Abstract
Purpose
Non-contact continuous respiratory rate monitoring is preferred for early detection of patient deterioration. However, this technique is under development; a gold standard respiratory monitor has not been established. Therefore, this prospective observational method comparison study aimed to compare the measurement accuracy of a non-contact continuous respiratory rate monitor, a microwave Doppler sensor positioned beneath the mattress, with that of other monitors.
Methods
The respiratory rate of intensive care unit patients was simultaneously measured using a microwave Doppler sensor, capnography, thoracic impedance pneumography, and a piezoelectric sensor beneath the mattress. Bias and 95% limits of agreement between the respiratory rate measured using capnography (standard reference) and that measured using the other three methods were calculated using Bland–Altman analysis for repeated measures. Clarke error grid (CEG) analysis evaluated the sensor’s ability to assist in correct clinical decision-making.
Results
Eighteen participants were included, and 2,307 data points were analyzed. The bias values (95% limits of agreement) of the microwave Doppler sensor, thoracic impedance pneumography, and piezoelectric sensor were 0.2 (− 4.8 to 5.2), 1.5 (− 4.4 to 7.4), and 0.4 (− 4.0 to 4.8) breaths per minute, respectively. Clinical decisions evaluated using CEG analyses were correct 98.1% of the time for the microwave Doppler sensor, which was similar to the performance of the other devices.
Conclusion
The microwave Doppler sensor had a small bias but relatively low precision, similar to other devices. In CEG analyses, the risk of each monitor leading to inadequate clinical decision-making was low.
Trial registration number
: UMIN000038900, February 1, 2020.
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Data Availability
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
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Acknowledgements
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Funding
This work was supported by Konica Minolta, Inc. (Tokyo, Japan). The microwave Doppler sensor and piezoelectric sensor used in this study were provided by Konica Minolta, Inc. The company was not involved in the study design, collection, analysis, and interpretation of data, writing of the manuscript, or the decision to submit the manuscript for publication.
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Hiroyuki Tanaka: Literature search, data collection, analysis of data, manuscript preparation, and manuscript review. Masashi Yokose: Literature search, data collection, study design, analysis of data, manuscript preparation, and review of manuscript.Shunsuke Takaki: Data collection, study design, and review of manuscript.Takahiro Mihara: Study design and review of manuscript.Yusuke Saigusa: Study design, analysis of data, and review of manuscript.Takahisa Goto: Review of manuscript.
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Shunsuke Takaki received funding for this study from Konica Minolta, Inc. The other authors have no competing interests to declare.
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This prospective observational study was conducted in accordance with the World Medical Association’s 1964 Declaration of Helsinki and approved by the Institutional Review Board of Yokohama City University Hospital (approval no. B190700013; July 17, 2019).
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Tanaka, H., Yokose, M., Takaki, S. et al. Measurement accuracy of a microwave doppler sensor beneath the mattress as a continuous respiratory rate monitor: a method comparison study. J Clin Monit Comput 38, 77–88 (2024). https://doi.org/10.1007/s10877-023-01081-7
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DOI: https://doi.org/10.1007/s10877-023-01081-7