The Effect of Menstrual Cycle on Postanesthetic Shivering; Prospective Observational Study

Postoperative shivering is a protective mechanism that the body uses to raise body temperature by rhythmic muscle contractions during hypothermia. Peroperative hypothermia is the most important cause of shivering after recovery. Shivering not only causes a decrease in patient comfort and discomfort but also increases metabolic demand by increasing oxygen consumption. This is an undesirable situation.

Women's hormonal status affects body temperature control. During the luteal phase, progesterone levels increase and this results in a 0.4 °C increase in core body temperature. The threshold for vasodilation also increases during this phase. Therefore, thermoregulation also changes during the luteal phase. Core body temperature in the follicular and luteal phase does not change with exposure to cold. However, under general anesthesia, core temperature is significantly reduced in both the luteal and follicular phase. Thermoregulatory vasoconstriction is less inhibited during luteal phase anesthesia.

The primary aim of our study was to determine the relationship between different phases of the menstrual cycle and the frequency of postoperative shivering. The secondary aim was to evaluate the incidence of intraoperative hypothermia and the duration of onset of intraoperative hypothermia in different phases of the menstrual cycle.

The study is planned as a prospective cross-sectional observational study. Female patients aged 18-45 years with ASA (American Society of Anesthesiology) score I-II who will undergo elective surgery for open technique septoplasty or rhinoplasty will be included in the study. They will be recorded in two groups as follicular group (F) and luteal group (L).

Patients data will be recorded;