Abstract 281: Initial Illness Severity Not Hypothermia Treatment is Associated With Outcome After Cardiac Arrest
Background: The effect of illness severity on response to therapeutic interventions for cardiac arrest such as therapeutic hypothermia (TH) is unknown. This study examined the effects of TH on survival and functional outcome when subjects were categorized by early illness severity after cardiac arrest.
Methods: Retrospective review of data from adults treated after in-hospital or out-of-hospital cardiac arrest in a single tertiary care facility between before and after implementation of a TH program between 1/1/2005 and 12/31/2009. In addition to clinical data, initial illness severity was measured using serial organ function assessment (SOFA) scores and full outline of unresponsiveness (FOUR) scores at hospital or intensive care unit arrival. Outcomes were hospital mortality, good outcome (discharge to home or rehabilitation) and development of multiple organ failure (MOF).
Results: Complete data from 459/497 (92%) subjects identified distinct categories of illness severity using combined FOUR motor and brainstem subscales, and combined SOFA cardiovascular and respiratory subscales: I. Awake; II. Moderate coma without cardiorespiratory failure; III. Moderate coma with cardiorespiratory failure; and IV. Severe coma. Survival was independently associated with category (II: OR 0.31; 95% CI 0.17, 0.55; III: OR 0.19; 95% CI 0.1, 0.36; IV: OR 0.03; 95% CI 0.01, 0.05). Category was also associated with good outcome and development of MOF. Survival from ventricular fibrillation (VF) cardiac arrest increased after implementation of TH. However, the proportion of subjects in each category changed over time. When adjusted for category, there was no effect of TH on survival, good outcome and development of MOF. None of these outcomes improved within a category after implementation of TH.
Conclusions: Initial illness severity explains much of the variation in cardiac arrest outcome. The beneficial effects of TH need to be reassessed taking illness severity into account.
- © 2010 by American Heart Association, Inc.