What are the most important risk factors for a patient's developing intraoperative hypothermia?

Anesthesiologists attempt to maintain perioperative normothermia for surgical patients. We surveyed clinical anesthesiologists and physician researchers and asked them to prioritize risk factors for a patient to develop intraoperative hypothermia. The questionnaire included 41 factors associated with changes in patient temperature identified during a computerized literature search. We asked respondents to estimate the relative importance of each risk factor on a 10-point scale. The survey was mailed to two groups: 1) 180 anesthesiologists (n = 84 respondents) randomly selected from the 1999 American Society of Anesthesiologists Members Directory and to 2) 24 physician researchers (n = 12 respondents) in thermoregulation. Researchers rated the following to be the most important risk factors for hypothermia (in sequence): neonates, a low ambient operating room temperature, burn injuries, general anesthesia with neuraxial anesthesia, geriatric patients, low temperature of the patient before induction, a thin body type, and large blood loss, The results for the clinician group were similar, because the median differences between the groups' results were two or fewer units for all items. The risk factors identified to be most important can now be further evaluated in clinical trials to develop a multivariate predictive tool for calculating a patient's a priori risk for developing hypothermia.