Kongsayreepong et al identified risk factors for core hypothermia in a patient admitted to the surgical intensive care unit following surgery. These can help identify a patient who may require interventions to prevent or reverse hypothermia. The authors are from Siriraj Hospital and Mahidol University in Bangkok, Thailand.


Criteria for core hypothermia: temperature < 36°C


Risk factors increasing the risk of hypothermia:

(1) high ASA physical status (risk greatest if ASA >= III, risk for ASA II > ASA I)

(2) magnitude of the operation (risk greatest if major surgery; risk medium > minor)

(3) use of combined epidural and general anesthesia

(4) duration of surgery > 2 hours

(5) not monitoring temperature during the procedure


Protective factors reducing the risk of hypothermia:

(1) high body weight and greater body surface area

(2) higher preoperative temperature

(3) warmer operating room temperature


Mortality in the patients was increased if:

(1) ASA >= II

(2) emergency surgery

(3) > 2 days in the ICU

Hypothermia was not an independent risk factor, but was associated with these.


Of these variables the only ones which the physician has any control:

(1) duration of the surgery

(2) temperature of the operating room

(3) monitoring of temperature during surgery

(4) type of anesthesia selected


Other factors that could reduce hypothermia:

(1) use of fluid warmer, especially with blood transfusion

(2) use of a patient warming device


For the implementation:

(1) An ASA >= III or major operation were high risk for hypothermia.

(2) An ASA = II, medium surgery, use of combined anesthesia, > 2 hours, failure to monitor, low body weight, low preoperative temperature, and cooler operating room temperature were taken as moderate risk factors.


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