Objective: To determine whether sterile saline as a conduction agent provides adequate visualization of anatomic structures to attempt ultrasound-guided vascular access.
Methods: This prospective study involved a convenience sample of adult patients (18 years and older) who presented to an urban academic ED during a 3-month study period. Each patient had three six-second ultrasound video clips obtained of the right internal jugular vein and surrounding structures utilizing three different conduction agents, water-based gel (the control), sterile saline or no conduction agent. Video clips were randomized and assigned a numeric code to blind reviewers to the conduction agent. They were then independently reviewed by two experts who determined whether anatomic structures were visualized with enough detail to perform ultrasound-guided vascular access. The reviewers also rated the overall image quality of each video clip using a 100 mm visual analogue scale (VAS).
Results: Forty-seven patients were included in the final analysis. The raw agreement was 100% (95% confidence intervals [CI]: 93-100%) with a kappa of 1.0 between the two reviewers in assessing whether they would be able to perform vascular access using the images obtained using saline as a conduction agent. The median VAS for gel across both reviewers was 92 (95% CI: 90-93) and the median VAS differences for saline and no medium were -3 (95% CI: -1 to -3) and -46 (95% CI: -22 to -61), respectively.
Conclusions: The use of sterile saline as a conduction agent allows adequate visualization of anatomic structures to attempt ultrasound-guided vascular access.