Blood Pressure Monitoring after Cardiac Surgery using a Wearable, Non-Invasive Sensor - The 68th Annual Conference of the Israel Heart Society in association with the Israel Society of Cardiothoracic Surgery

Eitan Keizman ¹ Keren Constantini ² Dean Nachman ^3,4 Shemy Carasso ¹ Liza Grosman-Rimon ¹ Romi Littman ⁵ Arik Eisenkraft ^3,5 Yftach Gepner ² Erez Kachel ¹

¹Division of Cardiovascular Medicine and Surgery, Padeh Poriya Hospital, Israel
²Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine and Sylvan Adams Sports Institute, Tel Aviv University, Israel
³Institute for Research in Military Medicine, he Hebrew University of Jerusalem and the Israel Defense Force Medical Corps, Israel
⁴Heart Institute, Hadassah Ein Kerem Medical Center, Israel
⁵LTD, Biobeat Technologies, Israel

Introduction:

Continuous blood pressure (BP) measurement in intensive care units (ICU) is based on arterial line (AL) transducers, which is technically complex and may be associated with clinical complications, including infection, bleeding and radial nerve damage. The aim of this study was to evaluate the accuracy of continuous BP measurements obtained from a non-invasive photoplethysmography (PPG)-based device using two distinct configurations, wristwatch and chest-patch, compared to AL in patients following cardiac surgery.

Methods:

Ten patients were recruited for this prospective study. Pulse rate (PR), systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) were recorded in parallel using AL and the PPG-based device for an average of 432±290 min starting immediately after cardiac surgery. Bland-Altman plots and Pearson`s correlations were used to assess the accuracy and degree of agreement between techniques.

Results:

Total of ~4,000 data points were collected and included in the final analysis. AL measurements for PR, SBP, DBP and MAP were significantly (p<0.001) and strongly correlated with both wristwatch (r=0.99, r=0.94, r=0.93 and r=0.96, respectively) and the chest-patch (r=0.99, r=0.95, r=0.93 and r=0.95, respectively). Both configurations showed a marginal bias of <1 mmHg for BP measurements and <1 beat/min for PR [95% limits of agreement -3,3 beat/min; BP measurements: (-6)-(-10),6-10 mmHg] compared to AL measurements.

Discussion:

The PPG-based devices offers a high level of accuracy for cardiac-related parameters compared to data obtained invasively by AL in post-cardiac surgery patients. These devices have advanced monitoring capabilities in a variety of clinical settings, including immediate postoperative and ICUs.