Computerised Analysis of Vascular Laboratory Data

Abstract

In the vascular laboratory at the Middlesex Hospital we perform many tests of arterial and venous function. The tests of arterial function use Doppler ultrasound and involve recording the velocity waveforms and ankle systolic pressures. Investigations of venous function include photoplethysmography and foot volumetry, tests for reflux and a strain gauge test for venous outflow. We also have facilities for measuring the pressure in the dorsal foot vein during ambulation as an assessment of venous function and reflux. Originally all these tests were performed with the aid of dual-channel chart recorders which produced one trace for each lower limb. This inevitably produced large amounts of data, many of which were not used in evaluating the patient and required the application of ruler and calculator to determine the parameters we wished to know. The process of examining the recorded traces and producing the final report was therefore very time-consuming and significantly reduced the numbers of patients that could be investigated by one person. It was with these problems in mind that we turned to the computer for help with the tasks of the vascular laboratory.