Khan 2018.

Study characteristics
Methods	[Abstract of event] Single‐centre prospective randomised controlled 2‐arm parallel‐assignment open‐label study India Duration: not reported
Participants	100 participants randomised, (experimental = 49, comparator = 51) 100 participants analysed mean age (years) ± SD: not reported gender (male/female): not reported severity of condition (experimental/comparator): critically ill participants comorbidities (experimental/comparator): not reported body weight (kg): not reported height (cm): not reported artery of interest: radial diameter (mm), mean ± SD: not reported catheterisation purpose (experimental/comparator): all for diagnosis (not detailed) Inclusion criteria aged > 18 years hypotension (or requiring vasopressor infusion) no previously cannulated radial artery Exclusion criteria deformity or local trauma or local infection at arterial cannulation site severe coagulopathy (platelets < 30,000/mm³ and/or INR > 2.0) non‐palpable radial pulse radial artery already cannulated previously negative Barbeau test
Interventions	Experimental: ultrasound‐guided RA puncture (real‐time; artery short axis; needle in out‐of‐plane) Comparator: RA puncture via palpation and landmarks Level of experience of person carrying out the procedure: not reported Concomitant medications: not reported Excluded medications: not reported
Outcomes	Primary (specified) first‐pass success rate Primary (collected) first‐pass success rate Secondary (specified) final success rate total number of attempts needed for catheterisation time for successful catheterization (cannulation time) total time taken in the procedure failure rate number of catheters used posterior wall haemorrhage haematoma incidence of spasm and other complications cross‐over to either technique Secondary (collected) cannulation time rate of early complications Time points reported: up to the end of the procedure
Notes	Funding: not reported Conflicts of interest: not reported Protocol (CTRI/2017/03/008020) available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "computer generated randomization"
Allocation concealment (selection bias)	High risk	Quote: "an open list of random numbers"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label study
Blinding of outcome assessment (detection bias) All outcomes	High risk	Open‐label study
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	There were no losses. The account of cross‐over to either intervention was planned but was not reported
Selective reporting (reporting bias)	High risk	Some data (final success rate, time for successful catheterisation (cannulation time), posterior wall haemorrhage, haematoma, incidence of spasm and other complications, cross‐over to either technique) of interest for this review were planned in the trial protocol but were not reported or were reported incompletely (cannulation time)
Other bias	Low risk	We do not suspect any other bias related to this study