We investigated whether the administration of 1 mg oral estazolam, 0.1 mg/kg intravenous remimazolam, or a combination of these would be beneficial for reducing preoperative anxiety and postoperative pain in gynecological patients undergoing laparoscopic surgery.
Currently, laparoscopic surgery is widely chosen by gynecologists and patients due to the associated minimal invasiveness and surgical trauma, as well as fast recovery.8,9 However, postoperative pain caused by laparoscopic surgery is still inevitable. It is generally accepted that approximately 5–30% of patients undergoing abdominal hysterectomy experience severe postoperative pain,10 which can lead to opioid abuse after surgery. Although opioids have superior analgesic effects, they are not considered ideal by some surgeons due to side effects, such as PONV, respiratory depression, and intestinal obstruction.11
Various approaches to relieving postoperative pain and reducing opioid consumption have been studied in patients undergoing various operations. The present study aimed to investigate whether postoperative pain could be alleviated by reducing preoperative anxiety. Preoperative anxiety is a preoperative psychological reaction, mainly caused by worry and fear about surgery.12 Additionally, female gender is an independent risk factor for preoperative anxiety,6 and female patients have been reported to have lower pain thresholds and to experience greater pain intensity than males.13,14 Therefore, this study selected female patients undergoing elective gynecological surgery as participants. Preoperative anxiety is closely associated with perioperative anesthesia and postsurgical management factors, including postoperative pain, anesthetic requirements, hemodynamic abnormalities, and wound healing.15
Several studies have reported that perioperative anxiety can lead to postoperative hyperalgesia. It has been observed that preoperative anxiety levels can significantly affect postoperative pain, particularly in obstetric and gynecological surgery.16,17 This may be related to the fact that female patients are more likely to have anxiety before surgery. Clinically, it has been reported that anti-epileptic drugs and anti-anxiety drugs can combat preoperative anxiety and relieve postoperative pain. Shimony et al.18 concluded that perioperative use of pregabalin could attenuate preoperative anxiety, as well as reduce postoperative pain scores and analgesic usage without increasing the incidence of adverse events. Similarly, preoperative oral gabapentin was effective for reducing not only preoperative anxiety but also postoperative pain and morphine consumption in morbidly obese patients who had undergone laparoscopic sleeve gastrectomy.19 Moreover, other studies have suggested that adults undergoing outpatient dermatologic surgery, dental surgery, and endoscopic procedures benefit from oral midazolam because it is safe and effective for reducing perioperative pain, anxiety, or both.20,21 However, Bayer et al.7 found out that although 10 mg of oral midazolam reduced preprocedural anxiety, it did not reduce pain associated with uterine aspiration during first-trimester surgical abortions. Their experimental design was similar to ours but with somewhat different results, which may be related to the mode and timing of administration.
The mechanism by which preoperative anxiety causes postoperative pain aggravation is still unclear. Wu et al.22,23 revealed that preoperative anxiety could cause hyperalgesia by means of impairing the GABAergic system. In our study, we selected two GABAA receptor agonists—intermediate-acting estazolam and ultra-short-acting remimazolam. Estazolam is a sedative, hypnotic, and anxiolytic drug, which is often used before bed by patients with anxiety. Remimazolam is a novel benzodiazepine with quick onset, short maintenance, short recovery time, no accumulation of metabolism, and no serious side effects, which is suitable for quickly relieving tension for patients before surgery. Remimazolam is now mostly used as an anticonvulsant and an intensive care tranquilizer.24 More clinical trials are needed to determine whether the application of estazolam and remimazolam—in combination or separately—can reduce preoperative anxiety and postoperative pain by acting on GABAA receptors. The drug dosage selection in this study was based on preliminary experimental results. We found that the mean preoperative anxiety scores—determined after patients entered the operating room—of patients who took oral estazolam before bedtime were significantly lower than those of patients who did not take bedtime estazolam. The mean anxiety scores measured 10 minutes after preoperative administration were significantly lower among patients who were given remimazolam than among those who were not. The mean pain scores (VAS) were significantly lower in the combination group at 0.5, 1, 4, 8, 24, 48, and 72 hours after surgery and lower in the estazolam or remimazolam groups at 4, 8, and 24 hours after surgery, compared with the placebo group. The mean cumulative sufentanil consumption was significantly lower in the combination group at 0.5, 1, 4, 8, 24, 48, and 72 hours after surgery and lower in the estazolam or remimazolam group at 0.5 hours after surgery, compared with the placebo group. There was no excessive sedation in the preoperative administration groups. Additionally, anesthesia satisfaction was significantly higher among patients who received estazolam or remimazolam preoperatively.
An important limitation of the study was that it did not take into account patients undergoing emergency gynecological surgery. Also, we only took female (gynecology) patients into consideration. Finally, we only used benzodiazepines in the study. Future studies should extend the inclusion criteria, and the most suitable drug dosage for reducing preoperative anxiety to relieve postoperative pain should be studied thoroughly. Moreover, the effects of other anxiolytic drugs on postsurgical pain should be researched.
In conclusion, preoperative administration of estazolam, remimazolam, and their combination is beneficial in terms of reductions in preoperative anxiety and postoperative pain without excessive sedation for patients undergoing gynecological laparoscopic surgery. Moreover, the preoperative combination can reduce postoperative sufentanil consumption, which further optimizes the clinical effects.