THE EFFECT OF PROTEIN AND BLOOD-CELLS ON THE FLOW-PRESSURE CHARACTERISTICS OF SHUNTS

IT HAS LONG been assumed that a high cerebrospinal fluid protein conce ntration adversely affects the performance of shunts. There is little experimental evidence to support this viewpoint, however, and the few reports that have been published can be criticized for poor experiment al design or presentation of results. A flow-dependent shunt perfusion model was constructed. PS Medical Flow Control valves (PS Medical Cor poration, Goleta, CA) and Cordis-Hakim valves (Cordis Corporates, Miam i, FL) were perfused with saline-plasma solutions in concentrations fr om 0 to 9 g/L of protein. Blood suspensions in dilutions from 0.25 to 1% were also studied. The opening and closing pressures of the valves were measured with a simple manometer, and the physical properties of the solutions were studied. The results indicated that the valves perf ormed within the ranges specified by their manufacturers, even with ma rkedly increased protein concentrations in the perfusate. Furthermore, the valve opening and closing pressures were lower with the protein-c ontaining solutions than with the control solutions. Thus, the protein did not impair shunt function and we conclude that shunts can be inse rted into patients who have elevated cerebrospinal fluid protein conte nts. However, blood cells did adversely affect performance and, theref ore, patients with hemorrhagic cerebrospinal fluid should not receive shunts.