The Journal of Thoracic and Cardiovascular Surgery, Vol 75, 839-846, Copyright © 1978 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Pulmonary gas exchange during venoarterial bypass with a membrane lung for acute respiratory failure
F Lemaire, F Jardin, B Regnier, D Loisance, B Goudot, F Lange, MC Eveleigh, B Teisseire, D Laurent and M Rapin
In patients with fulminating pulmonary edema not responsive to conventional
therapy, venoarterial membrane lung bypass can provide assistance if
decreased systemic blood pressure prevents use of high- level positive
end-expiratory pressure ventilation. In 10 patients with acute respiratory
failure, partial venoarterial bypass provided a rapid and marked
improvement of systemic oxygenation. Measurement of pulmonary blood flow
(PBF) and intrapulmonary shunting (QS/QP) during bypass via prolonged left
heart catheterization showed that left ventricular PaO2 was increased
through a rapid and profound reduction of QS/QP. During the first days of
bypass, derecruitment of pulmonary vessels is probably the mechanism of
improved pulmonary oxygenation. When low pulmonary arterial pressures (PAP)
are sustained, resorption of pulmonary edema is favored. Despite the
beneficial effects of bypass, death occurred in every case due to diffuse
interstitial fibrosis and/or parenchymal damage. The absence of healing,
due to prolonged circulatory exclusion, may be detrimental despite
immediate improvement. Because of this possibility, venovenous or mixed
perfusion should be more extensively explored.
