Title: Clinical Effects of Membrane Lung Support for Acute Respiratory Failure
Abstract: Extrapulmonary support in respiratory failure has become possible for prolonged periods with clinical application of the membrane lung oxygenator.The membrane lung may be perfused in a venovenous circuit, in which case it functions by prepulmonary venous oxygenation, or it may be pumped in venoarterial perfusion as partial or total cardiopulmonary bypass.Four patients were placed on venovenous membrane lung (GE-Peirce) perfusion for periods ranging from 6 to 112 hours.In oxygenating blood flows of less than 50% of the cardiac output, a viable PaO, (mean, 52 mm Hg) was obtained in 2 patients with 60% F I ~, , including 1 survivor who was weaned from the membrane lung.The remaining 2 patients had heart failure and insufficient venovenous membrane lung flows to improve systemic oxygenation (mean P~Q,, 45 mm Hg on 100% F I ~J .Four other patients were placed on venoarterial membrane lung (GE-DuaLung) bypass for 18 to 110 hours.With 40 to 85% of the cardiac output bypassed through the membrane oxygenator, immediate improvement was seen in systemic oxygenation (mean Pao,, 75 mm Hg), effective compliance (mean increase of 75%), and reduction in pulmonary hypertension (mean decrease, 15 mm Hg).These changes during bypass allowed the lungs to be put at rest with a decrease in FIO, and positive end-expiratory pressures.This clinical experience indicates that venoarterial membrane lung bypass may be both supportive and therapeutic, decompressing the pulmonary circuit and maintaining systemic oxygenation.Membrane lung support by either mode of perfusion has been shown to be clinically effective in patients suffering acute respiratory failure.ulmonary insufficiency has emerged as a major cause of morbidity and mortality in shock, infectious disease, and other conditions treated in P intensive care units.A number of patients who suffer acute respiratory failure following these conditions might benefit from extrapulmonary oxygenation if their respiratory failure persists despite optimum conventional therapy.Extrapulmonary support for respiratory failure has become possible for prolonged periods with the advent of the membrane lung oxygenator.For those patients who fail to respond to volume ventilation, diuretics, and antibiotic management, or who suffer toxicity from high inspired oxygen tensions and positive end-expiratory pressures, the membrane lung may play a role in providing prolonged extrapulmonary respiratory support.