Quantitative Assessment of Blood Pressure Measurement Accuracy and Variability from Visual Auscultation Method by Observers without Receiving Medical Training

This study aimed to quantify blood pressure (BP) measurement accuracy and variability with determinations from visualizing Korotkoff sound waveform. Thirty video clips of BP recordings from the educational training database of the British Hypertension Society were converted to Korotkoff sound waveforms. Ten observers without receiving medical training were asked to determine systolic and diastolic BPs (SBP and DBP) from the randomly arranged video clips and Korotkoff sound waveforms using two measurement methods: a) traditional manual auscultatory method of listening for Korotkoff sounds; and b) visual auscultation method by visualising the Korotkoff sound waveform, which was repeated three times on different days, making a total of 6 BP measurements from each observer on each BP recording. The measurement variability was calculated from the standard deviation of the three repeats, and the measurement error was calculated against the reference answers. Statistical analysis showed that, in comparison with the traditional manual auscultatory method, visual auscultation method significantly reduced overall measurement variability from 2.2 to 1.1 mmHg for SBP and from 1.9 to 0.9 mmHg for DBP (both p<0.001). It also showed that BP measurement errors were significant for both techniques (all p<0.01, except DBP from the traditional method). Although significant, the overall mean measurement errors were small, which were -1.5 and -1.2 mmHg for SBP, and -0.7 and 2.6 mmHg for DBP, respectively from the traditional manual auscultatory and visual auscultation methods. In conclusion, the visual auscultation method had the ability to achieve an acceptable degree of BP measurement accuracy, with smaller measurement variability in comparison with the traditional manual auscultatory method.