engleski

Ultrasound Investigation of Ventilatory Effect on Inferior Caval Vein Diameter and Hepatic Viens

In this prospective study, the effect of forced respiration on changes in configuration and hemodynamics of inferior caval vein was investigated in 49 normal subjects and 30 patients with congestive heart failure. The sonographic technique was employed with the aim of standardizing inferior caval vein imaging and finding objective parameters of physiologic and pathophysiologic reaction to alteration in breathing mechanics. Simultaneous employment of B and M mode in subcostal and epigastric probe position provided satisfactory images of inferior caval vein that enabled reliable measurement of its diameter changes. The ICV diameter changes during standardized voluntary maximal inspiration (Mueller maneuver) and voluntary maximal expiration (Valsalva maneuver) may be considered objective indicators of central venous system volume changes, due to its high compliance and unicameral system, whereas ICV has a cylindrical structure. In normal subjects, the largest diameter was recorded at the end of quiet expiration, with the smallest individual variations regarding body surface area. The mean value was 7.5 ± 3.3 mm/m2. In normal subjects, ICV collapse occurred in maximal inspiration, while in maximal expiration the vein lumen extension occurred. The collapse index exceeded 0.3 in these subjects. The patients with congestive heart failure and elevated central venous pressure had markedly larger ICV diameter (18 ± 7 mm). The collapse index highly correlated with CVP. Results of the study suggested the following conclusion: 1. ICV sonography in normal breathing and after standardized imaging technique of Mueller and Valsalva maneuver is a simple and useful procedure ; 2. the measurement of ICV diameter at the end of quiet expiration and collapse index calculation provide dependable indicators of central venous system volume ; and 3. ultrasonography enables recognition of a pathologic finding of increased transmural pressure gradient and better evaluation of right ventricle distention pressure.

Congestive heart failure ; Hepatic veins ; Inferior caval vein sonographic imaging ; Mueller maneuver ; Valsalva maneuver ; Ventilatory mechanics

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