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Noninvasive Determination of Blood Pressure by Heart Sound Analysis Compared With Intra-Arterial Monitoring in Critically Ill Children—A Pilot Study of a Novel Approach

Kapur, Gaurav MD1; Chen, Lingguang PhD2; Xu, Yong PhD3; Cashen, Katherine DO1; Clark, Jeff MD1; Feng, Xiaoce PhD3; Wu, Sean F. PhD2

Pediatric Critical Care Medicine: September 2019 - Volume 20 - Issue 9 - p 809-816
doi: 10.1097/PCC.0000000000001997
Cardiac Intensive Care

Objectives: To develop a novel device to predict systolic and diastolic blood pressure based on measured heart sound signals and evaluate its accuracy in comparison to intra-arterial blood pressure readings.

Study Design: Prospective, observational pilot study.

Setting: PICU.

Patients: Critically ill children (0–18 yr) undergoing continuous blood pressure monitoring via radial artery intra-arterial catheters were enrolled in the study after informed consent. The study included medical, cardiac, and surgical PICU patients.

Interventions: Along with intra-arterial blood pressure, patient’s heart sounds were recorded simultaneously by a highly sensitive sensor taped to the chest. Additional hardware included a data acquisition unit and laptop computer. Subsequently, advanced signal processing technologies were used to minimize random interfering signals and extract and separate S1 and S2 signals. A computerized model was then developed using artificial neural network systems to estimate blood pressure from the extracted heart sound analysis.

Measurements and Main Outcomes: We found a statistically significant correlation for systolic (r = 0.964; R2 = 0.928) and diastolic (r = 0.935; R2 = 0.868) blood pressure readings (n = 491) estimated by the novel heart-sound signal–based method and those recorded by intra-arterial catheters. The mean difference of the individually paired determinations of the blood pressure between the heart-sound–based method and intra-arterial catheters was 0.6 ± 7 mm Hg for systolic blood pressure and –0.06 ± 5 mm Hg for diastolic blood pressure, which was within the recommended range of 5 ± 8 mm Hg for any new blood pressure devices.

Conclusions: Our findings provide proof of concept that the heart-sound signal-based method can provide accurate, noninvasive blood pressure monitoring.

1Department of Pediatrics, Children’s Hospital of Michigan/Wayne State University, Detroit, MI.

2Department of Mechanical Engineering, Wayne State University, Detroit, MI.

3Department of Electric and Computer Science Engineering, Wayne State University, Detroit, MI.

Drs. Kapur and Chen contributed equally to the article.

This work was supported by the 21st Century Jobs Trust Fund received through the Michigan Strategic Fund from the State of Michigan and administered by the Michigan Economic Development Corporation (

Dr. Kapur’s institution received funding from Alexion; a nonprovisional patent (number PCT/US18/17178) titled, “Method and Apparatus for Determining Blood Pressure on Measured Heart Sounds,” based on this research was submitted on 02/07/2018 (to Drs. Kapur, Chen, Xu, and Wu listed as co-inventors); and he disclosed off-label product use of the technology reported in the article, which is currently investigational and not approved by the U.S. Food and Drug Administration for any purposes. Drs. Kapur and Chen disclosed that this work was supported by the 21st Century Jobs Trust Fund received through the Michigan Strategic Fund from the State of Michigan and administered by the Michigan Economic Development Corporation. Dr. Xu disclosed work for hire. The remaining authors have disclosed that they do not have any potential conflicts of interest.

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Copyright © 2019 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies