| A Paracorporeal Respiratory Assist Lung (PRAL) was developed for supplemental gas exchange to allow the native lungs of acute lung failure patients time to heal. The device consisted of a rotating annular microporous hollow fiber membrane bundle. The rotation augmented the gas exchange efficiency of the device at constant flowrate thereby uncoupling gas exchange and flowrate. The rotating fibers also enabled the PRAL to pump the blood without the need for an additional pump or arterial cannulation. A prototype was manufactured with an overall surface area of 0.42 m2, and CO2 removal rates were 101 ml/min at a blood flowrates of 0.75 L/min. When rotated at 1500 RPM, CO2 removal increased by 92% and O2 transfer increased by 88% over the stationary bundle during an in vitro bovine blood study. The pumping of the rotating fiber bundle was assessed, and at 1500 RPM the PRAL generated 750 ml/min against 52 mmHg pressure in water. Hemolysis of the device was assessed using in vitro bovine blood from a slaughterhouse. Plasma free hemoglobin levels were higher than the control, and we found that the roughness of the rotating fibers was the cause of much of the blood trauma. |
