Bahl 2016.

Study characteristics
Methods	Randomised, open‐label trial
Participants	Setting: ED Number of participants: 122 (USG 63, LM 59) Age, mean (SD) years: USG 61 (not specified), LM 62 (not specified) Difficulty: difficult (participants reported past difficulties or experienced at least one previous episode where at least 2 attempts were required to obtain a peripheral IV) Sites of peripheral veins: upper extremity
Interventions	Technique LM vs USG: Machine: Sonosite M‐turbo (Sonosite) with a high‐frequency linear transducer Axis: not specified Guidance: not specified Operator Profession: ED registered nurses Number of operators: 20 Experience of USG before the study: no Length of experience with USG before the study: none A training programme of USG for the study: yes Number of clinical cases with USG required or experienced before the study intervention started: 10 Needle Length: not specified Gauge: not specified
Outcomes	First‐pass success of cannulation, time for overall cannulation, number of attempts Definition of successful cannulation: blood return from a catheter, smooth normal saline flush, and no signs of extravasation Definition of start and end of time measurement Start: a study nurse placed a tourniquet on a participant End: functional intravenous cannulation was obtained and a tegaderm was positioned over the catheter
Funding	Blue Cross Blue Shield of Michigan Physician Investigator Award Number 2069
Declarations of interest	None declared
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The randomisation scheme was created by a biostatistician using a computer‐generated program
Allocation concealment (selection bias)	Low risk	Randomisation with varying block sizes, sealed envelopes
Blinding (performance bias and detection bias) First‐pass success of cannulation	Low risk	Although blinding of participants and operators is impossible due to the nature of the intervention, a third person assessed the outcome (this was not stated in the article, but obtained through the communication with an author (AB))
Blinding (performance bias and detection bias) Overall‐success of cannulation	Low risk	Although blinding of participants and operators is impossible due to the nature of the intervention, a third person assessed the outcome (this was not stated in the article, but obtained through the communication with an author (AB))
Blinding (performance bias and detection bias) Procedure time for overall cannulation	Low risk	Although blinding of participants and operators is impossible due to the nature of the intervention, a third person assessed the outcome (this was not stated in the article, but obtained through the communication with an author (AB))
Blinding (performance bias and detection bias) Number of attempts	Low risk	Although blinding of participants and operators is impossible due to the nature of the intervention, a third person assessed the outcome (this was not stated in the article, but obtained through the communication with an author (AB))
Incomplete outcome data (attrition bias) First‐pass success of cannulation	Low risk	The outcome was available for all participants
Incomplete outcome data (attrition bias) Overall success of cannulation	Low risk	The outcome was available for all participants
Incomplete outcome data (attrition bias) Procedure time for overall cannulation	Low risk	The outcome was available for all participants
Incomplete outcome data (attrition bias) Number of attempts	Low risk	The outcome was available for all participants
Selective reporting (reporting bias)	Unclear risk	No study register or protocol was available
Other bias	Low risk	No concerns about other sources of bias
Overall risk First‐pass success of cannulation	Unclear risk	At least one domain was unclear
Overall risk Overall success of cannulation	Unclear risk	At least one domain was unclear
Overall risk Procedure time for overall cannulation	Unclear risk	At least one domain was unclear
Overall risk Number of attempts	Unclear risk	At least one domain was unclear