Osamu Minamikawa

Safe limit of hemodilution in cardiopulmonary bypass -comparative analysis between cyanotic and acyanotic congenital heart disease.

A safe limit of hemodilution in cardiopulmonary bypass (CPB) for open heart surgery was investigated by analyzing of the perfusion results of 100 patients with tetralogy of Fallot (TOF) and ventricular septal defect (VSD). The higher perfusion flow was necessary to compensate for the reduced oxygen carrying capacity and to maintain adequate arterial pressure in proportion to the increase in hemodilution. Once the dilution ratio reached over 40% in TOF and 50% in VSD, however, adequate oxygen transfer and stable hemodynamic conditions could not be maintained. The former was due to inadequate oxygen delivery and the latter to an impaired venous return. In these cases, various complications caused by residual diluent in the body space despite of extensive diuretic therapy occurred immediately postop.The safe limit of hemodilution is 50%. However, that of cyanotic disease, even in the presence of a remarkable polycythemia, must be limited to less than 40%.

Hemodynamic effects of prostaglandin E1 during cardiopulmonary bypass in infants and children

Effects of prostaglandin E1 (PGE1) and phenoxybenzamine (POB) on the hemodynamics during cardiopulmonary bypass (CPB) were studied in 30 infants and children. Patients were grouped into three; PGE1 was given to ten patients, POB to another ten, and the other ten patients served as the control. Vasodilative drugs were witheld. PGE1 was infused at 0.01 to 0.02 μg/kg/min during CPB, and POB at 1.0 mg/kg within the initial 10 minutes of bypass. There was a significant drop in arterial and venous pressure at the time of initiation of bypass in both the PGE1 and POB groups. In the PGE1 group in particular, such a stable hemodynamic condition of over 60 mm Hg in mean arterial pressure, 7.5 to 12.5 cmH2O in central venous pressure, 1300 to 1700 dynes·sec·cm−5 in systemic vascular resistance was maintained throughout CPB, as compared with the other two groups. PGE1 contributed to an adequate diuresis and the preservation of platelets. Our findings indicate that PGE1 has potential clinical advantages for application during CPB.

High-flow total body perfusion with severe hemodilution and normothermia in infants weighing less than 10 kg--safe limits of hemodilution in cardiopulmonary bypass in infants.

Cardiopulmonary bypass with 17 to 57 per cent dilution of hemoglobin for repair of ventricular septal defect (VSD) was applied to 26 infants weighing less than 10 kg at normal temperature. The higher flow rate was required to compensate the reduced oxygen carrying capacity and to maintain an adequate arterial pressure in proportion to a decrease of hemoglobin value. Perfusion index resulted in 3.0 to 6.5 L/m2/min in this series. When the dilution ratio of hemoglobin became more than 50 per cent and high flow rate was required, however, oxygen transfer ratio decreased remarkably on account of inadequate oxygen delivery and impaired venous return. In these cases, it was difficult to remove the diluent immediately after the operation in spite of powerful diuretic therapy. The results of the present study indicate that the safe limits of hemodilution is 50 per cent in cardiopulmonary bypass at normal temperature in infants.