McKay 2009.

Methods	Randomized, placebo‐controlled trial. No statement on allocation concealment. No statement on blinding of participants, personnel, and outcome assessors. This trial evaluated whether systemic lidocaine would reduce pain and time to discharge in ambulatory surgery patients. The study was conducted in the USA from August 2004 to August 2006.
Participants	Number assessed for eligibility: N/A Number randomized: 67 → N/A Number analysed: 29:27 Inclusion criteria Patients 18 to 75 yrs of age (ASA physical status I to III) presenting for outpatient surgery under general anaesthesia. Exclusion criteria N/A Baseline details Experimental group (n = 29) Mean age (years): 43 M = 83%, F = 17% Mean weight (kg): 81 ASA I/II: N/A Duration of anaesthesia (min): N/A Main surgical procedure (n): laparoscopic general (11), open general (3), endocrine and breast (7), laparoscopic gynaecology (4), minor gynaecology (2), urology (0), plastics (2), minor ortho (0), minor ear, nose, throat (0) Control group (n = 27) Mean age (years): 46 M = 78%, F = 22% Mean weight (kg): 81 ASA I/II: N/A Duration of anaesthesia (min): N/A Main surgical procedure (n): laparoscopic general (13), open general (3), endocrine and breast (5), laparoscopic gynaecology (2), minor gynaecology (0), urology (1), plastics (1), minor ortho (1), minor ear, nose, throat (1)
Interventions	Experimental group (29 patients) At induction of anaesthesia, all patients received 1.5 mg/kg of lidocaine by slow IV push. The lidocaine infusion (2 mg/kg/hr) was started immediately after induction of anaesthesia and continued until 1 hr after arrival in the PACU. Control group (27 patients) The control group received saline as placebo.
Outcomes	The primary endpoint of the study was time to PACU discharge readiness. Dichotomous Postoperative nausea and vomiting during 24 hrs after surgery Side effects (dizziness, visual disturbance) Continuous Length of PACU stay Pain score (VAS 0 to 10) at rest during PACU every 15 min up to 165 min (data presented graphically), total pain during PACU and 24 hrs after discharge Morphine consumption (mg), intraoperatively, PACU, 24 hrs after discharge, 0 to 24 hrs
Notes	Small trial sample size (< 200 patients) Power analysis performed (time to PACU discharge readiness, n = 25) Medication "Pain was assessed at rest by a visual analogue scale every 15 min and treated with either fentanyl (0.5 – 1 µg/kg) or morphine (0.01 – 0.02 mg/kg) when pain was more than 3 on a visual analogue scale of 0–10 (0 = no pain, 10 = more pain imaginable). Nausea was assessed at 15‐min intervals and treated with ondansetron or if persistent with promethazine or diphenhydramine." Anaesthesia Anaesthetic management during surgery was standardized for opioid use, ketorolac and prophylaxis for postoperative nausea and/or vomiting. Funding "Supported by departmental funding."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "participants were assigned in a double‐blind 1:1 ratio using a computer‐generated randomization list…"
Allocation concealment (selection bias)	Unclear risk	No statement on allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "…double‐blind…". No detailed information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No statement on blinding of outcome assessors.
Incomplete outcome data (attrition bias) All outcomes	High risk	Dropout rate overall: 16% Quote: "based on an expected withdrawal rate of 20%, 67 patients were enrolled in the trial." Only 56 were analysed, 11 excluded. Excluded patients were not described.
Selective reporting (reporting bias)	Unclear risk	There is no reference to a trial registry and no published study protocol.
Other bias	Low risk	The study appears to be free of other sources of bias.