Lauwick 2008.

Methods	Randomized, controlled trial. No statement on blinding of participants. The anaesthesiologists were unblinded. The outcome assessors were blinded. The purpose of this study was to determine whether intraoperative lidocaine infusion reduces opioid consumption in the PACU in patients undergoing laparoscopic cholecystectomy. The study was conducted in Canada from May 2007 to February 2008.
Participants	Number assessed for eligibility: 63 Number randomized: 50 → 25:25 Number analysed: 25:24 Inclusion criteria Outpatient laparoscopic cholecystectomy. Exclusion criteria: Age < 18 yrs or > 85 yrs, ASA physical status III and greater, history of hepatic, renal or cardiac failure, organ transplant, diabetes, morbid obesity (BMI > 40 kg/m2), chronic use of opioids, allergy to local anaesthetics, or inability to comprehend pain assessment. Baseline details Experimental group (n = 25) Mean age (years): 50.2 M = 20%, F = 80% Mean weight (kg): 66.9 ASA I/II: 17:8 Duration of surgery (min): 60 Main surgical procedure: laparoscopic cholecystectomy Control group (n = 24) Mean age (years): 53.8 M = 48%, F = 52% Mean weight (kg): 75 ASA I/II: 11:14 Duration of surgery (min): 70 Main surgical procedure: laparoscopic cholecystectomy
Interventions	Experimental group (25 patients) At induction of anaesthesia the lidocaine group received fentanyl 1.5 µg/kg and a bolus of lidocaine 1.5 mg/kg followed by a continuous infusion of lidocaine 2 mg/kg/hr until the end of surgery. Control group (24 patients) At induction of anaesthesia the control group received fentanyl 3 µg/kg.
Outcomes	The primary endpoint of the study was fentanyl consumption. Dichotomous Postoperative nausea and vomiting during PACU and 24 hrs after surgery Use of ondansetron and number of patients requiring ondansetron (0:2:4:8 mg) Number of patients with White‐Song score > 12 at 1st: 30th: 60th min Continuous Pain score (VRS 0 to 10) during rest at 1 min, 30 min, 60 min, and 90 min, as well as pain score during rest, coughing, walking at 24 hrs (data presented as median with IQR, in part with asymmetric distribution) Shoulder pain (VRS 0 to 10) at 24 hrs (data presented as median with IQR) Fatigue (VRS 0 to 10) at 24 hrs (data presented as median with IQR) White‐Song score at 1 min, 30 min, 60 min, and 90 min (data presented as median with IQR) Fentanyl consumption (µg), intraoperatively and at PACU Time from arrival PACU to discharge home (min), (data presented as median with IQR) Acetaminophen consumption (mg) in 24 hrs Naproxen consumption (mg) in 24 hrs Oxycodone consumption (mg) in 24 hrs
Notes	Small trial sample size (< 200 patients) Power analysis performed (fentanyl consumption, n = 25) Medication "No supplemental opioids were given during surgery. All patients received acetaminophen, ketorolac, dexamethasone, droperidol and local anaesthetics in the skin incision. Patients received fentanyl and ondansetron in the PACU. Before induction of anaesthesia, patients in the control group received fentanyl 3.0 µg/kg iv, while patients in the lidocaine group received fentanyl 1.5 µg/kg iv. No supplemental fentanyl was given to patients in either group during maintenance of anaesthesia. Ketorolac 15 mg and droperidol 0.625 mg were also given intravenously. Ten millilitres of bupivacaine 0.25% with epinephrine was injected into the surgical incisions. According to study protocol, the PACU nursing staff administered fentanyl 25 µg iv boluses for postoperative pain relief, to be administered every five minutes up to a maximum of 200 µg/hr only if the VRS score for pain (0–10 scale, where 0 = no pain, and 10 = excruciating pain) was > 3, at rest. Ondansetron 2 mg iv was prescribed for persistent nausea (lasting > five minutes) or vomiting, and it could be repeated up to four times over a three‐hour period if necessary." Anaesthesia The anaesthesia regime was not fully standardized. The control group received more fentanyl. Funding "This work was supported by internal funds, Department of Anesthesia, McGill University Health Centre."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "...randomly assigned, using a computer‐generated randomization schedule, into two groups of 25 patients…"
Allocation concealment (selection bias)	Low risk	Quote: "...sequentially numbered sealed brown envelopes…"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	The anaesthesiologist was not blinded, but (quote:) "the anaesthesia record was not made available to the recovery room nurse, to avoid bias.", "...the anaesthesiologists (S.L. and F.C.) who executed the study protocol, were not involved in either the preoperative or the postoperative data collection."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "...monitored and recorded by nurses who were blinded to the randomization sequence."; "The anaesthesia record was not made available to the recovery room nurse, to avoid bias."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Dropout rate (experimental/control): 0%:4% Quote: "One patient in the control group was excluded from the analysis because his surgery was converted from laparoscopy to laparotomy."
Selective reporting (reporting bias)	Unclear risk	There is no reference to a trial registry and no published study protocol.
Other bias	Unclear risk	The study groups differ with a greater proportion of males (48% versus 20%) in the control group.