A daily debate rages between orthopaedic surgeons, anesthesiologists, and operating room (OR) personnel regarding OR temperature. While surgeons may perspire profusely under the bright lights of the OR and request that the room temperature be lowered, anesthesiologists and other personnel routinely prefer that the temperature remain higher, arguably to limit morbidity. But what impact does the ambient room temperature actually have on the patient and the 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. Most importantly, the authors found that there was no correlation between decreasing room temperature and a lower patient core temperature (p = 0.44). These results are especially noteworthy given that trauma patients are likely to be much more physiologically fragile than patients undergoing elective surgery. Therefore, there is little support for raising the OR temperature in an effort to lessen patient morbidity13. However, there is compelling evidence to the contrary, as increased temperatures have been correlated with increased risk of infection and decreased surgical efficiency.
Surgeon perspiration has been associated with a theoretical increased risk of infection14. In a clinical study, 10 surgeons were asked to perform a simulated total hip arthroplasty at a room temperature that did not induce sweating, and then subsequently perform the same procedure while sweating. Twice as many units of bacteria were isolated during the procedure with sweating (6.9 compared with 3.3, p < 0.05)14. The authors hypothesized that there are several mechanisms through which a sweating surgeon may contaminate the surgical field, including sweat through the surgical gown, sweat droplets falling directly onto the field, and exposure of exfoliated skin, particularly in a surgical field with increased air movement. They concluded that the OR temperature should be kept cool to mitigate the risk of infection14. In addition to the aforementioned mechanisms of contamination, bacterial permeability of surgical gowns also has been demonstrated with both reusable and disposable models15, and OR temperatures of >20°C (68°F) have been associated with a higher degree of bacterial colonization on the surface of surgical gowns16, further facilitating compromise of the surgical field. Based on these findings, we recommend maintaining the OR temperature at ≤20°C to mitigate against bacterial growth on all members of the surgical team.
Not only does an increased room temperature pose a very tangible risk to the patient, but it may directly impact the surgeon’s mental and physical capabilities in the OR. Cognitive performance17,18 and reaction time19 in the general population have been shown to be negatively affected by even small increases in ambient temperature. Wyon et al. published a landmark study in 1968 in which they found that at temperatures of ≤19°C (66°F), 95% of surgeons reported feeling comfortable with the OR temperature20. Among surgeons, a more recent 2015 study evaluated performance on the validated Surgical Task Load Index at either 19°C (66°F) or 26°C (79°F). After 10 minutes of acclimatization, they found nearly twice as many errors on peg transfer and knot tying tasks (7% compared with 4%, respectively) with surgeons in the 26°C group. The 26°C group also had significantly greater workload and distractions while completing the 5-minute task after acclimation21. The amount of time that the surgeons were exposed to the 2 environments in this study was relatively short, but still had a significant impact on the surgeons completing the task. During surgery, distractions occur frequently and may have a cumulative effect on the focus of the surgeon, which has been shown to have a negative impact on overall performance22-24. Given that OR temperature is a modifiable risk, it should be addressed, especially during more physically demanding surgeries or those necessitating lead-gown use for protection against radiation exposure. Thus, for surgeon comfort and focus, we advocate maintaining temperatures at or below 19°C at baseline.
Patient safety is of paramount importance for all health-care providers, and the complexity of the perioperative environment demands evidence-based optimization of care rather than arbitrarily imposed policies. The association between room temperature and patient core temperature is weak, and as a result, increasing OR temperature, especially for short elective cases, has been shown to have a potentially deleterious effect on the patient by amplifying the risk of infection, reducing surgical efficiency, and increasing surgical error. As orthopaedic surgeons, we advocate for (1) preoperative warming of patients in the holding area to help reduce intraoperative hypothermia, (2) intraoperative warming with a forced-air warming system, (3) goal OR temperatures of ≤19°C to optimize surgeon performance and minimize infection risk, and (4) an open dialogue with the surgical team, including anesthesia providers, about the expected duration of the case and the health of the patient12-24.
Investigation performed at the Department of Orthopaedic Surgery and Rehabilitation, William Beaumont Army Medical Center, El Paso, Texas
Disclosure: The authors indicated that no external funding was received for any aspect of this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/A155).
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