Core temp <36°C increases infection, blood loss, and cardiac events. Measure temperature and warm early, especially in long cases and frail patients.
Heat loss mechanisms
- Radiation largest in cold theatre
- Evaporation from exposed viscera and skin prep
- Conduction to cold surfaces, convection from air flow
Consequences
- Coagulopathy and transfusion need
- Prolonged drug metabolism (vecuronium, propofol)
- Shivering increases O2 consumption
- SSI risk after colon surgery (evidence)
36 C or above
- Maintain active warming
- Warm IV fluids
- Monitor in long cases
35 to 36 C
- Forced air warming
- Warm fluids, raise room temperature
- Delay elective surgery if under 36
Under 35 C
- Coagulopathy, arrhythmia, SSI risk
- Active rewarming, continue in PACU
- Look for other causes
Prevention bundle
1
1. Pre-warm
Forced air warming in holding area 15 to 30 min when feasible.
Forced air warming in holding area 15 to 30 min when feasible.
↓
2
2. Intraop
Upper body forced air, warmed IV fluids, increase room temp when acceptable.
Upper body forced air, warmed IV fluids, increase room temp when acceptable.
↓
3
3. Monitor
Nasopharyngeal or oesophageal probe for core temp in moderate/long cases.
Nasopharyngeal or oesophageal probe for core temp in moderate/long cases.
↓
4
4. Rewarm
Continue warming in PACU until normothermic.
Continue warming in PACU until normothermic.
Who is high risk
- Elderly, BMI low, large surface exposure
- Regional plus GA, long laparotomy
Pitfalls
- Blanket alone without active warming
- Cold irrigation without measurement
MedPrep - www.medprep.uk - Educational revision aid only. Not clinical guidance. Doses are adult examples; check the BNF, current guidelines and local policy, and seek senior advice. Nov 2026