title: Perioperative hypothermia (33 degrees C) does not increase the occurrence of cardiovascular events in patients undergoing cerebral aneurysm surgery: findings from the Intraoperative Hypothermia for Aneurysm Surgery Trial.
abstract: BACKGROUND
  Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage.
  
  
  METHODS
  The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function.
  
  
  RESULTS
  There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038).
  
  
  CONCLUSIONS
  In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.
authors.affiliation: Department of Medicine, Kaiser San Francisco Medical Center, San Francisco, California, USA.
authors.forename: Hoang P
authors.initials: HP
authors.lastname: Nguyen
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Zaroff
authors.forename: Emine O
authors.initials: EO
authors.lastname: Bayman
authors.forename: Adrian W
authors.initials: AW
authors.lastname: Gelb
authors.forename: Michael M
authors.initials: MM
authors.lastname: Todd
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Hindman
mesh_terms: D000328:Adult; D001831:Body Temperature / Q000502:physiology; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects; D002532:Intracranial Aneurysm / Q000503:physiopathology / Q000601:surgery*; D007430:Intraoperative Care / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care / Q000009:adverse effects; D011446:Prospective Studies; D016896:Treatment Outcome