Validation of a Novel, Non-Invasive, Continuous Blood Pressure Monitor in a Cohort of Patients Undergoing Surgery with General Anesthesia

Document Type

Conference Proceeding

Publication Date

5-1-2025

Publication Title

Anesth Analg

Keywords

Anesthesiology

Abstract

Introduction: Blood pressure (BP) monitoring is a core component of perioperative care, with beat-to-beat monitoring advocated for those at risk of harm from hemodynamic instability. The current standard of care for continuous BP monitoring is intraarterial, with an estimated 8 million performed in the United States every year1. The procedure requires a highly trained clinician, and introduces risks that include hematoma, thrombosis, infection, and temporary vascular occlusion2-3. The alternative to arterial line continuous monitoring is a non-invasive blood pressure (NIBP) cuff, but this approach only provides intermittent measurements every 3-5 minutes, potentially delaying detection of critical hemodynamic events. This study aims to validate a novel non-invasive, continuous blood pressure (NIcBP) device for intraoperative continuous BP monitoring under general anesthesia. The device consists of a stretchable sensor that sits comfortably over the dorsalis pedis artery and measures arterial expansion as blood pumps through the artery with each heartbeat. Data is transferred wirelessly to a tablet where the arterial waveform and BP values are displayed to the medical team.Methods: Following local IRB approval at two study sites, 12 patients were consented and enrolled in the study. Inclusion criteria consisted of patients with a palpable dorsalis pedis pulse undergoing surgery in supine position under general anesthesia with intraarterial BP monitoring. Exclusion criteria consisted of patients requiring intraoperative neuromonitoring or mechanical BP support. Of the 12 patients monitored to date, one was excluded due to intraoperative position change. The NIcBP device was placed over the dorsalis pedis artery upon arrival to the operating room. BP measurements are available upon device activation. Once the medical team completes roll-call, an initial set of 6 NIBP cuff measurements are used for calibration (approximately 3-5 minutes apart). After the initial calibration, continuous measurements from the NIcBP device were collected for analysis, and additional NIBP cuff calibrations entered when prompted by the device. Segments of data with arterial line dysfunction due to dampening, flushing, blood draws, or motion artifacts were excluded from analysis. The systolic and diastolic mean bias and standard deviations were calculated between the NIcBP device and the arterial line in a Bland-Altman analysis. Results: For each of the patients, the resulting systolic and diastolic mean biases and standard deviations are shown in Table 1. For 10 out of the 11 patients, the values fall within the ISO 81060-2 guidelines used by the FDA for evaluating BP device accuracy (mean bias ≤ 5 mmHg and standard deviation ≤ 8 mmHg)4. Figures 1 and 2 show the measured BP for the arterial line and the NIcBP device BP for the comparison duration for patients from UCI and HFH, respectively.Conclusions: The NIcBP device demonstrated strong agreement to the arterial line for the majority of subjects monitored thus far, meeting the ISO standards for BP accuracy. BP changes including major hypo- and hypertensive events were also properly tracked. Limitations of the study include the low number of patients enrolled thus far, as the study targets an additional 80 patients across the two study sites within the next six months. Another limitation is that the current measurement protocol does not explicitly include the induction and intubation period, where accurate continuous monitoring may also be desirable. Despite these limitations, the early data shows that the NIcBP device may be a potential alternative to intraoperative invasive BP monitoring, reducing interventions and saving operating room time. In procedures where an arterial line is not indicated, the device may also be used as a supplement to the NIBP cuff to provide more responsive continuous monitoring, enabling faster identification of hemodynamic changes, early interventions and real-time assessment of their outcomes. Future potential applications of this NIcBP device include post operative, telemetry, and critical care units, sleep studies, and ambulatory/home BP monitoring.

Volume

140

Issue

5

First Page

1080

Last Page

1083

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