Khanduja 2013.

Methods	RCT, single‐blinded, 2 parallel groups
Participants	Number: 60 men (n = 12) and women (n = 48) Country: India Surgery: laparoscopic cholecystectomy, general anaesthesia, elective ASA: not reported, probably I and II (judged by exclusion criteria) Age: 20 to 65 years Other inclusion criteria: none reported Exclusion criteria: anaemia, long‐term medications or any medication within 1 week before surgery, history of any chronic disease, cardiac problem, history of drug abuse, consumption of more than 30 g alcohol/d, use of β‐blockers and abnormal preoperative electrolyte concentrations
Interventions	Dexmedetomidine 0.5 μg/kg/h intravenous infusion initiated 30 minutes before induction and augmented to 0.6 μg/kg/h after induction of anaesthesia vs Normal saline at the same volume All participants: Premedication: esomeprazole 40 mg the night before surgery Anaesthesia and during surgery: 2 minutes before induction, pentazocine 0.5 mg/kg in control group and 0.3 mg/kg in dexmedetomidine group. Glycopyrrolate 0.2 mg, thiopentone sodium 2 mg/kg plus repeated boluses of 25 mg, succinylcholine hydrochloride (1.5 mg/kg). End‐inspiratory isoflurane 1.2% in the control group and 0.6% in the dexmedetomidine group. Rocuronium 0.8 mg/kg, neostigmine 2.5 mg, glycopyrrolate 0.4 mg. Additional boluses of pentazocine (0.1 mg/kg) were administered on signs of intraoperative pain After surgery: Patients were given an extra dose of pentazocine on complaint of immediate postoperative pain. Nothing else reported
Outcomes	Number of participants with postoperative pain. No time point specified, but probably immediately after extubation
Notes	A significant difference was reported in the total amount of administered pentazocine (mg, mean, SD): 17.9 ± 4.13 in the dexmedetomidine group vs 29.4 ± 4.272 in the placebo group (P value < 0.001), including intraoperative need and predetermined difference in induction dose Duration of study ≥ 30 minutes after surgery, not further specified. Study authors contacted for details of follow‐up, random sequence generation, allocation concealment, etc, without luck
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...randomized..." Comment: not reported how
Allocation concealment (selection bias)	Unclear risk	Nothing reported
Blinding of participants and personnel (performance bias) Pain, 'rescue' analgesia, postoperative sedation	Low risk	Quote: " ...single blinded..." Comment: probably non‐blinded anaesthesiologist assessing all outcomes (time of follow‐up approximately 30 minutes after surgery). This could have influenced the intraoperatively administered amount of pentazocine, which was significantly different between groups. An unblinded anaesthesiologist might have an interest in showing reduced need for intraoperative analgesia/anaesthesia in the intervention group, or he might anticipate that participants would have more pain. Thus, the possible direction of bias would be to underestimate the effect of intervention; therefore the risk of bias was low
Blinding of participants and personnel (performance bias) PONV	Unclear risk	Not relevant
Blinding of participants and personnel (performance bias) Time to first passage of flatus or stool	Unclear risk	Not relevant
Blinding of participants and personnel (performance bias) Time to first out‐of‐bed mobilization	Unclear risk	Not relevant
Blinding of participants and personnel (performance bias) Post‐interventional complications or side effects	Unclear risk	Not relevant
Blinding of outcome assessment (detection bias) Pain, 'rescue' analgesia, postoperative sedation	Low risk	Quote: "...single blinded..." Comment: the same comment as under performance bias
Blinding of outcome assessment (detection bias) PONV	Unclear risk	Not relevant
Blinding of outcome assessment (detection bias) Time to first passage of flatus or stool	Unclear risk	Not relevant
Blinding of outcome assessment (detection bias) Time to first out‐of‐bed mobilization	Unclear risk	Not relevant
Blinding of outcome assessment (detection bias) Post‐interventional complications or side effects	Unclear risk	Not relevant
Incomplete outcome data (attrition bias) All outcomes	Low risk	No incomplete data
Selective reporting (reporting bias)	Unclear risk	Insufficient information to allow a judgement; no protocol available
Other bias	Unclear risk	Insufficient information to allow a clear judgement