An automatic pneumatically driven autotransfusion system: a hematologic evaluation in dogs.

An automatic, pneumatically driven autotransfusion system (ATS) was developed because ATSs driven by roller pumps are complicated to set up and require an experienced operator. In this ATS blood is aspirated into a cardiotomy reservoir by means of a constant vacuum applied on that reservoir. Damage to blood cells is reduced by an electronic device that regulates an automatic tubing clamp in the suction line to prevent suction of air along with blood (controlled suction). The blood is reinfused by a diaphragm pump driven by alternating vacuum and compressed air. The frequency of this pump is regulated by a level sensor in the cardiotomy reservoir to maintain a constant preset level. When we tested this automatic ATS in dogs, platelet function and platelet numbers substantially recovered after a dip during an autotransfusion period of 1 hour. Advantages of this ATS are that it causes only minor blood damage, it does not require a specially trained operator, and it is ready to use in every operating room. The diaphragm pump can be made disposable and integrated in the bottom of a cardiotomy reservoir.