title: Intraoperative warming and post-operative cognitive dysfunction after total knee replacement.
abstract: BACKGROUND
  Post-operative cognitive dysfunction (POCD) can affect 30% of orthopedic surgery patients. We hypothesized that perioperative temperature has an impact on POCD.
  
  
  METHODS
  We included 150 patients over 65 years of age scheduled for total knee replacement under spinal anesthesia. They were randomized to receive standard care (sheet cover) or active warming. Neurocognitive assessment (11 subtests) was performed pre-operatively and at day 4 (three subtests) and 3 months (10 subtests). A control group of 55 nonsurgical patients took the same tests at equivalent times. POCD was defined as an individual score decrease of more than 2 standard deviations (SDs) below the baseline on at least two subtests or 2 SDs in the combined z-score, in both cases using control-adjusted changes.
  
  
  RESULTS
  Tympanic temperature declined below 35 °C in 88% of standard-care patients; 25.3% of warmed patients had a temperature ≥36 °C. On day 4, 3.2% of standard-care patients and 19.4% of warmed patients had POCD (P=0.0058). At 3 months, there were no between-group differences (standard care, 14.3%; warmed, 6.5%) (P=0.2440).
  
  
  CONCLUSIONS
  Perioperative warming was associated with a higher incidence of cognitive dysfunction at 4 days after total knee replacement in patients >65 years of age.
authors.affiliation: Department of Anesthesia, Hospital Clinic, Universitat de Barcelona, Spain. 12053fsg@comb.cat
authors.forename: F
authors.initials: F
authors.lastname: Salazar
authors.forename: M
authors.initials: M
authors.lastname: Doñate
authors.forename: T
authors.initials: T
authors.lastname: Boget
authors.forename: A
authors.initials: A
authors.lastname: Bogdanovich
authors.forename: M
authors.initials: M
authors.lastname: Basora
authors.forename: F
authors.initials: F
authors.lastname: Torres
authors.forename: N
authors.initials: N
authors.lastname: Fàbregas
mesh_terms: D000368:Aged; D016058:Analgesia, Patient-Controlled; D000775:Anesthesia, Spinal; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000523:psychology; D001831:Body Temperature / Q000502:physiology; D002097:C-Reactive Protein / Q000378:metabolism; D003072:Cognition Disorders / Q000523:psychology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007036:Hypothermia, Induced; D007430:Intraoperative Care / Q000379:methods*; D008297:Male; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000523:psychology*; D011446:Prospective Studies; D017694:Rewarming
chemical_list: D002097:C-Reactive Protein