Augmentation of peripheral venous diameter for ultrasound-guided peripheral intravenous line insertion.

OBJECTIVES

Ultrasound-guided intravenous line placement is utilized often in the emergency department for venous access in patients whose veins are difficult to cannulate by traditional methods. This study aims to identify specific interventions that will augment venous cross-sectional area.

METHODS

Residents and medical students volunteers each had their basilic vein identified using the linear array probe on an ultrasound. The area of the vein was measured with no intervention with the arm positioned parallel to the floor as well as approximately 45 degrees below the level of the bed. These two positions were repeated with the following interventions: one standard rubber tourniquet applied proximal to the vein measurement, an additional rubber tourniquet applied proximal to first tourniquet, blood pressure cuff inflated to between 160 and 200 mmHg applied proximal to the vein, CAT battle tourniquet application proximal to measurement site, and soaked warm towel applied to brachium for up to one minute. The primary outcome was to evaluate the increase in venous cross-sectional area from the baseline measurement after the interventions.

RESULTS

We had 41 participants in this study. All interventions were statistically significant in increasing venous cross-sectional area as compared to no intervention, with the most significant augmentation being from the CAT battle tourniquet (mean change +7.32 mm2, 95% CI, 5.73-8.91 mm2) . The change in position of the arm, was not statistically significant for any intervention except for the CAT tourniquet (mean change -1.74 mm2, 95% CI, -0.54 to -2.93 mm2). There was no significant difference between two tourniquets and blood pressure cuff (mean change +0.58 mm2, 95% CI, -1.13 to +2.29 mm2), but there was a significant increase in cross-sectional area with CAT tourniquet use compared to blood pressure cuff (mean change +1.62 mm2, 95% CI, 0.29-2.95 mm2). Lastly, two tourniquets increased cross- sectional area compared to one tourniquet (mean change +2.20 mm2, 95% CI, 1.14 - +3.26 mm2).

CONCLUSIONS

This study identified several potential interventions for maximizing venous cross-sectional area on ultrasound. All the tested interventions resulted in statistically significant increases in cross-sectional area. Arm positioning did not show significant changes in most interventions, with the exception of the CAT tourniquet. Further studies should be performed on how these maneuvers affect success in ultrasound-guided intravenous line placement.