1. Hypothermia and cholecystectomy Flores-Maldonado et al. 2001 290 consecutive patients 30-day follow-up Patients that received blood transfusion were excluded 35.4º±0.4ºC vs 36.2º±0.2ºC 11.5% vs 2% SSI

2. Complications and treatment of mild hypothermia Anesthesiology 2001; 95:531-43 Myocardial Ischemia Frank et al. JAMA 1997;277:1127-34 High risk patients assigned to 1.3ºC core hypothermia were three times as likely to experienced adverse cardiac outcome Cold-induced hypertension is associated with a threefold increase in plasma norepinephrine concentrations

3. Complications and treatment of mild hypothermia Coagulopathy Platelet dysfunction (reduction in the release of thromboxane A2 Clotting factor enzyme Fibrinolytic activity-TEG

4. Complications and treatment of mild hypothermia Hypothermia Impairs neutrophils function Vasoconstriction Tissue hypoxia

5. Hypothermia and SSI Vasoconstriction Decreases the partial pressure of oxygen in tissues which impairs the oxidative killing by neutrophils Reduces the deposition of collagen Impairs immunity Chemo taxis and phagocytosis of granulocytes motility of macrophages Production of antibody Reduces the production of super oxide radicals

6. Hopf et al, Arch Surg 1997 Subcutaneous oxygen tension at surrogate wound inversely correlated with the risk of SSI S/C O2 40-50mmHg had a SSI of 43% S/C O2 above 90 mmHg had no SSI

7. Complications and treatment of mild hypothermia Pharmacokinetics and Pharmacodynamics Reduces clearance during hypothermia Prolongs PACU stay

8. Minimizing hypothermia Anesthetics profoundly inhibits central thermoregulation decreasing the vasoconstriction threshold by 2-4ºC The second major factor is the magnitude of the core-to-peripheral temperature gradient Minimizing the core-to-peripheral temperature gradient and preoperative vasodilatation, is the basis to reduce heat redistribution Degree of adiposity, concurrent medication

9. Minimizing hypothermia Prewarming:Decreases core-to-peripheral temperature gradient Eventually provokes vasodilatation Pharmacologic vasodilatation

10. Laparatomy

11. Active cutaneous warming systems Forced-air systems Circulating-water mattresses Resistive heating systems (ICU,trauma) Carbon-fiber patient cover Circulating-water garments Water has a conductivity of heat 26 times higher than air Infrared radiation(neonats, pediatric Sx)

12. Fluid warming One liter of crystalloid or 1 unit of refrigerated blood decreases core temperature by 0.25ºC

13. Core temperature monitoring Pulmonary artery Nasopharynx Tympanic membrane Aural thermocouples probe Infrared thermometer Distal Oesophagus Rectal temperature during neuraxial anesthesia

15. Getting a Reading is as Easy as 1,2,3 Patient temperature readings are gathered quickly and displayed clearly

16. What is the Technique?