Theoretical Analysis of Occlusion Techniques for Measuring Pulmonary Capillary Pressure

Abstract

GRIMBERT. Theoretical analysis of occlusion techniques for mea-suring pulmonary capillary pressure. J. Appl. Physiol. 73(4): 1351-1359,1992.-We have developed a model including three serial compliant compartments (arterial, capillary, and ve-nous) separated by two resistances (arterial and venous) for interpreting in vivo single pulmonary arterial or venous occlu-sion pressure profiles and double occlusion. We formalized and solved the corresponding system of equations. We showed that in this model 1) pulmonary capillary pressure (PC) profile after arterial or venous occlusion has an S shape, 2) the estimation of PC by zero time extrapolation of the slow component of the arterial occlusion profile (PC,,) always overestimates Pc, 3) symmetrically such an estimation on the venous occlusion pro-file (PC”,) always underestimates PC, 4) double occlusion pres-sure (PC & differs from PC. We evaluated the impact of varyin