The Impact of Intraoperative Change in the Body Temperature on the Perfusion Index

The Impact of Intraoperative Change in the Body Temperature on the Perfusion Index: : A Cross-sectional Study

The goal of this observational study is to learn about the impact of intraoperative change in temperature in adult patients undergoing surgeries under general anaesthesia. The main question it aims to answer is:

Is the change in core body temperature reflected by changes in the prfusion index? Patients' core temperature, peripheral temperature and perfusion indices will be recorded throughout the span of the procedure.

Perioperative hypothermia increases the risk of postoperative morbidity and mortality. Almost 50-90% of the patients experience perioperative hypothermia. This involves a decrease in core temperature to ≤ 36°C, which results in an increased rate of surgical site infection, haemorrhagic tendency, and ischemic heart disease, making it a serious perioperative complication.

Early hypothermia during general anaesthesia is mainly caused by the redistribution of body heat from the central to peripheral compartments, due to vasodilation following use of the anaesthetics. The degree of redistribution of body heat may be affected by the peripheral perfusion state, which differs across patients and results in a difference in gradient between temperature of the central and peripheral compartments. Low peripheral perfusion state can lead to low peripheral body temperature, thus lowering the overall core body temperature.

It was previously reported that the risk factors for intraoperative hypothermia are age, BMI, preoperative systolic blood pressure, heart rate, baseline core temperature, ASA-PS score, the type of anaesthesia and surgery, the duration of preparation and surgery, and ambient temperature.

Previous studies did not include the PI as a risk factor for intraoperative hypothermia. Therefore, further studies are needed to assess the relationship between PI and hypothermia to generate a more accurate predictive score of perioperative hypothermia.

Inclusion Criteria:

• Patients undergoing elective surgery under general anaesthesia
• Patients aged between 20 and 70 years old.

Exclusion Criteria:

• Patients who decline to give a written informed consent.
• Patients with psychiatric disorders that lead to inability to cooperate, speak, or read.
• BMI between <20 kg/m2 or >35 kg/m2.
• Patients undergoing emergency surgeries.
• Patients with peripheral vascular disease or rheumatoid disease.