Do Respiratory Maneuvers Affect Rght Hepatic Vein Waveform and Maximum Velocity in Post LDLT Recipients?
Keywords:Respiratory, Maneuvers, Hepatic, Vein, Waveform, Liver
AIM: Â To evaluate the effect of respiratory maneuvers on right hepatic vein (RHV) Doppler waveform and its maximum velocity in Living donor liver transplant (LDLT) recipients.
METHODS: This was a prospective cross-sectional study performed at Pakistan Kidney and Liver Institute and Research Centre (PKLI& RC), Lahore Radiology department. The sample size of the study, calculated according to WHO sample size calculator, was 30 patients after applying the inclusion and exclusion criteria. Most of these patients were analyzed during their first post-operative week while staying in the surgical intensive care unit (SICU). The Doppler waveform and maximum velocity of RHV were recorded during normal gentle breathing, following breath-hold after deep inspiration and then after quiet expiration. The waveforms that were recorded were triphasic, biphasic, or monophasic in the pattern. To assess the RHV flow quantitatively, the Damping Index was also calculated during all these three respiratory maneuvers as follows (DI=Minimum velocity/maximum velocity)
RESULTS: The maximum velocities during normal respiration, after quiet expiration and after breath-holding following deep inspiration were 125 cm/sec, 105 cm/sec and 94 cm/sec. The waveforms observed during gentle breathing were triphasic in 77%, biphasic in 10%, and monophasic in 13% of the patients. After quiet expiration, these were triphasic in 80%, biphasic in 6%, and monophasic in 13% of patients. However, after breath-hold following deep inspiration, the waveforms observed were triphasic in 42%, biphasic in 13%, and monophasic in 45% of the patients. (P <0.008)
CONCLUSION: The study showed that not only did the RHV waveforms show significant change from triphasic pattern to monophasic pattern, but also the peak velocities were lower following expiration. Therefore, during the Doppler ultrasound assessment of post-LDLT recipient patients, respiratory variations must be taken into consideration.
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