This study was designed to evaluate the effects of two anesthesia regimens on postoperative recovery in patients undergoing laparoscopic bariatric surgery. A sample size of 60 patients was chosen based on preliminary power analysis, which indicated that this number would provide sufficient power (80%) to detect a clinically significant difference in recovery quality between the two groups, assuming a medium effect size and a significance level (alpha) of 0.05. This sample size was selected to ensure the study could differentiate between the effects of the two anesthesia regimens and to minimize the risk of the study being underpowered.

Patients diagnosed with obesity undergoing bariatric surgery in our hospital were selected based on the following inclusion criteria: (1) the patients were aged 18–65 years; (2) the patients with a BMI ≥35 kg/m² met the indications for bariatric surgery; (3) the patients of the American Society of Anesthesiologist (ASA) physical status were II–III (17); and (4) the patient participated in the trial voluntarily and signed the informed consent form. The exclusion criteria included: (1) preoperative liver and renal dysfunction; (2) preoperative presence of chronic pain and long-term use of opioid painkillers; (3) congenital heart disease, arrhythmia, or hypertension; (4) allergy to the drugs used in the trial; and (5) presence of contraindications to laparoscopic surgery. The study complied with the Declaration of Helsinki and was approved by the Ethics Committee of The Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine.

In this study, the patients were divided into the Sev + Rem group and the Pro + Rem group based on the treatments they underwent. Patients in both groups underwent laparoscopic bariatric surgery, including gastric sleeve and Roux-en-y gastric bypass. All patients were informed to fast for 8 h and deprived of water for 4 h prior to surgery. Before anesthesia, venous access to the upper extremities was obtained, electrocardiogram monitoring and depth of anesthesia monitoring were connected, and oxygen masks were provided. The patients in the Sev + Rem group were induced with sevoflurane, starting at a concentration of 0.5% and gradually increasing by 0.5–4% with each breath. With the increase in the number of breaths, the concentration gradually increased by 0.5–4% (18). The concentration was elevated every 2–3 breaths. Besides, the oxygen flow was set to 4 L/min. Rocuronium bromide (0.8 mg/kg) was administered intravenously after loss of consciousness, and the patients were mechanically ventilated by tracheal intubation with a tidal volume of 10 mL/kg. Remifentanil (4.0 ng/mL at the site of action) was injected continuously, and sevoflurane inhalation was maintained. The patients in the Pro + Rem group were given propofol at 4–8 mg/(kg·h) and a target-controlled infusion of remifentanil was administered, with the blood drug concentration at 3 ng/mL (18, 19). Anesthesia was stopped after surgery. During surgery, norepinephrine was administered to manage hypotension. It was diluted in a standard solution of 0.1 mg/mL and titrated to maintain mean arterial pressure (MAP) within 65–75 mmHg. The dosing was adjusted based on the hemodynamic response of each patient, with continuous monitoring to ensure safety and efficacy. The depth of anesthesia in all patients was determined using the bispectral index (BIS), of which the BIS was maintained at 40–60.

Perioperative data of patients were collected, including baseline data such as age, sex, weight, height, BMI, ASA class (II/III), smoking history (yes/no), alcohol abuse history (yes/no); and intraoperative and postoperative data such as surgical method, remifentanil dose, vasoactive drugs use, blood loss, duration of anesthesia, operation time, extubation time, post-anesthesia care unit (PACU) length of stay, onset time of postoperative off-bed activity, time of first postoperative defecation, and hospitalization time.

Mean arterial pressure (MAP) and heart rate (HR) were measured before the induction of anesthesia (T1), after the induction of anesthesia (T2), at the beginning of surgery (T3), 1 h after surgery (T4), and at the end of surgery (T5).

In this study, the quality of recovery-40 (QoR-40) questionnaire was used to assess the quality of recovery of patients in both groups at 24 h after surgery. The QoR-40 questionnaire measures 40 items in five dimensions: physical comfort, physical independence, emotional state, psychological support, and pain. Each item is scored from 1 to 5, with a total score of 200 (optimal quality) (20).

The adverse reactions such as nausea, vomiting, post-extubation dyspnea, fever and chills, hypoxemia, and bradycardia were recorded from the end of anesthesia to the end of awakening.

The study’s primary endpoint was the quality of recovery, assessed using the QoR-40 questionnaire at 24 h post-surgery, focusing on physical comfort, physical independence, emotional state, psychological support, and pain. Secondary endpoints included intraoperative and postoperative metrics (surgical method, remifentanil dose, vasoactive drug use, blood loss, duration of anesthesia, operation time, extubation time, PACU length of stay, onset time of postoperative off-bed activity, time of first postoperative defecation, and hospitalization time). Additionally, hemodynamic measurements, including heart rate and mean arterial pressure, were recorded at five time points (before induction of anesthesia, after induction, at the beginning of surgery, 1 h after surgery, and at the end of surgery). The incidence of anesthesia-related adverse reactions, such as nausea, vomiting, post-extubation dyspnea, fever and chills, hypoxemia, and bradycardia, were also monitored from the end of anesthesia to the end of awakening. These endpoints aimed to compare the effects of sevoflurane vs. propofol, both combined with remifentanil, on postoperative recovery quality and various perioperative parameters in patients undergoing laparoscopic bariatric surgery.

Measurements data of normal distribution were expressed as mean ± standard deviation. Independent samples t-test was used to compare the means between the two groups. Enumeration data were represented as percentages and rates, and the chi-square was used to compare the groups. For all statistical comparisons, p < 0.05 was considered statistical significance. Statistical analysis and plotting were performed using GraphPad Prism 8.0.

A total of 60 patients were included in this study, including 33 males and 27 females. The mean age of patients in the Sev + Rem group was 48.53 ± 8.03 years old, with 18 males and 12 females; the mean age of patients in the Pro + Rem group was 49.57 ± 6.31 years old, with 15 males and 15 females. Notably, there was no statistical difference in age and sex ratio between the two groups and also no statistically significant difference in height (1.71 ± 0.08 vs. 1.71 ± 0.09 m), weight (108.3 ± 12.18 vs. 108.73 ± 12.19 kg), BMI (37.09 ± 1.64 vs. 36.88 ± 1.18 kg/m²), ASA class, and previous history of smoking and alcohol in the below groups (Table 1).

There was no statistical difference in the choice of surgical methods between the two groups. In terms of anesthetic drug use, the dose of remifentanil in the Sev + Rem group (1693.67 ± 331.75 μg) was significantly lower than that in the Pro + Rem group (2,959 ± 359.77 μg) (p < 0.001). No significant difference in the use of remaining vasoactive drugs was seen between the two groups, except for the higher use of norepinephrine in the Sev + Rem group [16 (53.33) vs. 8 (26.67), p = 0.035]. In terms of postoperative monitoring, the time of tracheal extubation was earlier in the Sev + Rem group compared to the Pro + Rem group (356.33 ± 63.17 vs. 400.3 ± 50.11, p = 0.004). There was no significant difference between the two groups in intraoperative blood loss, duration of anesthesia, operative time, PACU length of stay, onset time of postoperative off-bed activity, time of first postoperative exhaust and defecation, and hospitalization time (Table 2).

The hemodynamics of the patients were monitored before T1, T2, T3, T4, and T5. This study revealed that the HR of the two groups showed a downward trend after T1; the HR was markedly lower in the Pro + Rem group in comparison with the Sev + Rem group at T3 and T4 (67.37 ± 4.40 vs. 64.33 ± 4.44, p = 0.010); and the HR was almost the same in both groups at T5. The MAP in the Pro + Rem group dropped slightly as opposed to the Sev + Rem group after T2. Notably, no statistically significant difference was observed in MAP between the two groups at each time point (Table 3).

After evaluating the QoR-40 questionnaire in the two groups at 24 h after surgery, the study suggested that the score of postoperative emotional state in the Pro + Rem group was higher than that in the Sev + Rem group (39.50 ± 4.64 vs. 36.83 ± 2.79, p = 0.009). Besides, the difference was not statistically significant between the two groups in the remaining aspects of the assessment. The total scores of QoR-40 questionnaires in the Sev + Rem group and the Pro + Rem group were almost the same, indicating that there was no significant difference in the postoperative quality of recovery between the two groups (Table 4).

The common adverse reactions of patients after anesthesia were recorded to investigate the effects of different anesthesia modalities on the postoperative anesthesia-related adverse reactions of patients. As shown in Table 5, nausea was the most common adverse reaction after anesthesia in this study, with a total incidence of 63.33%, while the incidence of fever and chills was the lowest, both 5%. However, different anesthesia modalities did not affect the incidence of postoperative anesthesia-related adverse reactions in patients, and no statistically significant difference was found in adverse reactions between the two groups.