Investigation of the Effect of Reflective Blanket on Reducing the Development of Undesirable Perioperative Hypothermia

Undesirable perioperative hypothermia (UPH) is a decrease in the core body temperature, expressed as the temperature of the blood and internal organs, below 36°C. UPH is an important complication of -anesthesia- and surgery and can occur during the period from the preoperative period (1 hour before anesthesia) to the postoperative period (the first 24 hours after anesthesia). There is a risk of developing UPH in all patients who will undergo surgery.

The application of general anesthesia, the cold environment of the operating room, the openness of the operated internal body region to ambient temperature, the long duration of the operation, the use of unheated IV fluids and irrigation fluids contribute to the development of UPH. Body temperature loss occurs rapidly with four mechanisms in the form of radiation, conduction, convection and evaporation before anesthesia and after anesthesia induction.

UPH causes many undesirable negative consequences for the patient. The deterioration of these patient comfort, flicker, myocardial problems, wound infection, wound healing problems, postoperative pain, platelet dysfunction, increased blood loss and blood transfusion requirements, renal function deterioration, a decrease in drug metabolism, anesthesia, post-operative care unit and prolong the length of stay in hospital and is expressed in the increase of mortality.

In the perioperative process, two methods are used to warm patients in the form of active and passive heating (insulation). Active heating, hot air blown systems, electric drapes (resistive systems), radiant heaters, intravenous fluids, blood, blood-product heaters, heat and moisture exchanger, filters, heating methods include negative pressure. While systems with hot air blowing reduce heat loss by radiation, they also provide temperature increase by convection. Heating devices should be used together with special suitable blankets and these blankets should cover as much of the body as possible. Cotton-wool blankets, socks, surgical drapes or plastic drapes with metal additives are used for passive heating. The effect of passive insulation is directly proportional to the area covered. Passive heating is recommended to prevent hypothermia in patients with a body temperature of 36 °C and above, and active heating is recommended in patients with a body temperature of less than 36°C.

It is stated that patients who are scheduled for general anesthesia should be warmed up for at least 10-20 minutes before surgery.The combination of more than one heating technique to ensure normothermia increases the effectiveness. Heating with hot air blowing devices is a widespread and effective approach to achieving normothermia and patient satisfaction. The superiority of these devices has been proven in many studies. On the other hand, providing a heating unit for each patient both in the operating room and in the post-anesthesia care unit will cause a serious cost increase.