Respiratory gas exchange through the hydrophilic membrane

To assess the efficiency of respiratory gas exchange in vitro through a dialysis membrane mounted inside a flat plate Kiil dialyzer, the model reactions of hydrogen peroxide reduction by a metal ion and of the carbon dioxide precipitation in the form of a carbonate in the dialysate were used. A comparison of the rates of oxygen output obtained for a membrane fixed in the test chamber and those for a membrane inside the dialyzer showed that the performance of the membrane as an oxygen source in the latter arrangement is much poorer than that in the former one. This was attributed to the inadequate dialysate channel geometry of the dialyzer with respect to the catalytic reaction. However, the dialyzer geometry did not impede a quick removal of carbon dioxide. Washout of the catalyst (cobalt oxide) was observed. Hydrogen peroxide leakage to the blood side of the membrane was negligible.