The objective of this investigation was to evaluate and compare the recently released Gish Vision oxygenator with previously studied oxygenators. We utilized our previously described membrane oxygenator evaluation techniques as well as proposed the use of four new performance indices: 1) oxygen transfer index; 2) shunt fraction index; 3) pressure drop index; and 4) consistency index. We concluded that the new Gish Vision membrane oxygenator offers the clinician the highest level of oxygen transfer "reserve" of any oxygenator we have tested. The use of our proposed performance indices enables the perfusionist to quickly and objectively compare various oxygenator performance characteristics and make a meaningful clinical comparison.