Can emergency physicians perform common carotid Doppler flow measurements to assess volume responsiveness?

Common carotid flow measurements may be clinically useful to determine volume responsiveness. The objective of this study was to assess the ability of emergency physicians (EP) to obtain sonographic images and measurements of the common carotid artery velocity time integral (VTi) for potential use in assessing volume responsiveness in the clinical setting.

In this prospective observational study, we showed a five-minute instructional video demonstrating a technique to obtain common carotid ultrasound images and measure the common carotid VTi to emergency medicine (EM) residents. Participants were then asked to image the common carotid artery and obtain VTi measurements. Expert sonographers observed participants imaging in real time and recorded their performance on nine performance measures. An expert sonographer graded image quality. Participants were timed and answered questions regarding ease of examination and their confidence in obtaining the images.

A total of 30 EM residents participated in this study and each performed the examination twice. Average time required to complete one examination was 2.9 minutes (95% CI [2.4-3.4 min]). Participants successfully completed all performance measures greater than 75% of the time, with the exception of obtaining measurements during systole, which was completed in 65% of examinations. Median resident overall confidence in accurately performing carotid VTi measurements was 3 (on a scale of 1 [not confident] to 5 [confident]).

EM residents at our institution learned the technique for obtaining common carotid artery Doppler flow measurements after viewing a brief instructional video. When assessed at performing this examination, they completed several performance measures with greater than 75% success. No differences were found between novice and experienced groups.