Krobbuaban 2008.

Methods	Double‐blind randomized controlled trial
Participants	Age (years, mean ± SD): Group I = 43 ± 17, Group II = 44 ± 16 Gender (M:F): Group I = 62:73, Group II = 66:67 Inclusion criteria: age 18 years to 60 years, ASA I or II, and undergoing an elective surgical procedure with general anaesthesia Exclusion criteria: patients with a neurological or cardiovascular disorder, history of drug abuse, or egg lecithin or soybean oil allergies, as well as patients breast feeding at the time of surgery, taking sedatives or analgesics within 24 hrs preceding surgery or requesting anxiolysis Recruitment: 270 adult patients randomly assigned (268 were analysed) Setting: Thailand
Interventions	Admixture Patients were allocated randomly into two groups to receive either propofol‐MCT/LCT alone (n = 135) or propofol‐MCT/LCT plus 20 mg lidocaine admixture (n = 133) The study solution was injected at 1 ml/second by one anaesthesiologist and patients graded any associated pain
Outcomes	Pain intensity assessed on 4‐point scale 0 = no pain 1 = mild pain (pain in response to questioning only without any behavioural signs) 2 = moderate pain (pain in response to questioning and accompanied by behavioural sign or pain reported spontaneously without questioning) 3 = severe pain (strong vocal response or response accompanied by facial grimacing, arm withdrawal, or tears) Outcomes reported and used Incidence of high‐intensity pain Incidence of pain Adverse effects Outcomes sought but not reported Patient satisfaction
Notes	Period of the study: dates not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Using computer‐generated random numbers
Allocation concealment (selection bias)	Unclear risk	N/A
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"As the physical appearances of the two study drugs were identical, the anaesthesia providers and an investigator recording were unaware of the propofol formulation. The propofol solutions were prepared by a nurse anaesthetist in unlabeled syringes as per the patient’s group allocation."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"As the physical appearances of the two study drugs were identical, the anaesthesia providers and an investigator recording were unaware of the propofol formulation."
Incomplete outcome data (attrition bias) All outcomes	Low risk	"Two patients from the propofol‐MLC/LCT plus lidocaine group were excluded from the analysis due to protocol violation (midazolam given before induction)."
Selective reporting (reporting bias)	Unclear risk	N/A
Other bias	Low risk	The study was financially supported by Chaiyaphum (government) Hospital. The study appears to be free of other sources of bias