Hypothermia During Surgery Affects Recovery

Transient and mild intraoperative hypothermia during surgery contributes to adverse outcomes, according to a new study.

Researchers at the Cleveland Clinic (OH, USA), Chiang Mai University (Thailand), and other institutions conducted a study to evaluate body temperature patterns in warmed surgical patients, and determine whether even short periods of low temperature increased blood loss or prolong hospital stays. The researchers measured intraoperative core body temperature patterns in 58,814 adults in surgery lasting more than one hour who were warmed with forced air. Independent associations between hypothermic exposure and transfusion requirement and duration of hospitalization were evaluated.

The results showed that 64% of surgical patients became hypothermic, with core temperatures below 36 °C during the first hour of anesthesia. Nearly half of the patients had a continuous core temperature less than 36 °C for more than one hour, and 20% of the patients had a continuous core temperature below 36 °C for more than two hours. Core temperatures then gradually increased, and most patients had normal temperatures by the end of surgery. The patients who became most hypothermic were most likely to need blood transfusions. The study was published in the February 2015 issue of Anesthesiology.

“Hypothermia is common during surgery because anesthetics disrupt normal control of body temperature and because operating rooms are kept cool,” said lead author Prof. Daniel Sessler, MD. “Consequently, body temperature typically decreases about four degrees Fahrenheit in unwarmed surgical patients. This sort of moderate hypothermia can cause serious complications including blood loss and wound infections.”

Forced-air warming utilizes the properties of convection and radiation to transfer heat from the movement of warm air across the surface of the patient’s skin. For more than 20 years, forced-air warming has been regarded as the standard of care to help prevent surgical site infections (SSIs) and other serious complications of unintended hypothermia, including increased blood loss, morbid myocardial events, and reduced resistance to surgical wound infections.

Related Links:
Cleveland Clinic
Chiang Mai University