The Sweaty Surgeon: Raising Ambient Operating Room Temperature Benefits Neither Patient nor Surgeon
Hypothermia, defined by a core temperature <36°C (96.8°F), has been associated with increased morbidity in surgery1. Specifically, patient discomfort2, increased cardiac events3, increased blood loss4,5 secondary to impaired coagulation enzyme function6, increased risk of infection7,8, poor wound-healing8, and prolonged care in the postanesthesia care unit9 have been correlated with patient hypothermia in nonorthopaedic patients. However, an important question is whether increasing the room temperature actually reduces the risk of hypothermia. Furthermore, what are the possible unforeseen negative consequences of increasing the room temperature?
To answer this question, we performed a comprehensive literature search of the PubMed, MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, and Embase databases for all articles published between January 1, 1990, and June 5, 2016, that included the following terms: (1) operating room temperature, (2) operating room hypothermia, (3) ambient operating room temperature, (4) surgeon concentration, (5) temperature and cognition, and (6) surgery hypothermia. This initial query yielded a total of 72 original articles that we reviewed for their relevance to temperature in the OR as it pertains to patients and surgeons.
Based on this review, we found that there are several reasons to be skeptical of the literature regarding hypothermia and patient complications in orthopaedic surgery. First, none of the published studies exclusively involved orthopaedic patients, so the relationship between intraoperative hypothermia and complications in the orthopaedic patient has not been demonstrated. Second, the published studies show a correlation between temperature and complications, but these studies do not establish cause and effect. Third, there are some studies that suggest that higher OR temperatures in orthopaedic cases might lead to higher infection rates.
Up to two-thirds of trauma patients present to the emergency department in a hypothermic state10,11. As a result, OR staff often have more difficulty controlling the core temperature in this cohort. The correlation between room temperature and patient core temperature has been scrutinized in some studies12,13. In 1 prospective investigation, patients undergoing total joint arthroplasty were randomized into a warm OR (24°C [75.2°F]) or a standard-temperature OR (17°C [62.6°F])12. After the patient had been covered in a forced-air warming system and warm blankets, the surgery commenced and all of the ORs were lowered to the standard temperature. At the start of the procedure, the experimental group had a minimally, albeit significantly, warmer core temperature (+0.31°C [0.55°F]) than the group in ORs at the standard temperature. However, at the conclusion of the case, the 2 cohorts had equal core temperatures (36.35°C and 36.16°C, respectively). The authors concluded that prewarming the OR did not appear to offer any benefit to the patient, especially with stable patients undergoing elective orthopaedic procedures.
In another prospective analysis conducted at the Los Angeles County Medical Center that looked at all trauma patients, including nearly 20% with substantial orthopaedic injuries, ambient OR temperature was compared with intraoperative core patient temperature every 5 minutes13. Additionally, the status of the hypothermic patients was compared with patients with normothermic core temperatures (≥36°C [96.8°F]). While preoperative and postoperative hypothermia (≤35°C [95°F]) were determined to be a risk factor for mortality, this was deemed correlational and not causational.