The sweet spot for an adult’s core body temperature throughout the perioperative experience is 36.5°C to 37.5°C, but maintaining this safe temperature range can be a challenge — and a safety concern, according to Lisa Spruce, DNP, RN, CNS-CP, CNOR, ACNS, ACNP, FAAN, director of evidence-based perioperative practice at the Association of periOperative Registered Nurses (AORN). “Patients can get cold while waiting for surgery in the pre-op area or they can be cold prior to coming to the facility for surgery,” explains Dr. Spruce. “Then, during the first 30 or 40 minutes after a patient receives anesthesia, their core temperature can drop due to the loss of the body’s behavioral response to anesthesia and the fact that anesthesia causes peripheral vasodilation that is associated with the loss of body heat.”
Patients whose core body temperature dips below 36°C are classified as developing unplanned hypothermia, which puts them at an increased risk of surgical site infection, poor wound healing, increased postop pain and increased length of stay in the PACU.
To counteract these effects, AORN recommends pre-warming the patient before surgery in its Guideline for Prevention of Hypothermia, which Dr. Spruce says is based on a solid collection of evidence. For example, the authors of five systematic reviews and nine randomized controlled trials recommend pre-warming the patient. Six clinical practice guidelines, including from the American Society of PeriAnesthesia Nurses and the National Collaborating Centre for Nursing and Supportive Care in the United Kingdom, recommend pre-warming as an intervention for preventing unplanned hypothermia.