Turbine spirometers metrological support

308

236

There is an ever-growing demand for measuring respiratory variables during a variety of applications, including monitoring in clinical and occupational settings, and during sporting activities and exercise. Special attention is devoted to the monitoring of respiratory rate because it is a vital sign, which responds to a variety of stressors. There are different methods for measuring respiratory rate, which can be classed as contact-based or contactless. The present paper provides an overview of the currently available contact-based methods for measuring respiratory rate. For these methods, the sensing element (or part of the instrument containing it) is attached to the subject’s body. Methods based upon the recording of respiratory airflow, sounds, air temperature, air humidity, air components, chest wall movements, and modulation of the cardiac activity are presented. Working principles, metrological characteristics, and applications in the respiratory monitoring field are presented to explore potential development and applicability for each method.

Section: Techniques Based On Respiratory Airflowmentioning

confidence: 99%

Section: Techniques Based On Respiratory Airflowmentioning

confidence: 99%

Contact-Based Methods for Measuring Respiratory Rate

Massaroni

Nicolò

Presti

et al. 2019

308

236

“…Earlier studies typically used complex and bulky systems to measure expiratory airflow such as the Otis-McKerrow valve-Fleisch pneumotachograph–Validyne manometer setting in [ 3 ]. Currently, most commonly used devices for respiratory evaluation are hand-held or stationary devices such as the pneumotachometer-type spirometer shown in Figure 1 a or the turbine-type spirometer [ 18 ] in Figure 1 b.…”

Section: Background and State-of-the-artmentioning

confidence: 99%

Accurate Spirometry with Integrated Barometric Sensors in Face-Worn Garments

Zhou

Costa

Lukowicz

2020

Cardiorespiratory (CR) signals are crucial vital signs for fitness condition tracking, medical diagnosis, and athlete performance evaluation. Monitoring such signals in real-life settings is among the most widespread applications of wearable computing. We investigate how miniaturized barometers can be used to perform accurate spirometry in a wearable system that is built on off-the-shelf training masks often used by athletes as a training aid. We perform an evaluation where differential barometric pressure sensors are compared concurrently with a digital spirometer, during an experimental setting of clinical forced vital capacity (FVC) test procedures with 20 participants. The relationship between the two instruments is derived by mathematical modeling first, then by various regression methods from experiment data. The results show that the error of FVC vital values between the two instruments can be as low as 2∼3%. Beyond clinical tests, the method can also measure continuous tidal breathing air volumes with a 1∼3% error margin. Overall, we conclude that barometers with millimeter footprints embedded in face mask apparel can perform similarly to a digital spirometer to monitor breathing airflow and volume in pulmonary function tests.

“…The Lilly type sensing unit uses a flow restrictor to create a linear flow/differential pressure relationship at both sides of the restrictor immediately when the air flow travels through it (see Figure 2) according to the Poiseuille’s law:Δ P = Q R . Here, Q is the flow rate, R is the flow resistance, Δ P is the pressure difference. Its performance is well understood, and in comparison with other types of flowmeters such as turbine [10], Hot-wire [14], ultrasonic [13], Pitot tube [20] and Venturi tube types [12], it is simpler to make and cheaper, containing no moving parts but with a satisfactory accuracy.…”

Section: System Designmentioning

confidence: 99%

“…At their early stage, portable or handheld spirometer mainly took the forms of Wright and turbine peak flow meters [9,10]. Most of them were just able to perform simple peak expiratory flow test, and have low accuracy owing to the momentum and resistance errors associated with the moving parts such as windmills or flow valves in these kinds of equipment.…”

Section: Introductionmentioning

confidence: 99%

A Smart Phone Based Handheld Wireless Spirometer with Functions and Precision Comparable to Laboratory Spirometers

Zhou¹,

Yang²,

Huang³

2019

We report a smart phone based handheld wireless spirometer which uses a Lilly type sensing flowhead for respiratory signal acquisition and transmits the data to smartphone or other mobile terminals with Bluetooth signal transmission for data processing and result display. The developed spirometer was demonstrated to be able to detect flow rates ranging from 0–15 L/s with an accuracy of 4 mL/s, and can perform tests of flow volume (FV), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), etc. By having the functions and precision comparable to laboratory spirometers, it satisfies the American Thoracic Society and European Respiratory Society (ATS/ERS) proposed performance requirements for spirometer. At the same time, it is low cost, light and handy, low power consumption battery-powered. The test of 12 cases of subjects using the developed spirometer also indicated that it was easy to use for both providers and patients, and suitable for the Point of Care Test (POCT) of chronic obstructive pulmonary disease (COPD) and asthma at general-practice settings and homes.