WAVE-FORM SHAPE-ANALYSIS - EXTRACTION OF PHYSIOLOGICALLY RELEVANT INFORMATION FROM DOPPLER RECORDINGS

1. Doppler recordings were made from the brachial artery of healthy fe male subjects during a series of manoeuvres which altered the pressure -flow characteristics of the vessel. 2. Changes were induced in the pe ripheral circulation of the forearm by the application of heat or ice- packs. A sphygmomanometer cuff was used to create graded occlusion of the vessel above and below the point of measurement. Recordings were a lso made whilst the subjects performed a standardized Valsalva manoeuv re. 3. The Doppler recordings were analysed both with the standard wav eform indices (systolic/diastolic ratio, pulsatility index and resista nce index) and by the method of Laplace transform analysis. 4. The wav eform parameters obtained by Laplace transform analysis distinguished the different changes in flow conditions; they thus had direct physiol ogical relevance, unlike the standard waveform indices.