Hypothermia; Anesthesia, Perfusion Index
Conditions
Keywords
Cross sectional, Observational, Hypothermia, Anaesthesia, Anesthesia, General Anaesthesia, General Anesthesia, General surgery
Brief summary
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.
Detailed description
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.
Interventions
DIAGNOSTIC_TESTPerfusion index
The perfusion index (PI) is defined as the ratio of pulsatile light absorption to continuous light absorption, denoted as AC/DC. Initially used as a quality signal indicator in pulse oximetry, PI has increasingly been recognized for its potential in non-invasive hemodynamic monitoring. Since PI changes with peripheral blood flow, it may reflect peripheral temperature gradients and, consequently, thermoregulatory responses like peripheral vasoconstriction. Studies have reported that the core-to-peripheral temperature difference correlates with peripheral PI. The findings suggest that both peripheral and core temperatures contribute to the threshold for shivering and that PI reflects the vasoconstriction induced by thermoregulatory responses that precede shivering
Sponsors
Ain Shams University
Study design
Observational model
COHORT
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| To measure the change of PI associated with change in core and peripheral body temperatures as measured by the oropharyngeal probe and the pattern of this change | Through study completion, 3 months from April 2024 to June 2024 | The PI was recorded by attaching a sensor to the patient's finger (Ultralife Pulse Oximeter JPD-500D). The baseline body temperature (T1) was measured using a Granzia GT-3 Digital thermometer. Subsequently, the PI was recorded and assessed every 15 min until completion of the surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| To detect the change of PI with the change in temperature gradient (it is defined as the difference between the skin temperature and the core temperature) | Through study completion, 3 months from April 2024 to June 2024 | — |
| To detect the incidence of a low reading of PI and the increase in serum lactate level in an arterial blood gases sample. | Through study completion, 3 months from April 2024 to June 2024 | A baseline ABG (B1) was drawn, and serum lactate value was recorded. A follow up ABG (B2) was drawn at PI values \<0.2%, and serum lactate was recorded again. |
Countries
Egypt
Outcome results
None listed