Experimental evaluation of the Dideco Masterflo paediatric hollow-fibre membrane oxygenator

Abstract

Nine mongrel dogs (mean bodyweight: 29 ± 6kg) were connected to cardiopulmonary bypass byfemorojugularvenous and femoral arterial cannulation, classic roller pump and the integrated Dideco D702 Masterflo hollow-fibre membrane oxygenatorwith a mean flow rate of 70ml/kg/min for six hours. Then the animals were weaned from cardiopulmonary bypass and thereafter weaned from the ventilator. After seven days all animals were sacrificed electively for necropsy. A standard battery of blood samples was taken before the bypass, after mixing (10 minutes), after two hours, five hours and six hours of perfusion. Further samples were taken 30 minutes after bypass (spontaneous breathing), 60 minutes after bypass (after extubation), 24 hours after bypass, 48 hours after bypass and seven days after bypass. Physiologic blood gas values could be maintained throughout perfusion in all animals. Mean arterial oxygen saturation varied between 99.7% and 99.9% for the arterial side of the oxygenator compared to 77.8% and 86.6% on the venous side. Post bypass blood gas analyses showed physiologic values and no evidence of major lung trauma or pulmonary oedema in relation to the six hours' bypass. Red blood count was 5.84 ± 0.02 before and 4.63 + 0.1 million/mm3 after mixing and dropped to 3.89 ± 0.52 till the end of the bypass. After seven days the red blood count was practically normalized with over 5,000,000 erythrocytes per mm3 at the end of the observation. Blood trauma evaluated in function of plasma haemoglobin and (thrombocyte) depletion showed the following results: prebypass: 2.3 ± 0.7 μmol/l plasma haemoglobin and (220 ± 24 thousand thrombocytes per mm3); after six hours perfusion: 26.2 ± 15.5 and (137 ± 12); after seven days: 9.3 ± 4.1 and (400 ± 125). Post mortem studies did not demonstrate any deleterious lesions.