Effects of different contacting pressure on the transfer function between finger photoplethysmographic and radial blood pressure waveforms

摘要

Background: The blood pressure (BP) waveform is suggested to reflect the whole-body blood supply distribution, but its non-invasive assessment is not sufficiently user friendly for practical applications. The present authors studied the correlation between BP and photo-plethysmography (PPG) waveforms, with the aim of determining the optimal range for contact pressure stimulation (PS) to produce a reliable transfer function in their harmonic parameters. Methods: Finger PPG and radial-artery BP signals were measured simultaneously and non-invasively on healthy volunteers (n = 45). PS of 0–200 mmHg was applied to the finger, and 1 min data sequences were recorded. In frequency-domain analysis, linear regression was applied to the calculated amplitude ratios or the first five harmonics between BP and PPG waveforms. Results: In the 60 mmHg-PS group, the BP–PPG regression of amplitude ratios was highest, and the agreements between them were also the best verified by Bland–Altman analysis. Conclusion: In the present study, frequency-domain analysis was performed to study the correlation between BP and PPG waveforms. Differences in pressure-induced-vasodilation responses underlie the different BP-PPG waveform correlations obtained by applying different PSs. The non-invasively derived PPG parameters might help to provide an easier method to acquire the radial-artery BP waveform, and hence broaden the application of BP waveform analysis.