title: Therapeutic hypothermia is associated with a decrease in urine output in acute stroke patients.
abstract: OBJECTIVE
  It is unclear what effect therapeutic hypothermia may have on renal function, because its effect has so far been primarily evaluated in settings in which there may be possible confounding perturbations in cardiovascular and renal physiology, such deep intraoperative hypothermia, general anesthesia, and post-cardiac arrest. We sought to determine if therapeutic hypothermia affects renal function in awake patients with normal renal function who were enrolled into a clinical trial of hypothermia plus intravenous thrombolysis for acute ischemic stroke.
  
  
  METHODS
  Eleven patients with normal renal function were cooled to 33°C for 24 h using an endovascular catheter, and then re-warmed over 12 h to 36.5°C, while hourly temperature, blood pressure, and fluid status data was recorded. Blood samples for blood urea nitrogen (BUN), creatinine, and hematocrit were drawn prior to treatment (baseline), immediately after hypothermia and re-warming (day 2), and again at day 7 or discharge, and values compared.
  
  
  RESULTS
  On initiation of cooling, temperatures dropped from a median pre-treatment value of 36.1°C (IQR: 35.8-36.4°C) to 33.1°C (IQR: 33.1-33.4°C). Urine output decreased 5.1 ml/h for every 1°C decrease in body temperature (p-value=0.001), with no associated serious adverse events. There were no statistically significant changes in BUN, creatinine, or hematocrit in the hypothermia patients.
  
  
  CONCLUSIONS
  Inducing hypothermia in patients with relatively unperturbed renal physiology results in a decrease in urine output that is linearly correlated with the decrease in core temperature. This has important implications for fluid management in patients undergoing therapeutic hypothermia.
authors.affiliation: Department of Emergency Medicine, University of California San Diego Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8676, United States.
authors.forename: Kama Z
authors.initials: KZ
authors.lastname: Guluma
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Hemmen
authors.forename: Aninda B
authors.initials: AB
authors.lastname: Acharya
authors.forename: Karen S
authors.initials: KS
authors.lastname: Rapp
authors.forename: Rema
authors.initials: R
authors.lastname: Raman
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Lyden
mesh_terms: D000368:Aged; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D005260:Female; D006400:Hematocrit; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D007668:Kidney / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy*; D014556:Urine
chemical_list: D003404:Creatinine
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