Intraoperative hypothermia is a common and potentially severe complication during major surgical procedures. The consequences of intraoperative hypothermia can be far-reaching, affecting patient outcomes, recovery times, and overall healthcare costs. Therefore, strategies aimed at preventing hypothermia are of paramount importance in modern surgical practice. However, despite all the measures taken, some patients may still become hypothermic at the end of surgery. Understanding these factors can enhance the quality of daily practice. Medications used intraoperatively can decrease the threshold for vasoconstriction, and some of them have been reported to influence thermoregulation. For example, ephedrine is a sympathomimetic amine used to maintain hemodynamic stability, but there is a report about its thermogenic effect. One study found that patients who received an intraoperative infusion of ephedrine had a significantly lower decrease in core temperature and these patients had a more stable hemodynamic profile. It was employed in obese patients for its thermogenic and appetite-suppressing effects until its adverse effects prevented its use. Ephedrine has an unintended yet significant effect on body temperature regulation, which has raised questions about its role in contributing to the incidence of hypothermia in the postoperative period. The purpose of this study is to investigate the potential relationship between the intraoperative use of ephedrine and the incidence of hypothermia following major surgery.

This study aims to investigate the potential relationship between the intraoperative use of ephedrine and the incidence of hypothermia following major surgery. The primary goal is to determine the effect of intraoperative ephedrine use on the incidence of hypothermia after major surgery. The secondary goal is to identify patient characteristics associated with an increased risk of hypothermia despite all measures taken. The results of this study could have important implications for the quality of care for patients undergoing major surgery.

Inclusion Criteria:

• all adult patients (age 18 years) who received ephedrine during general anesthesia undergoing major surgical procedures

Exclusion Criteria:

• Patients undergoing minor surgical procedures
• Patients scheduled for day surgeries
• Patients patients (those under the age of 18)
• Patients with a history of thyroid disease
• Patients undergoing brain surgery
• Patients undergoing radiological interventions,
• Trauma patients
• Patients directly transferred from the intensive care unit to the operating room
• Patients with preoperative fever (either low or high)
• Patients who have received vasoactive agents within 24 hours before surgery
• Patients with sepsis and/or septic shock, or fever within a week before surgery
• Patients who have received vasoactive agents

This observational study was conducted over a span of four years, from January 2020 to 2023,