Rossi 1976.

Study characteristics
Methods	Parallel design (2 arms) Country: Italy Follow‐up period: 3 weeks
Participants	Randomly assigned: N = 246 Lidocaine group: 40.24% (99/246) Control (physiological solution and intervention in equal volumes) group: 59.7% (147/246) Age, years: not reported Gender, male: not reported Inclusion criteria Age < 70 years Sudden chest pain, started no more than 8 hours earlier, lasted longer than 10 minutes, nitroglycerin‐resistant and not affected by respiratory movements Exclusion criteria Hypotension Bradycardia Arrhythmia that requires immediate treatment
Interventions	Lidocaine by an intramuscular injection of 250 mg Placebo: physiological solution and intervention in equal volumes Co‐intervention: not reported
Outcomes	Mortality Incidence of severe arrhythmias
Notes	Sample size calculation a priori: not reported Sponsor: Astra Company Role of sponsor: Lidocaine and saline solutions have been packaged for the double‐blind by Astra Company Trial conduction dates: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"and was randomised... " (page 221) Insufficient information about the sequence generation process to permit judgement of ‘low risk’ or ‘high risk’
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement of ‘low risk’ or ‘high risk’
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"The contents of the syringe [are] kept secret until after the search. The distribution of the drug or placebo was randomised at the time of the package" (page 221)
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information about the blinding level process to permit judgement of ‘low risk’ or ‘high risk’
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The report gave the impression that no dropouts or withdrawals had occurred, but this was not specifically stated
Selective reporting (reporting bias)	Low risk	All clinically relevant and reasonably expected outcomes were reported
Other bias	High risk	Design bias (Porta 2008) Industry bias