Free Flap Temperature Homeostasis during Microsurgery: Benefits of the “Microsurgical Duvet”

The importance of postoperative flap monitoring following microsurgery, including maintenance and monitoring of peripheral temperature, is well documented.[1] However, the significance of appropriate intraoperative temperature regulation of the patient may often be overlooked, even though intraoperative hypothermia is associated with a higher risk of postoperative complications.[2] Thermoregulation is disrupted by general anesthesia, a fact that is compounded during lengthy, complex reconstructive procedures. Contributing factors include the exposure of the patient to the cool ambient environment within the operating room (with conductive, convective, and radiant thermal transfer), exposure of surgical wounds to room air (causing evaporative cooling) and the administration of cooled intravenous fluids.

Both the surgeon and anesthetist have responsibility for controlling the intraoperative environment. Hypothermia poses a significant threat to peripheral perfusion, plasma viscosity, and metabolic stability, thus maintenance of a minimum core temperature of 36.0°C is considered paramount.[3] It has been recommended that the differential between the core and peripheral temperature should not exceed 2.0°C.[4] The use of warming adjuncts is invaluable.[5] These include warmed, humidified anesthetic gases, warmed intravenous fluids, an increase in ambient operating room temperature, as well as a warming blanket (e.g., Bair Hugger, Arizant Healthcare Inc., Eden Prairie, MN), pad (e.g., Operatherm, KanMed AB, Bromma, Sweden), or mattress (e.g., WarmCloud, KanMed AB, Bromma, Sweden). The ambient temperature of the operating room should be maintained in the order of 24°C.[6] [7]

Furthermore, the prolonged exposure of surgical wounds to the operating room environment increases the risk of patient cooling, tissue desiccation, and bacterial contamination.[8] Covering the wound with a sterile drape or equivalent could minimize these risks. For the past decade, the senior author (C.N.M.) has used a “microsurgical duvet” to cover the exposed (i.e., undraped) areas of the patient during microsurgery. The aim of this study is to determine whether use of the “microsurgical duvet” causes a measurable improvement in peripheral skin temperature in healthy controls.

• References

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• 2 Sumer BD, Myers LL, Leach J, Truelson JM. Correlation between intraoperative hypothermia and perioperative morbidity in patients with head and neck cancer. Arch Otolaryngol Head Neck Surg 2009; 135 (7) 682-686
• 3 Jakubowski M, Lamont A, Murray WB, de Wit SL. Anaesthesia for microsurgery. S Afr Med J 1985; 67 (15) 581-584
• 4 Hagau N, Longrois D. Anesthesia for free vascularized tissue transfer. Microsurgery 2009; 29 (2) 161-167
• 5 Robins DW. The anaesthetic management of patients undergoing free flap transfer. Br J Plast Surg 1983; 36 (2) 231-234
• 6 Pattani KM, Byrne P, Boahene K, Richmon J. What makes a good flap go bad? A critical analysis of the literature of intraoperative factors related to free flap failure. Laryngoscope 2010; 120 (4) 717-723
• 7 Gardiner MD, Nanchahal J. Strategies to ensure success of microvascular free tissue transfer. J Plast Reconstr Aesthet Surg 2010; 63 (9) e665-e673
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• 9 Awwad AM, White RJ, Webster MH, Vance JP. The effect of temperature on blood flow in island and free skin flaps: an experimental study. Br J Plast Surg 1983; 36 (3) 373-382