Jeon 2012.

Methods	Double‐blind randomized controlled trial
Participants	Age (years, mean ± SD): Group 1 = 48 ± 14.5, Group 2 = 50 ± 13.5, Group 3 = 45 ± 14.5 Gender (M:F): Group 1 = 13:17, Group 2 = 14:16, Group 3 = 14:16 Inclusion criteria: Age 19 years to 60 years old, ASA I‐II, elective plastic surgery Exclusion criteria: patients with cardiovascular, hepatic, or renal problems; patients who had received analgesic or sedative medications within 24 hours before the surgery; patients with neurological deficits or psychiatric disorders; and patients requiring a rapid sequence induction Recruitment: 90 adult patients randomly assigned (30 in each group) Setting: Korea
Interventions	Pretreatment with venous occlusion Patients were allocated randomly to three groups, to receive lidocaine 20 mg, Group 1 (n = 30), a combination of lidocaine 20 mg and nitroglycerin 0.1 lg/kg Group 2 (n = 30), normal saline as a placebo Group 3 (n = 30), with venous occlusion for 1 min followed by the administration of 25 % of the total calculated dose of propofol (2 mg/kg) into a dorsal hand vein
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 Outcomes reported but not used Haemodynamic variables – mean arterial pressure and heart rate – were measured during the preoperative and intraoperative periods.
Notes	Period of the study: dates not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	N/A
Allocation concealment (selection bias)	Low risk	a sealed envelope technique
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"An anaesthesiologist not involved in this study prepared identically coded syringes."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"Blinded investigator for any complications such as pain, edema, or a wheal and flare response."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals
Selective reporting (reporting bias)	Unclear risk	N/A
Other bias	Low risk	This research was supported by Kyungpook National University Research Fund, 2010. The study appears to be free of other sources of bias