Arm position and collapsibility of infraclavicular axillary vein during voluntary breathing: An ultrasound-guided observational study.

Background: Arm abduction influences cross-sectional area of the infraclavicular axillary vein, yet the effect of arm abduction on collapsibility of the vein has not been quantified. Decrease in collapsibility of the axillary vein can enable successful cannulation and can decrease injury to underlying vital structures.

Methods: The infraclavicular axillary vein was scanned in 70 patients close to the clavicle with a high-frequency linear transducer in arm adducted position (Point A), after arm abduction at the initial probe position (Point A') and after tracing the vein medially close to clavicle (Point B). Maximum and minimum cross-sectional area and circumference during tidal breathing and collapsibility indices during tidal and deep breathing were measured at three probe positions.

Results: The percentage change with respiration in cross-sectional area, circumference and the collapsibility indices computed from the above measurements were lesser in arm abducted position (p < 0.001). There was decrease in collapsibility index during tidal breathing from 25 at Point A to 7 at Point A' and 3 at Point B. Collapsibility index reduced from 91 at Point A to 30 at Point A' and 35 at Point B during deep breathing.

Conclusion: We conclude that the collapsibility of the infraclavicular axillary vein could be reduced by arm abduction, and hence, abduction could be proposed as the ideal arm position for ultrasound-guided infraclavicular axillary vein cannulation.