MUF is known to improve post-CPB hemodynamics in infants and children. Some perfusionists speculate that this effect occurs because MUF removes inflammatory mediators from the blood. However, the explanation is probably much simpler. MUF increases the plasma proteins in the residual circuit blood and combines it with the patient’s blood in the right atrium. This high oncotic blood goes directly to the lungs where it removes interstitial pulmonary fluid by osmosis. This modifies the pulmonary vascular bed to such as degree that hemodynamics quickly improve.
Additional benefits of MUF include an increase in the plasma proteins, clotting factors and hematocrit without increasing the circulating blood volume. The key to obtaining these benefits lies in the ratio of the amount of MUF blood flow to the patient’s right atrial venous return flow. In an infant, the MUF blood flow is about 1/5th of the patient’s total cardiac output. As a result the oncotic pressure of the combined blood volumes is high. As the patient increases in size, this ratio changes and the benefits are reduced.
Perfusion Theory is an educational platform for the Oxygen Pressure Field Theory (OPFT). August Krogh’s theoretical concept of the oxygen pressure field is explained and then applied to clinical applications in perfusion practice.