A DYNAMIC METHOD FOR SETTING ROLLER-PUMPS NONOCCLUSIVELY REDUCES HEMOLYSIS AND PREDICTS RETROGRADE FLOW

In general, roller pumps are set almost occlusively despite evidence t hat nonocclusive settings cause less hemolysis. Almost-occlusive setti ngs are used because of the concern that forward flow would not be acc urately known if retrograde flow were allowed to occur through a nonoc clusive gap. This article presents a dynamic method for setting roller pumps nonocclusively that overcomes the many difficulties of the ''dr op method'' for setting occlusion. Studies were conducted to determine the effect of nonocclusive settings on pump flow and hemolysis genera ted; the results suggest that roller pumps can and should be set more nonocclusively than is the currently accepted standard to reduce pump related hemolysis without greatly affecting pump performance. The dyna mic method allows retrograde flow to be easily predicted and corrected with an increase in pump speed.