title: Age-related thermoregulatory differences in a warm operating room environment (approximately 26 degrees C).
abstract: Inadvertent hypothermia occurs frequently at typical ambient operating room (OR) temperatures, especially in elderly patients receiving general anesthesia. The aims of the current study were to 1) determine the incidence and magnitude of core hypothermia in an unusually warm OR environment, and 2) to assess age-related differences in perioperative thermoregulatory responses under these circumstances. Forty patients receiving general anesthesia for orthopedic surgical procedures (20 younger patients, 20-40 yr old) and (20 older patients, 60-75 yr old) were enrolled. Mean ambient temperature in the ORs was 25.8 degrees +/- 0.2 degrees C. Core temperature, vasoconstriction, and shivering were compared in the younger and older age groups. Mean core temperature on admission to the postanesthesia care unit was not significantly different in the younger (36.7 degrees +/- 0.1 degrees C) and older (36.4 degrees +/- 0.1 degrees C) age groups. Only 10% of patients (n = 4, 1 younger, 3 older) were admitted with a core temperature <36.0 degrees C. Only 2% of patients (n = 1, older group) had a core temperature <35.5 degrees C. This very mild degree of hypothermia was associated with postoperative vasoconstriction in 80% of the younger and 55% of the older patients (P = 0.18). Postoperative shivering occurred in 40% of the younger patients and in 10% of the older patients (P = 0.06). In summary, an ambient OR temperature near 26 degrees C (79 degrees F) is effective in preventing core hypothermia during general anesthesia regardless of patient age. Even very mild postoperative hypothermia may initiate thermoregulatory responses.
  
  
  
  By increasing ambient temperature in the operating room to 26 degrees C (79 degrees F), the incidence of core hypothermia can be dramatically reduced in both younger and older patients.
authors.affiliation: Department of Anesthesiology and Intensive Care, Alexandria University, Alexandria, Egypt.
authors.forename: N
authors.initials: N
authors.lastname: El-Gamal
authors.forename: N
authors.initials: N
authors.lastname: Elkassabany
authors.forename: S M
authors.initials: SM
authors.lastname: Frank
authors.forename: R
authors.initials: R
authors.lastname: Amar
authors.forename: H A
authors.initials: HA
authors.lastname: Khabar
authors.forename: H K
authors.initials: HK
authors.lastname: El-Rahmany
authors.forename: A S
authors.initials: AS
authors.lastname: Okasha
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001833:Body Temperature Regulation; D006801:Humans; D007035:Hypothermia / Q000209:etiology; D008875:Middle Aged; D009873:Operating Rooms; D014661:Vasoconstriction