Abstract 31: The Effect of Hypothermia “Dose” on Vasopressor Requirements and Outcome After Cardiac Arrest
Introduction Therapeutic hypothermia (TH) improves outcome after cardiac arrest, but may result in increased vasopressor requirements. We evaluated the association between TH use and cumulative vasopressor and inotrope requirement. The effect of TH “dose” on cumulative vasopressor index, survival and neurologic outcome was also explored.
Methods Review of chart data from subjects treated after resuscitation from out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrests between 1/1/2005 and 3/15/2010. Data included demographic information, category of post-cardiac arrest illness severity ( (1) awake, (2) coma (not following commands but intact brainstem responses) + mild cardiopulmonary dysfunction (SOFA [Sequential Organ Failure Assessment] cardiac + respiratory score <4), (3) coma + moderate-severe cardiopulmonary dysfunction (SOFA cardiac + respiratory score >=4), and (4) coma without brainstem reflexes), cumulative vasopressor index (CVI) over first 72 hours, inotrope use, and outcomes (survival, good functional outcome). The “dose” of TH (hours*temperature below cut point) was calculated using cut points of ≤34°C and ≤35°C. Data were analyzed using descriptive statistics, Student's-t test, Wilcoxon test, and chi-squared analysis, as appropriate. The effect of hypothermia dose on total CVI, survival and neurologic outcome was assessed using regression.
Results Among a total of 558 patients, 250 (45%) received induced hypothermia. The rate of administration of vasopressors (measured by CVI) or inotropes was not different between TH and normothermia subjects. Using either a 34°C or 35°C cutoff, only category 4 illness severity or use of inotropic agents in addition to vasopressors predicted total CVI. Survival was not predicted by TH “dose” but was predicted by category 4 illness severity. Neurologic outcome was predicted by category 4 illness severity and OHCA. CVI had no independent effect on survival or neurologic outcome.
Conclusions TH delivery is not associated with increased vasopressor requirement. The “dose” of hypothermia is not associated with total CVI, survival, or good outcome. Vasopressor or inotropic requirement appears to be unrelated to TH use.
- © 2011 by American Heart Association, Inc.