Corrected carotid flow time and passive leg raise as a measure of volume status

Abstract

BackgroundThe aim of this study was to investigate the value of corrected carotid flow time (FTc) with passive leg raise (PLR) as a non-invasive marker of volume status in end stage renal disease (ESRD) patients. MethodsProspective observational study of ESRD patients presenting to the Emergency department requiring hemodialysis. The common carotid artery was evaluated in long axis. Flow time measurements pre- and post-dialysis as well as before and after PLR were recorded. Results54 patients were enrolled, of which, 30 (55%) were male. The mean age was 47.4 years. The mean volume of fluid removed was 3.89 ± 0.91 L. In the pre-dialysis cohort, the mean FTc was 340.16 ms (95% CI, 330.36–349.95). Following PLR, the mean FTc was 341.34 ms (95% CI 331.74–350.94). In the post hemodialysis cohort, the mean FTc was 302.48 ms (95% CI, 293.63–311.32). Following the PLR maneuver, the mean FTc was 340.49 ms (95% CI 331.97–349.02). The mean decrease in corrected carotid flow time was 19.15 ms (95% CI, 22.86–41.17), 32.02 ms (95% CI 4.05–34.25) and 41.17 ms (95% CI, 36.47–54.76) for patients who had <3 L, 3-4 L and >4 L removed, respectively. In patients without CHF, the mean decrease in FTc after hemodialysis was 38.80 ms (95% CI, 30.12–47.49) whereas for CHF patients the mean decrease was 35.60 ms (95% CI, 25.05–46.15). ConclusionCorrected flow time in conjunction with passive leg raise seem to correlate with volume status in hemodialysis patients.