Validation of a transit time blood flow meter used for coronary bypass surgery

The validation of a blood flow meter is presented. This flow meter is based on the transit time method that uses two ultrasound transducers and a reflector. The measuring is based on the time difference of the upstream and the downstream ultrasound transit time. The validation was based on the norm ANSI Std. N42.17A-2003 of blood flow protocol. We used a flow simulator system with 3 mm pipe, bi-distilled and desgasificated water as fluid. Flow simulator system uses a constant flow pump, regulated by a valve, and a peristaltic flow pump, regulated by a variable voltage source, like flow source through the pipe.