We investigated the effect of membrane bio-incompatibility on cardiovascular stability in 10 patients with combined acute hepatic and
renal failure during 44 isovolemic intermittent machine
hemofiltration treatments, using a
polyamide membrane in 24 and a
polyacrylonitrile membrane in 20. Cardiac output decreased by 14 +/- 2% during
polyamide treatment compared to 8 +/- 3% during
polyacrylonitrile (P < 0.05). Pulmonary artery occlusion pressure decreased by 20% or more in 65% of the
polyamide treatments compared to 38% of the
polyacrylonitrile (P < 0.05). Tissue
oxygen delivery decreased by 16 +/- 2% during
polyamide treatment compared to 6 +/- 3% during
polyacrylonitrile treatment (P < 0.05). Mean arterial blood pressure declined from 80 +/- 3 mm Hg to 70 +/- 2 mm Hg during
polyamide treatment (P < 0.001), whereas there was no significant change during
polyacrylonitrile treatment. Thus, in this group of
critically ill patients, the use of two different membranes was associated with greater cardiovascular stability with
polyacrylonitrile treatment compared to
polyamide, with respect to maintenance of tissue perfusion and perfusion pressure. This suggests that extracorporeal membrane bio-incompatibility may have a role in determining cardiovascular stability during treatment with extracorporeal circuits.