Optimum end-expiratory airway pressure in patients with acute pulmonary failure.
To determine whether in the management of pulmonary failure, the maximum compliance produced by positive end-expiratory pressure coincides with optimum lung function, 15 normovolemic patients requiring mechanical ventilation for acute pulmonary failure were studied. The end-expiratory pressure resulting in maximum oxygen transport (cardiac output times arterial oxygen content) and the lowest dead-space fraction both resulted in the greatest total static compliance. This end-expiratory pressure varied between 0 and 15 cm of water and correlated inversely with functional residual capacity at zero end-expiratory pressure (r equal -0.72, p less than or equal to 0.005). Mixed venous oxygen tension increased between zero end-expiratory pressure and the end-expiratory pressure resulting in maximum oxygen transport, but then decreased at higher end-expiratory pressures. When measurements of cardiac output or of true mixed venous blood are not available, compliance may be used to indicate the end-expiratory pressure likely to result in optimum cardiopulmonary function.
D000328:Adult; D000368:Aged; D000403:Airway Resistance; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D005260:Female; D006371:Helium; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008168:Lung / Q000503:physiopathology; D008170:Lung Compliance; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration; D011312:Pressure; D011656:Pulmonary Emphysema / Q000503:physiopathology; D012119:Respiration; D012131:Respiratory Insufficiency / Q000503:physiopathology* / Q000628:therapy; D013147:Spirometry
D002245:Carbon Dioxide; D006371:Helium; D010100:Oxygen