The Effect of Preoperative Active Warming on Intraoperative Body Temperature

The Effect of Active Warming Before Total Knee Arthroplasty on Intraoperative Body Temperature and Comfort: A Randomized Control Trial

A randomized controlled study was conducted to examine the effect of active warming before total knee arthroplasty on intraoperative body temperature and comfort.

Inadvertent perioperative hypothermia is defined as a patient's internal temperature below 36 °C in surgical settings. All patients undergoing surgery and other invasive procedures are at risk of developing undesirable hypothermia. Both general and neuraxial anesthesia greatly impair thermoregulatory control, and as a result, unwarmed surgical patients become hypothermic. General and regional anesthesia causes undesirable hypothermia as a result of the redistribution of body temperature from the center to the periphery. In the perioperative period, patients over 60 years of age with poor nutritional status, low core temperature before surgery, preoperative fasting and fluid deprivation before anesthesia, premedication, type of surgery, dry and cold anesthetic gases, cold intravenous fluids, flushes, blood products (cold fluids direct core temperature) Hypothermia is caused by low ambient temperature, wet skin, dressings or sheets, anesthetic agents, large open cavity or abdominal surgery, excessive blood loss, drugs used before surgery. There are many methods to maintain the body temperature of patients (passive isolation methods) or to warm the patient (active warming methods). Passive insulation methods include heated cotton blankets, surgical drapes, and thermal suits. Active heating techniques include compressed air heaters, electric heating blankets, and heated liquids and gases. In the literature, studies on active and passive heating methods have been found in order to prevent undesirable hypothermia. There are studies with stand-alone active heating methods (such as pressurized hot air blowing systems, heated liquids, circulating hot water systems) and combined methods. Because the results of these studies were different, a randomized controlled study was planned to investigate the effectiveness of the prewarming intervention, to support the surgical process nurses in clinical practice, and to increase the reliability of the results, before developing a procedure related to prewarming. In the study, the effect of prewarming with a hot air blowing system before the surgical procedure on the patients who will undergo total knee arthroplasty, on the patient's body temperature during the operation and on the comfort in the early postoperative period will be determined.

Patients in the intervention group will be prewarming with a hot air blowing system for 30 minutes before the operation. The patients will continue to be warmed with a carbon fiber heating bed, which is a resistive system, during the surgery.

The patients will continue to be warmed with a carbon fiber heating bed, which is a resistive system, during the surgery.

When patients in the study group come to the Preoperative Care Unit (PCU), their body temperature will be measured. Patients in the study group will be placed in such a way that the 3M™ Bair Hugger™ Whole Body Blanket covers the patient's body and prewarmed with the 3M™ Bair Hugger™ Warming Unit for 30 minutes before anesthesia is given in the PCU. Heating unit temperature will be adjusted to 43°C in line with company recommendations. After the patients in the study group are warmed up for 30 minutes, the preheating process will be completed and the whole body blanket will be taken and the blankets that the clinic routinely use for each patient will be covered to cover the patients' body.

During the operation, the body temperature of the patients will be measured at 15-minute intervals from the beginning of the incision to the end of the operation. Patients' body temperature will be measured tympanically using Braun ThermoScan® 7 Age Precision®.

Temperature Comfort Perception Scale: Verbal Numeric Rating Scale (VNRS) between 1 and 10 (0=very comfortable; 10=very uncomfortable) will be used to objectively evaluate the temperature comfort perception of the patients.

Body temperatures will be measured at 15-minute intervals until patients arrive at the Postanesthesia Care Unit and are sent to the clinic.

Until admission to the Postanaesthesia Care Unit and sent to the clinic (min.15 minutes) (max.30 minutes)

Temperature Comfort Perception Scale: Verbal Numeric Rating Scale (VNRS) between 1 and 10 (0=very comfortable; 10=very uncomfortable) will be used to objectively evaluate the temperature comfort perception of the patients.

The comfort levels of the patients who are decided to be taken from the PACU to the clinic will be measured with the Perianesthesia Comfort Scale. The highest total score that can be obtained from the scale is 144, and the lowest total score is 24. The average value is determined by dividing the total score obtained by the number of scale items, and the result is indicated in the 1-6 distribution. Low score indicates bad comfort, high score indicates good comfort.

Inclusion Criteria: Patients who volunteered to participate in the study Elective surgery planned Patients between the ages of 18-80 ASA I-III Neuroaxial anesthesia applied No sensory problems (hearing, vision) No psychiatric illness 18.5<BMI<39.9 kg/m2 Exclusion Criteria: Body temperature <36°C at the entrance to the operating room Preoperative body temperature <36°C Patients who develop complications during preheating (blood pressure rise, patients are uncomfortable with the heat, they are agitated) Peripheral vascular disease Patients with communication difficulties Patients with infectious disease

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