title: The impact of ambient operating room temperature on neonatal and maternal hypothermia and associated morbidities: a randomized controlled trial.
abstract: BACKGROUND
  Neonatal hypothermia is common at the time of cesarean delivery and has been associated with a constellation of morbidities in addition to increased neonatal mortality. Additionally, maternal hypothermia is often uncomfortable for the surgical patient and has been associated with intraoperative and postoperative complications. Various methods to decrease the rates of neonatal and maternal hypothermia have been examined and found to have varying levels of success.
  
  
  OBJECTIVE
  We sought to determine whether an increase in operating room temperature at cesarean delivery results in a decrease in the rate of neonatal hypothermia and associated morbidities.
  
  
  METHODS
  In this single-center randomized trial, operating room temperatures were adjusted weekly according to a cluster randomization schedule to either 20°C (67°F), which was the standard at our institution, or 23°C (73°F), which was the maximum temperature allowable per hospital policy. Neonatal hypothermia was defined as core body temperature <36.5°C (97.7°F) per World Health Organization criteria. The primary study outcome was neonatal hypothermia on arrival to the admitting nursery. Measures of neonatal morbidity potentially associated with hypothermia were examined.
  
  
  RESULTS
  From February through July 2015, 791 women who underwent cesarean deliveries were enrolled, resulting in 410 infants in the 20°C standard management group and 399 in the 23°C study group. The rate of neonatal hypothermia on arrival to the admitting nursery was lower in the study group as compared to the standard management group: 35% vs 50%, P < .001. Moderate to severe hypothermia was infrequent when the operating room temperature was 23°C (5%); in contrast such hypothermia occurred in 19% of the standard management group, P < .001. Additionally, neonatal temperature in the operating room immediately following delivery and stabilization was also higher in the study group, 37.1 ± 0.6°C vs 36.9 ± 0.6°C, P < .001. We found no difference in rates of intubation, ventilator use, hypoglycemia, metabolic acidemia, or intraventricular hemorrhage. Fever (temperature >38.0°C or 100.4°F) on arrival to the admitting unit was uncommon and did not differ between the study groups. Maternal temperature on arrival to the operating room was not different between the 2 groups, however by delivery it was significantly lower in the standard management group, 36.2 ± 0.6°C vs 36.4 ± 0.6°C, P < .001. This effect persisted, as maternal temperature on arrival to the postoperative care area was lower in the standard management group, 36.1 ± 0.6°C vs 36.2 ± 0.6°C, P < .001, and the rate of hypothermia was higher, 77% vs 69%, P = .008.
  
  
  CONCLUSIONS
  A modest increase in operating room temperature at the time of cesarean reduces the rate of neonatal and maternal hypothermia. We did not detect a decrease in neonatal morbidity, but the power to detect a small change in these outcomes was limited.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX. Electronic address: Elaine.Duryea@UTSouthwestern.edu.
authors.forename: Elaine L
authors.initials: EL
authors.lastname: Duryea
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: David B
authors.initials: DB
authors.lastname: Nelson
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Myra H
authors.initials: MH
authors.lastname: Wyckoff
authors.affiliation: Department of Anesthesia, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Erica N
authors.initials: EN
authors.lastname: Grant
authors.affiliation: Department of Anesthesia, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Weike
authors.initials: W
authors.lastname: Tao
authors.affiliation: Department of Anesthesia, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Neeti
authors.initials: N
authors.lastname: Sadana
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Lina F
authors.initials: LF
authors.lastname: Chalak
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Donald D
authors.initials: DD
authors.lastname: McIntire
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Leveno
mesh_terms: D000328:Adult; D001831:Body Temperature; D002585:Cesarean Section; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000517:prevention & control*; D007231:Infant, Newborn; D009873:Operating Rooms; D011247:Pregnancy; D013696:Temperature
keywords: ambient temperature; cesarean; warming