1. A 6°F increase in the temperature of the operating room was associated with a decreased rate of neonatal and maternal hypothermia following cesarean delivery.
2. There was no detected difference in neonatal morbidity.
Evidence Rating Level: 1 (Excellent)
Study Rundown: At birth, infants have a more difficult time regulating their body temperatures. Neonatal hypothermia, defined by the World Health Organization (WHO) as a body temperature below 97.7°F, is common following cesarean deliveries. Neonatal hypothermia has been associated with a host of morbidities, including low blood sugar, metabolic imbalances, brain bleeding (intraventricular hemorrhage), respiratory distress, the need for intubation, and even an increase in mortality. Cool delivery room temperatures can contribute to evaporative heat loss. In preterm infants, who are especially vulnerable, warming interventions, like radiant warmers and warmed gel mattresses, are often employed to reduce rates of hypothermia, however due to cost and inconvenience these techniques aren’t typically used in full term neonates. The WHO recommends a delivery room temperature of 77-82°F, which has been proven to decrease the risk of hypothermia in preterm infants, however operating room temperatures are often kept much cooler for surgeon comfort. In this randomized controlled trial, researchers assessed the impact of increasing the temperature of the operating room by 6°F (to 73°F) on rates of both neonatal and maternal hypothermia, as well as associated morbidities.
An increase in ambient operating room temperature was associated with a significant decrease in neonatal and maternal hypothermia following cesarean delivery, however this did not translate to a difference in neonatal morbidity. Strengths of this study included rigorous design and assessment of physician comfort as a secondary outcome. Limitations of this study included the lack of power to detect differences in rare neonatal morbidity outcomes. In the future, a large, multi-center study replicating these findings would further characterize the impact of increasing operating room temperatures and allow for detection of associations with less common outcomes.
Relevant Reading: Hypothermia and early neonatal mortality in preterm infants
In-Depth [randomized controlled trial]: Using a cluster randomization schedule, cesarean delivery operating room temperatures were adjusted to either 67°F (institution standard, n = 410 infant deliveries) or 73°F (n = 399). The primary outcome was neonatal hypothermia on arrival to the admitting nursery. Secondary outcomes included incidence of moderate to severe hypothermia (<96.8°F), maternal hypothermia and measures of neonatal morbidity. Surgeons were also surveyed, with a response rate of 86%.
Infants randomized to delivery in warmer operating rooms were less likely to develop hypothermia than those randomized to standard temperature rooms (35% vs. 50%, p<0.001). The incidence of moderate to severe neonatal hypothermia was lower in the warmer operating room (5% vs. 19%, p<0.001). This did not translate to differences in the incidence of neonatal morbidity, such as intubation, ventilator use, hypoglycemia, metabolic academia, intraventricular hemorrhage, or fever. Maternal hypothermia was also more prevalent in the control group (77% vs. 69%, p=0.008). While 21% of surgeons felt the increase in temperature affected surgical performance, 93% considered this acceptable if improved neonatal outcomes were demonstrated.
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