Extracorporeal life support (ECLS) systems have been increasingly applied to groups of patients with cardiorespiratory failure, including pediatric and adult patients with respiratory failure. Current pulsatile ECLS systems use a single pulsatile blood pump that generates a high inlet pressure in the membrane oxygenator. To minimize this high inlet pressure, we have developed a new and improved ECLS system, twin pulse life support (T-PLS). To analyze the advantages of T-PLS, we have compared T-PLS with a single pulsatile ECLS system. An acute heart failure model was constructed by using a pulmonary artery banding technique. Fourteen pigs (22-31 kg) were used, with cardiac outputs of 2.0 l/min and a V/Q ratio set at 1. Cannulae of 28 Fr and 18 Fr were used in the right atrium and aorta, respectively. A polypropylene hollow-fiber membrane oxygenator and four polymer valves 30 mm in diameter were used in the T-PLS system. In the single pulsatile ECLS system, Medtronic Hall monostrut valves were used. To evaluate blood cell trauma in both pulsatile ECLS systems, plasma free hemoglobin (fHb) was measured while the systems were in use. The results show that fHb levels in T-PLS are lower than fHb levels in the single pulsatile ECLS system. There is a possibility that T-PLS could be used as an ECLS system for emergency situations.