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Hayward N, Shaban M, Badger J, Jones I, Wei Y, Spencer D, Isichei S, Knight M, Otto J, Rayat G, Levett D, Grocott M, Akerman H, White N. A capaciflector provides continuous and accurate respiratory rate monitoring for patients at rest and during exercise. J Clin Monit Comput 2022; 36:1535-1546. [PMID: 35040037 PMCID: PMC8763619 DOI: 10.1007/s10877-021-00798-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/23/2021] [Indexed: 10/27/2022]
Abstract
Respiratory rate (RR) is a marker of critical illness, but during hospital care, RR is often inaccurately measured. The capaciflector is a novel sensor that is small, inexpensive, and flexible, thus it has the potential to provide a single-use, real-time RR monitoring device. We evaluated the accuracy of continuous RR measurements by capaciflector hardware both at rest and during exercise. Continuous RR measurements were made with capaciflectors at four chest locations. In healthy subjects (n = 20), RR was compared with strain gauge chest belt recordings during timed breathing and two different body positions at rest. In patients undertaking routine cardiopulmonary exercise testing (CPET, n = 50), RR was compared with pneumotachometer recordings. Comparative RR measurement bias and limits of agreement were calculated and presented in Bland-Altman plots. The capaciflector was shown to provide continuous RR measurements with a bias less than 1 breath per minute (BPM) across four chest locations. Accuracy and continuity of monitoring were upheld even during vigorous CPET exercise, often with narrower limits of agreement than those reported for comparable technologies. We provide a unique clinical demonstration of the capaciflector as an accurate breathing monitor, which may have the potential to become a simple and affordable medical device.Clinical trial number: NCT03832205 https://clinicaltrials.gov/ct2/show/NCT03832205 registered February 6th, 2019.
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Affiliation(s)
- Nick Hayward
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK.
| | - Mahdi Shaban
- School of Electronics and Computer Science, University of Southampton, Southampton, UK
| | - James Badger
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - Isobel Jones
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK.,School of Electronics and Computer Science, University of Southampton, Southampton, UK
| | - Yang Wei
- School of Electronics and Computer Science, University of Southampton, Southampton, UK.,Department of Engineering, Nottingham Trent University, Nottingham, UK
| | - Daniel Spencer
- School of Electronics and Computer Science, University of Southampton, Southampton, UK
| | - Stefania Isichei
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - Martin Knight
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - James Otto
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - Gurinder Rayat
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - Denny Levett
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK
| | - Michael Grocott
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK.,Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
| | - Harry Akerman
- Perioperative & Critical Care Theme, Southampton NIHR Biomedical Research Centre, University Hospital Southampton / University of Southampton, Southampton, UK.,School of Electronics and Computer Science, University of Southampton, Southampton, UK
| | - Neil White
- School of Electronics and Computer Science, University of Southampton, Southampton, UK
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Tack B, Vita D, Mbaki TN, Lunguya O, Toelen J, Jacobs J. Performance of Automated Point-of-Care Respiratory Rate Counting versus Manual Counting in Children under Five Admitted with Severe Febrile Illness to Kisantu Hospital, DR Congo. Diagnostics (Basel) 2021; 11:2078. [PMID: 34829427 PMCID: PMC8623579 DOI: 10.3390/diagnostics11112078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 11/16/2022] Open
Abstract
To improve the early recognition of danger signs in children with severe febrile illness in low resource settings, WHO promotes automated respiratory rate (RR) counting, but its performance is unknown in this population. Therefore, we prospectively evaluated the field performance of automated point-of-care plethysmography-based RR counting in hospitalized children with severe febrile illness (<5 years) in DR Congo. A trained research nurse simultaneously counted the RR manually (comparative method) and automatically with the Masimo Rad G pulse oximeter. Valid paired RR measurements were obtained in 202 (83.1%) children, among whom 43.1% (87/202) had fast breathing according to WHO criteria based on manual counting. Automated counting frequently underestimated the RR (median difference of -1 breath/minute; p2.5-p97.5 limits of agreement: -34-6), particularly at higher RR. This resulted in a failure to detect fast breathing in 24.1% (21/87) of fast breathing children (positive percent agreement: 75.9%), which was not explained by clinical characteristics (p > 0.05). Children without fast breathing were mostly correctly classified (negative percent agreement: 98.3%). In conclusion, in the present setting the automated RR counter performed insufficiently to facilitate the early recognition of danger signs in children with severe febrile illness, given wide limits of agreement and a too low positive percent agreement.
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Affiliation(s)
- Bieke Tack
- Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
- Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
| | - Daniel Vita
- Hôpital Général de Référence Saint Luc de Kisantu, Kisantu, Democratic Republic of the Congo; (D.V.); (T.N.M.)
| | - Thomas Nsema Mbaki
- Hôpital Général de Référence Saint Luc de Kisantu, Kisantu, Democratic Republic of the Congo; (D.V.); (T.N.M.)
| | - Octavie Lunguya
- Department of Microbiology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo;
- Department of Medical Biology, University Teaching Hospital of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Jaan Toelen
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium;
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
- Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium
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Kano S, Yamamoto A, Ishikawa A, Fujii M. Respiratory rate on exercise measured by nanoparticle-based humidity sensor. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:3567-3570. [PMID: 31946649 DOI: 10.1109/embc.2019.8856875] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this study, we show the measurement of respiratory rate on exercise using a nanoparticle-based humidity sensor. A portable respiratory rate sensor is comprised of a colloidal silica nanoparticle-based humidity sensor chip. The impedance of the silica nanoparticle film is dependent on humidity and it is used for the detection of humid exhaled air. The respiratory rate sensor can be attached on an oxygen mask and the sensor signal is remotely monitored via Bluetooth. We show that the sensor follows a respiratory rate up to 60 bpm. We compare the sensor signal with that of a conventional respiratory measurement unit, which monitors a respiratory volume. The nanoparticle-based sensor can monitor a respiratory rate of an exercising person on a treadmill. The sensor operates stably for almost one year.
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Al-Halhouli A, Al-Ghussain L, El Bouri S, Liu H, Zheng D. Clinical evaluation of stretchable and wearable inkjet-printed strain gauge sensor for respiratory rate monitoring at different measurements locations. J Clin Monit Comput 2020; 35:453-462. [PMID: 32088910 DOI: 10.1007/s10877-020-00481-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 01/31/2020] [Indexed: 01/20/2023]
Abstract
The respiration rate (RR) is a vital sign in physiological measurement and clinical diagnosis. RR can be measured using stretchable and wearable strain gauge sensors which detect the respiratory movements in the abdomen or thorax areas caused by volumetric changes. In different body locations, the accuracy of RR detection might differ due to different respiratory movement amplitudes. Few studies have quantitatively investigated the effect of the measurement location on the accuracy of new sensors in RR detection. Using a stretchable and wearable inkjet-printed strain gauge (IPSG) sensor, RR was measured from five body locations (umbilicus, upper abdomen, xiphoid process, upper thorax, and diagonal) on 30 healthy test subjects while sitting on an armless chair. At each location, reference RR was simultaneously detected by the e-Health sensor, and the measurement was repeated twice. Subjects were asked about the comfortableness of locations. Based on Levene's test, ANOVA was performed to investigate if there is a significant difference in RR between sensors, measurement locations, and two repeated measurements. Bland-Altman analysis was applied to the RR measurements at different locations. The effects of measurement site and measurement trials on RR difference between sensors were also investigated. There was no significant difference between IPSG and reference sensors, between any locations, and between the two measurements (all p > 0.05). As to the RR deviation between IPSG and reference sensors, there was no significant difference between any locations, or between two measurements (all p > 0.05). All the 30 subjects agreed that diagonal and upper thorax positions were the most uncomfortable and most comfortable locations for measurement, respectively. The IPSG sensor could accurately detect RR at five different locations with good repeatability. Upper thorax was the most comfortable location.
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Affiliation(s)
- Ala'aldeen Al-Halhouli
- Mechatronics Engineering Department/NanoLab, School of Applied Technical Sciences, German Jordanian University, P.O. Box 35247, Amman, 11180, Jordan. .,Institute of Microtechnology, Technische Universität Braunschweig, Brunswick, Germany. .,Faculty of Engineering, Middle East University, Amman, 11831, Jordan.
| | - Loiy Al-Ghussain
- Mechatronics Engineering Department/NanoLab, School of Applied Technical Sciences, German Jordanian University, P.O. Box 35247, Amman, 11180, Jordan.,Mechanical Engineering Department, University of Kentucky, Lexington, KY, 40506, USA
| | - Saleem El Bouri
- Mechatronics Engineering Department/NanoLab, School of Applied Technical Sciences, German Jordanian University, P.O. Box 35247, Amman, 11180, Jordan
| | - Haipeng Liu
- Medical Device and Technology Research Laboratory, School of Allied Health, Faculty of Health, Education, Medicine and Social Care, Anglia Ruskin University, Chelmsford, CM1 1SQ, UK.,Research Centre of Intelligent Healthcare, Faculty of Health and Life Science, Coventry University, Coventry, CV1 5FB, UK
| | - Dingchang Zheng
- Research Centre of Intelligent Healthcare, Faculty of Health and Life Science, Coventry University, Coventry, CV1 5FB, UK
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Clinical Evaluation of Stretchable and Wearable Inkjet-Printed Strain Gauge Sensor for Respiratory Rate Monitoring at Different Body Postures. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10020480] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Respiratory rate (RR) is a vital sign with continuous, convenient, and accurate measurement which is difficult and still under investigation. The present study investigates and evaluates a stretchable and wearable inkjet-printed strain gauge sensor (IJP) to estimate the RR continuously by detecting the respiratory volume change in the chest area. As the volume change could cause different strain changes at different body postures, this study aims to investigate the accuracy of the IJP RR sensor at selected postures. The evaluation was performed twice on 15 healthy male subjects (mean ± SD of age: 24 ± 1.22 years). The RR was simultaneously measured in breaths per minute (BPM) by the IJP RR sensor and a reference RR sensor (e-Health nasal thermal sensor) at each of the five body postures namely standing, sitting at 90°, Flower’s position at 45°, supine, and right lateral recumbent. There was no significant difference in measured RR between IJP and reference sensors, between two trials, or between different body postures (all p > 0.05). Body posture did not have any significant effect on the difference of RR measurements between IJP and the reference sensors (difference <0.01 BPM for each measurement in both trials). The IJP sensor could accurately measure the RR at different body postures, which makes it a promising, simple, and user-friendly option for clinical and daily uses.
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Fabrication and Evaluation of a Novel Non-Invasive Stretchable and Wearable Respiratory Rate Sensor Based on Silver Nanoparticles Using Inkjet Printing Technology. Polymers (Basel) 2019; 11:polym11091518. [PMID: 31540494 PMCID: PMC6781180 DOI: 10.3390/polym11091518] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 02/08/2023] Open
Abstract
The respiration rate (RR) is a key vital sign that links to adverse clinical outcomes and has various important uses. However, RR signals have been neglected in many clinical practices for several reasons and it is still difficult to develop low-cost RR sensors for accurate, automated, and continuous measurement. This study aims to fabricate, develop and evaluate a novel stretchable and wearable RR sensor that is low-cost and easy to use. The sensor is fabricated using the soft lithography technique of polydimethylsiloxane substrates (PDMS) for the stretchable sensor body and inkjet printing technology for creating the conductive circuit by depositing the silver nanoparticles on top of the PDMS substrates. The inkjet-printed (IJP) PDMS-based sensor was developed to detect the inductance fluctuations caused by respiratory volumetric changes. The output signal was processed in a Wheatstone bridge circuit to derive the RR. Six different patterns for a IJP PDMS-based sensor were carefully designed and tested. Their sustainability (maximum strain during measurement) and durability (the ability to go bear axial cyclic strains) were investigated and compared on an automated mechanical stretcher. Their repeatability (output of the sensor in repeated tests under identical condition) and reproducibility (output of different sensors with the same design under identical condition) were investigated using a respiratory simulator. The selected optimal design pattern from the simulator evaluation was used in the fabrication of the IJP PDMS-based sensor where the accuracy was inspected by attaching it to 37 healthy human subjects (aged between 19 and 34 years, seven females) and compared with the reference values from e-Health nasal sensor. Only one design survived the inspection procedures where design #6 (array consists of two horseshoe lines) indicated the best sustainability and durability, and went through the repeatability and reproducibility tests. Based on the best pattern, the developed sensor accurately measured the simulated RR with an error rate of 0.46 ± 0.66 beats per minute (BPM, mean ± SD). On human subjects, the IJP PDMS-based sensor and the reference e-Health sensor showed the same RR value, without any observable differences. The performance of the sensor was accurate with no apparent error compared with the reference sensor. Considering its low cost, good mechanical property, simplicity, and accuracy, the IJP PDMS-based sensor is a promising technique for continuous and wearable RR monitoring, especially under low-resource conditions.
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Liu H, Allen J, Zheng D, Chen F. Recent development of respiratory rate measurement technologies. Physiol Meas 2019; 40:07TR01. [PMID: 31195383 DOI: 10.1088/1361-6579/ab299e] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Respiratory rate (RR) is an important physiological parameter whose abnormality has been regarded as an important indicator of serious illness. In order to make RR monitoring simple to perform, reliable and accurate, many different methods have been proposed for such automatic monitoring. According to the theory of respiratory rate extraction, methods are categorized into three modalities: extracting RR from other physiological signals, RR measurement based on respiratory movements, and RR measurement based on airflow. The merits and limitations of each method are highlighted and discussed. In addition, current works are summarized to suggest key directions for the development of future RR monitoring methodologies.
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Affiliation(s)
- Haipeng Liu
- Faculty of Health, Education, Medicine, and Social Care, Anglia Ruskin University, Chelmsford, CM1 1SQ, United Kingdom. Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
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Baker K, Alfvén T, Mucunguzi A, Wharton-Smith A, Dantzer E, Habte T, Matata L, Nanyumba D, Okwir M, Posada M, Sebsibe A, Nicholson J, Marasciulo M, Izadnegahdar R, Petzold M, Källander K. Performance of Four Respiratory Rate Counters to Support Community Health Workers to Detect the Symptoms of Pneumonia in Children in Low Resource Settings: A Prospective, Multicentre, Hospital-Based, Single-Blinded, Comparative Trial. EClinicalMedicine 2019; 12:20-30. [PMID: 31388660 PMCID: PMC6677646 DOI: 10.1016/j.eclinm.2019.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/09/2019] [Accepted: 05/28/2019] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Pneumonia is one of the leading causes of death in children under-five globally. The current diagnostic criteria for pneumonia are based on increased respiratory rate (RR) or chest in-drawing in children with cough and/or difficulty breathing. Accurately counting RR is difficult for community health workers (CHWs). Current RR counting devices are frequently inadequate or unavailable. This study analysed the performance of improved RR timers for detection of pneumonia symptoms in low-resource settings. METHODS Four RR timers were evaluated on 454 children, aged from 0 to 59 months with cough and/or difficulty breathing, over three months, by CHWs in hospital settings in Cambodia, Ethiopia, South Sudan and Uganda. The devices were the Mark Two ARI timer (MK2 ARI), counting beads with ARI timer, Rrate Android phone and the Respirometer feature phone applications. Performance was evaluated for agreement with an automated RR reference standard (Masimo Root patient monitoring and connectivity platform with ISA CO2 capnography). This study is registered with ANZCTR [ACTRN12615000348550]. FINDINGS While most CHWs managed to achieve a RR count with the four devices, the agreement was low for all; the mean difference of RR measurements from the reference standard for the four devices ranged from 0.5 (95% C.I. - 2.2 to 1.2) for the respirometer to 5.5 (95% C.I. 3.2 to 7.8) for Rrate. Performance was consistently lower for young infants (0 to < 2 months) than for older children (2 to ≤ 59 months). Agreement of RR classification into fast and normal breathing was moderate across all four devices, with Cohen's Kappa statistics ranging from 0.41 (SE 0.04) to 0.49 (SE 0.05). INTERPRETATION None of the four devices evaluated performed well based on agreement with the reference standard. The ARI timer currently recommended for use by CHWs should only be replaced by more expensive, equally performing, automated RR devices when aspects such as usability and duration of the device significantly improve the patient-provider experience. FUNDING Bill & Melinda Gates Foundation [OPP1054367].
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Affiliation(s)
- Kevin Baker
- Malaria Consortium, London, United Kingdom
- Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
- Corresponding author at: Malaria Consortium, The Green House, 244-254 Cambridge Heath Road, London E2 9DA, United Kingdom.
| | - Tobias Alfvén
- Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
- Sachs' Children and Youth Hospital, Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | | | | | | | | - Max Petzold
- Gothenburg University, Gothenburg, Sweden
- University of the Witwatersrand, Johannesburg, South Africa
| | - Karin Källander
- Malaria Consortium, London, United Kingdom
- Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
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