The Concordance of Respiratory Fluctuations in Oesophageal and Central Venous Pressures

Abstract

Respiratory fluctuations in oesophageal and central venous pressures were recorded in 13 healthy subjects and compared with respect to phase and amplitude concordance. An average divergence in phase of nearly 180° was obtained, with large inter- and intra-individual variations. Disregarding phase the amplitude of the respiratory central venous pressure was found to be, on the average, a good 1/4 of that of the oesophageal pressure in the supine posture, and a good 2/3 while the subjects were sitting. These figures also varied considerably. It is suggested that the findings might be referred to competition between a central venous pressure raising effect of inspiration enhanced venous return, and a central venous pressure depressing effect of the inspiratory fall in intrathoracic pressure. The partitioning of costal and abdomino-diaphragmatic breathing is considered of great significance to the outcome of this competition. It is concluded that the oesophageal balloon catheter technique for estimation of transpulmonary pressure cannot simply be replaced by the central venous catheter technique in healthy subjects. Its application in patients with certain pulmonary disorders, however, might be more successful.