The following conclusions were obtained from the study made to determine dose of heparin in periodically performed long term hemodialysis. Although the minimal requirement of heparin to prevent extracorporeal clotting during dialysis varies considerably from case to case, this remains within narrow range in individual case of repeated dialysis, if unaccompanied with complications.
The initial heparin dose can be calculated from our formula given below.
Initial dose of heparin (unit) =0.1×40/A ×circulatory blood volume×1.4
A: Clotting time of 1ml of blood from the patient, mixed in vitro with 0.1 unit of heparin.
On the other hand, the maintenance dose of heparin per hour, which is in the range of 70-140% of initial dose, can be determined during dialysis. The dose should also be considered on the basis of the dialyser in use. Coil type dialiser requires the prolongation of clotting time to 3-4 times as that before the starting of dialysis (L. W. 40-50min.).
