Mock Circulation to Test Pumps Designed for Permanent Replacement of Damaged Hearts
WILLEM J. KOLFF, M.D.
Department of Artificial Organs, and Division of Research
IN the future it may become feasible to replace an irreparably damaged heart with a permanently indwelling mechanical pump to propel the blood through both the pulmonary and the systemic circulation. Setting aside for the moment the problems concerning clotting and injury to the blood cells or plasma, such a pump requires the mechanical definition as follows.
It should be a small double pump (right heart, left heart).
The pumping rate should be variable between 60 and 160 strokes per minute.
The output volume should be variable between 1.5 and no less than 5 liters per minute for each side of the pump.
The input pressure or ‘atrial’ pressure should be no more than 16 mm. of Hg, and no less than 0. In other words, suction should not be strong when available blood is not sufficient to fill the heart.
The output pressure of the right ‘ventricle’ should be 20 but capable of increasing to 80 mm. of Hg. The output pressure of the left ‘ventricle’ should be 120 but capable of increasing to 180 mm. of Hg.
The 24-hour output of the left side must equal that of the right side: the filling of each ‘atrium’ must determine the output of the corresponding ‘ventricle.’
It is not absolutely necessary that the ‘atria’ contract, but the diastole should be sufficiently long to allow filling of the ‘ventricles.’ Wiggers 1 gives an example of diastole both in man and in dogs of 0.53 . . .