Lung extravascular volume during venovenous bypass with extracorporeal CO2-removal in dogs.

Extracorporeal circulation can cause lung damage, which would be especially counterproductive during extracorporeal gas exchange for the treatment of acute respiratory failure. To test the hypothesis that partial venovenous bypass with extracorporeal CO2-removal combined with low-frequency positive pressure ventilation (ECCO2R-LFPPV) can adversely affect lung fluid balance, extravascular thermal lung volume (ETV) and hemodynamics were assessed before, during and after ECCO2R-LFPPV in normal closed chest dogs. In series I dogs (n = 6) subjected to 10 h of ECCO2R-LFPPV, ETV did not change significantly from control (7.1 ml/kg +/- 0.99 SE) during or after bypass. Gravimetric extravascular lung water and lung histology after bypass were found to be normal. In series II dogs (n = 5), subjected to shorter periods of ECCO2R-LFPPV, ETV also remained unchanged. In contrast to previous reports using sheep, pulmonary arterial hypertension during bypass was not observed. Thus, ECCO2R-LFPPV was not associated with increased lung water, pulmonary hypertension or morphological lung changes under the conditions studied and does not seem to cause lung damage in normal lungs.

[Pulmonary function during a 10-day successful extracorporeal CO2 elimination in acute respiratory failure. Case report]. / Lungenfunktion während 10-tägiger erfolgreicher extrakorporaler CO2-Elimination bei schwerem akuten Lungenversagen. Fallbricht.

Extracorporeal CO2-removal (ECCO2-R) with low-frequency positive-pressure ventilation (LFPPV) may relieve the acutely injured lung from the burden and the risks of excessively high ventilatory minute volumes and airway pressures. It was the purpose of this study to document the evolution of lung function during clinical ECCO2-R with special emphasis on extravascular lung water. ECCO2-R was applied in a 21-year-old female patient suffering from severe post-traumatic infectious adult respiratory distress syndrome. The indication for ECCO2-R was based on the following findings: total static lung compliance 25 cm X cm H2O-1; arterial pO2 50 mm Hg with an inspiratory oxygen concentration of 100%; intrapulmonary right-to-left shunt over 50% of the cardiac output; and extravascular lung water 24 ml X kg-1 (normal 4.5-7 ml X kg-1). ECCO2-R was shown to provide satisfactory conditions for improving the above-mentioned abnormal parameters of pulmonary function. Pressure-limited low-frequency mechanical ventilation allowed successful management of several pneumothoraces with bronchopleural fistulas which occurred during the procedure. It is concluded that these complications of positive airway pressure would have led to the patient's death under the conditions of conventional mechanical ventilation.