Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas
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Braz. J. Med. Biol. Res. · Jul 1983
Relationship between mouth and esophageal pressures in different body postures.
Static voluntary efforts, both inspiratory and expiratory (executed with the glottis open against a closed airway) are commonly utilized for the evaluation of correct esophageal balloon positioning for indirect pleural pressure measurement. Agreement between delta Pm (change in mouth pressure) and delta Pes (change in esophageal pressure) indicates the valid indirect determination of pleural pressure. Measurements of delta Pes are more commonly made with the thorax in the upright position, and some investigators have reservations about determinations carried out in the supine position. ⋯ Phase differences between delta Pes and delta Pm were very small in different body positions. Cardiac artifacts in esophageal measurements were more pronounced in the horizontal and -10 degrees positions. The "occlusion test" is particularly useful for clinical application because it does not require patient cooperation and is a very simple technique for evaluating correct esophageal catheter placement.