We often employed PUF in heart-lung machine, while many doctors

The PUF device is only a separate package with many tiny tubing inside. It works when ever the package is hooked onto the heart- lung machine. If the heart of the patient get over-extended after weaning off, we have to re-start the heart-lung machine trying weaning off time by time. If the heart will not pump enough blood volume out ( because of less ejection percentage), then, we have to hook the PUF to the heart-lung machine, resulting in a huge amount of water leaving the patient. The patient heart would then work well with a smaller circulation volume.