The Effect of Active Warming During General Anaesthesia on Postoperative Body Temperature, Shivering and Thermal Comfort

Adult patients who undergo surgery under general anaesthesia often experience inadvertent perioperative hypothermia. This common problem has serious consequences such as surgical site infection, coagulopathy, increased need for transfusion, altered drug metabolism and adverse cardiac events. Perioperative guidelines recommend warming the patient with a forced-air warming device and administering warmed intravenous and irrigation fluids to prevent intraoperative hypothermia. This study aims to investigate the effects of individual and combined use of intraoperative forced-air warming and warmed intravenous and irrigation fluids on postoperative body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients receiving general anaesthesia.

Background: Adult patients who undergo surgery under general anaesthesia often experience inadvertent perioperative hypothermia. This common problem has serious consequences such as surgical site infection, coagulopathy, increased need for transfusion, altered drug metabolism and adverse cardiac events. Perioperative guidelines recommend warming the patient with a forced-air warming device and administering warmed intravenous and irrigation fluids to prevent intraoperative hypothermia.

Objective: This study aims to investigate the effects of individual and combined use of intraoperative forced-air warming and warmed intravenous and irrigation fluids on postoperative body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients receiving general anaesthesia.

Design and setting: This is a single centre randomised controlled clinical trial. A 2 x 2 factorial design will used in the experiment. Eligible patients will be randomly assigned to one of four groups.

Methods: After the induction of anaesthesia, forced-air warming as well as warmed intravenous (IV) and irrigation fluids will be applied to the first group, the second group will be warmed with only forced-air warming device, the third group will receive only warmed intravenous and irrigation fluids, and the fourth group will consist of the control group without any intervention. Blood and blood products to be applied intraoperatively to all groups will be heated to 37°C. The primary outcome measures are postoperative body temperature, shivering, thermal comfort, pain, nausea and vomiting. The primary results will be subjected to a two-way analysis of variance for covariants such as ambient temperature and volume of intraoperative fluids.

Participants: The trial will include patients aged ≥18 years who underwent surgery under general anaesthesia, whose duration of surgery was \>1 hour, who belong to the class of American Society of Anesthesiologists I-III, who do not have any disability that would make communication difficult, and who provide written informed consent to participate in the study.

Discussion: The trial is designed to validate the effectiveness of these two interventions administered alone and in combination in maintaining perioperative normothermia and to assess whether they translate into improved patient outcomes.

\* This trial is being carried out as Marmara University Institute of Health Sciences Doctorate Thesis in Nursing.

Funding: No funding

Eligibility Criteria:
Inclusion Criteria:

Being over the age of 18 Receiving general anesthesia, surgery time ≥ 1 hour in the American Society of Anesthesiologists (ASA) I-III class Not having any obstacle to make communication difficult İnformed written consent to participate in the study.

Exclusion Criteria:

Having surgery with local anesthesia Preoperative body temperature ≥38 0C or \<36 0C Unapplied therapeutic hypothermia during the operation, Systemic infection in the patient, Mental retardation, Serious head injury, Brain damage disruption in temperature regulation, Taking medication to affect thermoregulation Unapplied IV fluids up to one hour before anesthesia induction.

Exclusion criteria is exitus and worsening for any reason in the general condition during and after the surgery.