This prospective randomized study was conducted after obtaining approval from institutional research ethical committee (GCSMC/EC/Research project/APPROVE/2021/264). The clinical trial registration was done before the start of the study (CTRI/2021/10/037206). All the principles of the Helsinki Declaration were followed during the study course. After taking patient’s written informed consents, this double-blind study included total of 100 patients. Randomization was done by computer-generated system, and those giving the drug as well as those receiving the drug were unaware about the exact drug. All patients were randomly allocated to one of the two equal groups (50 patients each) using a computer-generated table of randomization. The list was concealed in sealed envelopes that were numbered and opened sequentially after obtaining patient’s consent. Group RD patients received intraperitoneal 0.2% ropivacaine 30 ml plus 8 mg dexamethasone (total 32 ml), and group RS received intraperitoneal 0.2% ropivacaine 30 ml plus 2 ml normal saline (total 32 ml) (Fig. 1).

All patients were evaluated at preoperative anesthesia clinic. The NRS pain scale was explained to the patients during preoperative checkup. The inclusion criteria included the patients who were posted for elective laparoscopic cholecystectomy under general anesthesia, able to interpret the NRS score with an American Society of Anesthesiology (ASA) physical status I and II, aged 18–70 years of either gender with body mass index (BMI) 18–30 kg m−2, and duration of surgery up to 2 h. Patients with allergy or contraindicated to study drugs, BMI > 30 kgm−2, who are pregnant, who have hepatobiliary malignancies, who have laparoscopy converted to open cholecystectomy, and who have presence of acute cholecystitis, choledocholithiasis, portal hypertension, or compromised systemic illness were excluded from study.

Standard monitors were applied in the operative room, and an intravenous line was secured with 18G intracath. All patients of both groups received general anesthesia. Premedication drug injection of glycopyrrolate 0.2 mg, injection of ondansetron 8 mg, intravenous antibiotic, and injection of fentanyl 100 mcg were given. Patients were induced with injection of propofol 2 mg/kg and injection of suxamethonium 2 mg/kg. Intraoperative maintenance was done with O2, air, and sevoflurane. For muscle relaxation, injection of atracurium 0.5 mg/kg blous followed by maintenance 0.1mg/kg was used. Injection of paracetamol 1 gm was given intraoperatively.

Study drugs were prepared by an anesthesiologist not involved in the study. The anesthesiologist who observed the patient was unaware of the study drug. After completion of the surgery, group RD received injection of ropivacaine (0.2%) 30 ml with injection of dexamethasone (8 mg) 2 ml, while group RS received injection of ropivacaine (0.2%) 30 ml with injection of NS 2 ml total volume 32 ml instilled via trocar in the gallbladder fossa in Trendelenburg position, and this position was kept for 5 min. After that, all trocars were removed, and extubation was done.

In the postoperative room, patients were assessed for pain using the NRS score at rest and at movement. There were complaints of nausea and vomiting at 0 h, 2 h, 4 h, 6 h, 12 h and 24 h, postoperatively. Rescue analgesic injection of diclofenac 75 mg intravenously was given if NRS > 4. Injection of ondansetron 8 mg intravenous was given for > 1 episode of vomiting.

The sample size was calculated using a software (Clincalc.com/stats/samplesize.aspx). In a previous study of Sarvestani et al. (2013), the total VAS score was 10.95 versus 12.95 in intraperitoneal hydrocortisone versus placebo; in reference to this, with 80% power and an alpha of 0.05, a minimum sample of 42 cases was required in each group. We decided to recruit 50 patients in each group.

Statistical analysis was conducted using GraphPad prism/QuickCalcs. The unpaired t-test and chi-square test were used to analyze the continuous and non-parametric data respectively. P < 0.05 was considered statistically significant.