title: The effect of hypothermia "dose" on vasopressor requirements and outcome after cardiac arrest.
abstract: OBJECTIVE
  We evaluated the association between TH use and "dose" and cumulative vasopressor and inotrope requirement, survival, and neurologic outcome.
  
  
  BACKGROUND
  Therapeutic hypothermia (TH) improves outcome after cardiac arrest, but may increase vasopressor and inotrope requirements.
  
  
  METHODS
  Chart review of in- and out-of-hospital cardiac arrests between 1/1/2005 and 3/15/2010. Data included demographic information, category of post-cardiac arrest illness severity ((I) awake, (II) coma (not following commands but intact brainstem responses)+mild cardiopulmonary dysfunction (SOFA [Sequential Organ Failure Assessment] cardiac+respiratory score<4), (III) coma+moderate-severe cardiopulmonary dysfunction (SOFA cardiac+respiratory score≥4), and (IV) coma without brainstem reflexes), cumulative vasopressor index (CVI), inotrope use, survival, and neurologic outcome. The "dose" of TH (hours*temperature below threshold) was calculated using thresholds of ≤34 °C and ≤35 °C. Data were analyzed using descriptive statistics, Student's t-test, Wilcoxon test, and chi-squared analysis. Linear and logistic regression evaluated the effect of hypothermia "dose" on total CVI, survival and neurologic outcome.
  
  
  RESULTS
  Among 361 comatose patients, 233 (65%) received TH. Vasopressor administration (measured by CVI) was higher in normothermic subjects (60.2% vs. 46.4%; p=0.016). Using a 34 °C threshold, SOFA respiratory subscore and PEA arrest predicted total CVI. Using a 35 °C threshold, severity of coma, SOFA respiratory subscore, PEA arrest and use of inotropic agents in addition to vasopressors predicted total CVI. Initial motor examination predicted survival and neurologic outcome, while TH "dose" did not.
  
  
  CONCLUSIONS
  TH delivery is not associated with vasopressor requirement. TH "dose" is not associated with total CVI, survival, or good outcome. Vasopressor or inotropic requirement should not contraindicate TH use.
authors: University of Southern California, Department of Internal Medicine, USA.
authors: Nicholas
authors: N
authors: Huynh
authors: John
authors: J
authors: Kloke
authors: Chen
authors: C
authors: Gu
authors: Clifton W
authors: CW
authors: Callaway
authors: Francis X
authors: FX
authors: Guyette
authors: Kory
authors: K
authors: Gebhardt
authors: Rene
authors: R
authors: Alvarez
authors: Samuel A
authors: SA
authors: Tisherman
authors: Jon C
authors: JC
authors: Rittenberger
mesh_terms: D002316:Cardiotonic Agents / Q000008:administration & dosage*; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*
chemical_list: D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents