute or chronic) was assessed via standard questionnaires, biochemical analysis (drug screen) and medical records. The patients were divided into groups based on ICR: 1) non-shockable rhythm (asystole/pulseless electric activity) and 2) shockable rhythm (VF/VT). Chi-square test was used for statistical analysis, p value < 0.05 was considered statistically significant. Results: 145 patients (116 (80 %) males)) were included, reflecting a participation rate of 95 %. 72(50 %) had non-shockable rhythm, and 73(50 %) had shockable rhythm (mean age 62 vs 63). There were significantly more females in the non-shockable group (21vs.8, p < 0.01), corresponding with earlier studies. Acute drug intoxication was considered triggering cause in 7 patients (5 %), all males (mean age 43vs 64). Main agents were: Opioids (4/7), alcohol (2/7,both with blood levels > 4.2 g/L (92 mmol/L)) and benzodiazepines (1/7). All these patients were in the non-shockable group. However, the sample size was too small for further analysis to be pursued. Among the 31 (21 %) classified with chronic substance abuse (27(87 %)males, mean age 59 vs. 64) alcohol was the predominant substance (75 %), followed by illicit substances (21 %) and prescription drugs (5 %). The proportion of patients with chronic abuse was significantly higher among patients with non-shockable rhythm (32 % vs 13 % p = 0.005). In-hospital mortality was significantly higher among patients with non-shockable rhythm (83 % vs 42 %, p < 0.001). Chronic abuse, however, was not significantly associated with in-hospital mortality (p = 0.43). Conclusions: Chronic substance abuse is common among patients with CA and is significantly associated with non-shockable ICR. As expected, in-hospitality mortality was significantly higher in the non-shockable group. Although chronic abuse was associated with non-shockable initial rhythm, it was not associated with in-hospital mortality. [Table Presented].