Factors associated with unintended perianesthesia hypothermia.

Background: Our hypothesis was that total intravenous anesthesia (TIVA) is associated with an increase in hypothermia.

Methods: Inclusion criteria were patients from the National Anesthesia Clinical Outcomes Registry undergoing a general anesthetic during 2019. Data collected included patient age, sex, American Society of Anesthesiologists physical status classification system score (ASAPS), duration of anesthetic, use of TIVA, type of procedure, and hypothermia. Continuous variables were compared using Student's test or Mann Whitney rank sum as appropriate. Mixed effects multiple logistic regression was performed to determine the association between independent variables and hypothermia.

Results: There was a low incidence of hypothermia (1.2%). Patients who became hypothermic were older, had a higher median ASAPS, and had a higher rate of TIVA. TIVA patients had a significantly increased odds for hypothermia when controlling for covariates. Patients undergoing obstetrical, thoracic, or radiological procedures had increased odds for hypothermia. In a matched cohort subset, TIVA was associated with a greater rate and increased odds for hypothermia.

Conclusions: The novel and noteworthy finding was the association between TIVA and perianesthesia hypothermia. Thoracic, radiologic, and obstetrical procedures were associated with greater rates of and odds for hypothermia. Other identified factors can help to stratify patients for risk for hypothermia.