Menstrual Cycle Phase May Effect the Thermoregulation during Anesthesia

Abstract

This study was registered to Australian New Zealand Clinical Trial Registry with serial number ACTRN12614000286640. After institutional review, board approval and informed consent 50 female patients; ASA (American Society of Anesthesiologists) class 1, ages between 18-45 years old were enrolled in this study. The surgeries performed were septorhinoplasty and tympanoplasty. 25 patients with menstrual cycle days from 1 to 10 (follicular group), 25 patients with menstrual cycle days from 18 to 24 (luteal group) were included in the study. Exclusion criteria were diabetes, thyroid disorders, obesity, irregular menstrual cycle and oral contraceptive usage. None of the patients was premedicated. All of the patients were monitored "Dräger infinity delta XL" to measure continuous noninvasive blood pressure, electrocardiograms, capnograms, core temperature and skin temperature. The skin temperature probe was installed in the middle of the forearm where the non-invasive blood pressure cuff was not bound. The intravenous fluid was used at the room temperature intraoperatively and fluid administration was given from the arm that skin temperature probe was not installed. The core temperature was measured with esophageal probe immediately after the intubation. The operating room temperature was maintained between 21-22 °C. Anesthesia was standardized in all patients and induced with propofol 2 mg/kg IV and rocuronium 0.5 mg/kg IV. Anesthesia was maintained with remifentanil infusion and sevoflurane in a mixture of nitrous oxide 1 L/min

Effects of Female Reproductive Hormone Levels on Inadvertent Intraoperative Hypothermia during Laparoscopic Gynecologic Surgery: A Retrospective Study

“…The present study differs from a previous study [8] on female reproductive hormones. The previous study reported only the effects of the phases of the menstrual cycle on thermoregulation under general anesthesia.…”

“…Previous studies reported that the core body temperature remained unchanged under cold exposure during the follicular and luteal phases; however, it was consistently higher in the luteal phase than in the follicular phase [7,9,10]. The core body temperature under general anesthesia was higher in the luteal phase, but it decreased significantly in both follicular and luteal phases at anesthesia reversal [8].…”

“…Many studies have reported the effects of female reproductive hormones or the menstrual cycle on thermoregulation in healthy people or in patients undergoing surgeries under general anesthesia [7][8][9][10]. Previous studies reported that the core body temperature remained unchanged under cold exposure during the follicular and luteal phases; however, it was consistently higher in the luteal phase than in the follicular phase [7,9,10].…”

“…The mechanism by which the reproductive hormones affect thermoregulatory control during the menstrual cycle in females has been described [7][8][9][10][11]. Progesterone inhibits the activity of warm-sensitive neurons, thus increasing body temperature by inhibiting heat-loss mechanisms.…”

“…In contrast, estrogen inhibits the activity of cold-sensitive neurons and stimulates the warm-sensitive neurons, thus decreasing the body temperature by inhibiting heat-retention mechanisms and activating the heat-loss mechanisms. Therefore, the phase of the menstrual cycle might affect the core body temperature under general anesthesia due to its effects on thermoregulatory control [8].…”