Servoregulation of Centrifugal Pumps

Abstract

The objective of this study was to evaluate the principle technical requirements to servoregulate a centrifugal pump (Bio-Pump) and to discuss the potential risks and benefits of the potential use of such a device during long-term extra-corporeal support in an experimental laboratory study. A pressure control module (PCM) for the Bio-Pump was developed and a pressure measurement chamber to indirectly measure pressure in the venous limb of an extracorporeal circuit was constructed. The performance of the PCM combined with the pressure measurement chamber was evaluated in an experimental test circuit by recording pressure changes after sudden clamping of the venous line with and without servoregulation. Without the PCM pressure dropped from baseline to approximately -200 mm Hg after clamping and remained at that level. With the PCM active the pump speed was automatically and immediately reduced and the preclamping pressure level (+/- 10 percent) was restored within 500 msec. In this laboratory setting the Bio-Pump could effectively and rapidly be servoregulated with a conventional controller and an indirect pressure monitoring system. A potential clinical use of this system could help to improve the safety without imposing additional risks such as air embolism or backflow.