Effect of respiration on the spectral Doppler wave of the right hepatic vein in right lobe living donor liver transplant recipients

Objective. The purpose of this study was to evaluate the effect of respiration on the spectral Doppler wave of the right hepatic vein (RHV) in right lobe living donor liver transplant (L DLT). recipients. Methods. A spectral Doppler wave of the RHV was obtained from 23 consecutive right lobe LDLT recipients who had no complications and from 2 healthy subjects during free breathing, breath holding at expiration, and breath holding at inspiration. To assess the RHV flow quantitatively, the venous periodicity index (VPI) was calculated as follows: VPI = (V-F -V-R)/V-F,where V-F was the measured peak forward velocity, and V-R was the measured peak reversed velocity. The mean VPIs of the RHV obtained in the 3 respiratory states were compared by repeated measures analysis of variance. Spectral Doppler waves of the RHV were categorized as triphasic with or without reversed flow, biphasic, or monophasic and were compared among the 3 respiratory states. Results. In both right lobe LDLT recipients and healthy subjects, the mean VPIs of the RHV obtained during breath holding at inspiration were significantly lower than those during free breathing (P <.001) and breath holding at expiration (P <.001). The wave pattern during breath holding at inspiration was monophasic in 7 (30.4%) right lobe LDLT recipients and 3 (11.5%) healthy subjects, whereas the monophasic pattern was not seen during free breathing or breath holding at expiration in any of these subjects. Conclusions. Breath holding at inspiration significantly reduces the periodicity of RHV flow and can make otherwise pulsatile RHV flow monophasic in right lobe LDLT recipients without postoperative complications as well as in healthy individuals.