Validation of a fully automatic photoplethysmographic device for toe blood pressure measurement.

Abstract

This study was designed to assess the accuracy and reliability of a new, portable, fully automated photoplethysmography (PPG) device for toe blood pressure (TBP) measurement. Within-subject comparison with conventional laser Doppler (LD) measurement. Four TBP measurements were performed on both lower limbs, alternatively with LD and PPG in 200 patients recruited at the Nîmes University Hospital. Reproducibility was assessed by the intraclass correlation coefficient (ICC). The concordance between the two methods was evaluated by Lin's concordance correlation coefficient (CCC), in the whole population as well as in comorbidity subgroups. A potential bias was investigated with the Bland and Altman method. The ICC was 0.887 (95% confidence interval (CI) 0.852-0.913) and 0.893 (0.860-0.918) on the right side (n = 193), 0.905 (0.875-0.928) and 0.898 (0.866-0.922) on the left side (n = 188) for PPG and LD measurements, respectively. The CCC was 0.913 (0.885-0.934) on the right side and 0.915 (0.888-0.937) on the left side, and remained >0.8 regardless of co-morbidities. This new, fully automatic, photoplethysmographic device yielded reliable TBP measurements and showed good agreement with the reference LD system over a wide range of values.