Risk factors for postoperative hypothermia in the post-anesthetic care unit: a prospective prognostic pilot study

BACKGROUND: Hypothermia occurs in up to 20% of perioperative patients. Systematic postoperative temperature monitoring is not a standard of care in Brazil and there are few publications about temperature recovery in the postoperative care unit. DESIGN AND SETTING: Multicenter, observational, cross-sectional study, at Hospital de Base do Distrito Federal and Hospital Materno Infantil de Brasília. METHODS: At admission and discharge from postoperative care unit, patients undergoing elective or urgent surgical procedures were evaluated according to tympanic temperature, vital signs, perioperative adverse events, and length of stay in postoperative care unit and length of hospital stay. RESULTS: 78 patients, from 18 to 85 years old, were assessed. The incidence of temperatures <36 °C at postoperative care unit admission was 69.2%. Spinal anesthesia (p < 0.0001), cesarean section (p = 0.03), and patients who received morphine (p = 0.005) and sufentanil (p = 0.003) had significantly lower temperatures through time. During postoperative care unit stay, the elderly presented a greater tendency to hypothermia and lower recovery ability from this condition when compared to young patients (p < 0.001). Combined anesthesia was also associated to higher rates of hypothermia, followed by regional and general anesthesia alone (p < 0.001). CONCLUSION: In conclusion, this pilot study showed that perioperative hypothermia is still a prevalent problem in our anesthetic practice. More than half of the analyzed patients presented hypothermia through postoperative care unit admission. We have demonstrated the feasibility of a large, multicenter, cross-sectional study of postoperative hypothermia in the post-anesthetic care unit.