title: Influence of Peri-Operative Hypothermia on Surgical Site Infection in Prolonged Gastroenterological Surgery.
abstract: BACKGROUND
  There have been several recent studies on the correlation between intra-operative hypothermia and the occurrence of surgical site infection (SSI). Differences in the depth and timing of hypothermia and the surgical procedure may have led to conflicting results.
  
  
  METHODS
  Patients undergoing gastroenterologic surgery with a duration of >3 h were analyzed. Hypothermia was defined as a core temperature <36°C and was classified as mild (35.5-35.9°C), moderate (35.0-35.4°C), or severe (<35.0°C). Hypothermia also was classified as early-nadir (<36°C within two h of anesthesia induction) and late-nadir (after that time). Risk factors for SSIs were analyzed according to these classifications.
  
  
  RESULTS
  Among 1,409 patients, 528 (37.5%) had hypothermia, which was classified as mild in 358, moderate in 137, and severe in 33. Early-nadir and late-nadir hypothermia was found in 23.7% and 13.8%, respectively. There was no significant difference in the incidence of SSIs between patients with and without hypothermia (relative risk 1.00; 95% confidence interval [CI] 0.80-1.25; p = 0.997). However, there was a significantly greater incidence of SSIs in patients with severe hypothermia (33.3%) than in those with normothermia (19.2%; p = 0.045) or mild hypothermia (17.0%; p = 0.021). The incidence of SSIs also was significantly greater in patients with late-nadir than in those with early-nadir hypothermia (23.7% vs. 16.5%; p = 0.041). The incidence of organ/space SSIs was significantly greater in patients with late-nadir hypothermia (19.6%) than in patients with normothermia (12.7%; p = 0.012). In multivariable analysis, neither severe hypothermia (odds ratio 1.24; 95% CI 0.56-2.77] nor late-nadir hypothermia (OR 0.71; 95% CI 0.46-1.01) was an independent risk factor for SSIs.
  
  
  CONCLUSIONS
  Severe and late-nadir hypothermia were associated with a greater incidence of SSIs and organ/space SSIs. However, neither of these patterns was identified as an independent risk factor for SSIs, possibly because of the small number of patients.
authors.affiliation: 1 Department of Nursing, Hyogo University of Health Sciences , Hyogo, Japan .
authors.forename: Toshie
authors.initials: T
authors.lastname: Tsuchida
authors.affiliation: 2 Infection Control and Prevention, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takesue
authors.affiliation: 2 Infection Control and Prevention, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ichiki
authors.affiliation: 2 Infection Control and Prevention, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Takashi
authors.initials: T
authors.lastname: Uede
authors.affiliation: 2 Infection Control and Prevention, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: 3 Department of Surgery, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ikeuchi
authors.affiliation: 3 Department of Surgery, Hyogo College of Medicine , Hyogo, Japan .
authors.forename: Motoi
authors.initials: M
authors.lastname: Uchino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000145:classification / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D013530:Surgical Wound Infection / Q000453:epidemiology*; D055815:Young Adult