title: Acute effects of intermittent positive pressure breathing in patients with chronic obstructive lung disease.
abstract: The immediate effects of intermittent positive pressure breathing (IPPB) on air were studied in seven patients (age 55-73 years) with advanced chronic obstructive lung disease (COLD) and with chronic respiratory insufficiency. Dynamic lung compliance was reduced by an average of 25% by IPPB, while inspiratory resistance increased by 40%. Distribution of inspired gas, as determined by nitrogen washout, became more even with IPPB. Respiratory frequency was not altered, whereas total ventilation increased by 25% during IPPB and PaCO2 was reduced. Oxygen uptake was reduced by 6%. PaO2 did not change during IPPB but had decreased by an average of 20% 10 minutes after IPPB and then slowly improved; PaCO2 did not change after IPPB. The pressures in the right atrium, pulmonary artery, and in pulmonary wedge position all increased approximately 2 mm Hg (approximately 2 cm H2O) with IPPB, while intrathoracic pressure rose on an average by 5 cm H2O, the transmural pressures thus being lowered during IPPB. The pulmonary vascular resistance was not significantly altered by IPPB, whereas the systemic vascular resistance rose 25%. Cardiac output was reduced approximately 20% and venous admixture almost 50%.
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D006328:Cardiac Catheterization; D002302:Cardiac Output; D002908:Chronic Disease; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007384:Intermittent Positive-Pressure Breathing; D008173:Lung Diseases, Obstructive / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011175:Positive-Pressure Respiration; D012119:Respiration; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy; D014692:Ventilation-Perfusion Ratio; D014797:Vital Capacity
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen