Performance of a cuffless photoplethysmography-based device for continuous monitoring of blood pressure after cardiac surgery: a preliminary validation study

Accurate and convenient monitoring of blood pressure (BP) is challenging and relies on cuff-based devices or in the postoperative/intensive care settings, on invasive measurements. The aim of this study was to prospectively evaluate the accuracy of BP measurements obtained from a novel, commercially available cuffless, non-invasive photoplethysmography (PPG)-based chest patch monitor in patients after cardiac surgery. This single center prospective preliminary validation study enrolled adults who underwent cardiac surgery. Data generated by the PPG-based device was compared to those of a standard invasive arterial pressure (IAP). Bland-Altman plots and Pearson’s correlations were used to assess the accuracy of the PPG-based device. Stability and BP changes were not formally evaluated. Ninety-six patients consented for the study. Mean age was 63.2 ± 12.2 years (range 24–84), and 32 (33%) were women. Average monitoring was 25.6 ± 17.2 h. In total, we evaluated 78,659 readings for systolic BP (SBP), 78,818 for diastolic BP (DBP), and 92,544 for heart rate (HR). The correlation coefficients were r = 0.959, 0.973, 0.966, and 0.962 for SBP, DBP, mean arterial pressure (MAP), and (HR), respectively. The bias ± SD was 0.1 ± 4.8 mmHg for SBP; 0.4 ± 2.1 mmHg for DBP; 0.26 ± 2.6 mmHg for MAP, and 0.15 ± 3.6 beats per minutes for HR. 95% of SBP, and 99.9% of DBP measurements were within 10 mmHg of the reference measurement. In conclusion, the tested cuffless device offers acceptable accuracy and is a promising novel noninvasive tool for continuous BP monitoring. Further studies are needed to validate these findings according to the most updated validation protocols for pulseless devices. ClinicalTrials.gov ID NCT04071015.