A portable forced oscillation device for respiratory home monitoring

Rigau, Jordi; Farre, R.; Roca, Josep; Marco, S.; Herms, A; Navajas, Daniel

doi:10.1183/09031936.02.00642001

Cited by 23 publications

(21 citation statements)

References 21 publications

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“…Since minimal patient cooperation is required, FOT could be a suitable tool for the routine home monitoring of airway obstruction in asthmatic patients [9,10]. This application is currently possible by using a recently designed portable FOT device [11]. Nevertheless, as FOT measurements are usually carried out by a technician in the lung function lab, there are no data currently available on the feasibility of unsupervised FOT self-measurement at the patient9s home.…”

mentioning

confidence: 99%

Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home

Rigau

Burgos²,

García-Hernández³

et al. 2003

Eur Respir J

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As active patient cooperation is not required, the forced oscillation technique (FOT) could be suitable for measuring airway obstruction in routine home applications. Nevertheless, FOT has never been used at the patient9s home to date. The aim of this study was to assess the feasibility of FOT and the reproducibility of measured respiratory resistance (Rrs) in routine patient self-testing at home.Altogether, nine asthmatic patients self-measured their Rrs with a portable FOT device and spirometry for 10-14 days, in the morning and evening, and before and after bronchodilator inhalation. During each measurement session, the patients carried out four consecutive FOT measurements. Grubbs9 discordancy test for detecting outliers was used to evaluate intermeasure reliability.Only 4.9% of Rrs data reported by patients were rejected as artefacts. The coefficient of variation of Rrs was 7.9¡6.3% (mean¡SD). When compared with spirometry, the per cent change in Rrs for detecting a positive bronchodilator response showed an 83% sensitivity and 72% specificity.Unsupervised self-measurement of respiratory resistance at the patient9s home provided results similar to those obtained by a technician in a lung function lab. Forced oscillation technique could be a useful tool for the routine follow-up of asthmatic patients at home. Eur Respir J 2003; 22: 668-671.

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confidence: 99%

Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home

Rigau

Burgos²,

García-Hernández³

et al. 2003

Eur Respir J

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“…First, given that 5-Hz sinusoidal oscillation can be easily incorporated into noninvasive mechanical ventilators [16], it could be possible to assess whether a ventilated patient is experiencing EFL and to modify the ventilator settings to improve ventilation. Second, it has been recently reported that a 5-Hz sinusoidal FOT can be implemented in a portable device [17] allowing the patient to self-assess their impedance at home [18]. Accordingly, application of the method proposed by DELLACÀ et al [9] in this setting could allow an easy monitoring of EFL in COPD patients at home.…”

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confidence: 99%

Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach

Farré¹,

Navajas²

2004

Eur Respir J

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Patients with severe chronic obstructive pulmonary disease (COPD) usually experience expiratory flow limitation (EFL) during spontaneous breathing at rest [1]. As EFL reduces the effectiveness of expiration, it results in dynamic hyperinflation with consequent dyspnoea, which is one of the major complaints of patients with COPD. In these patients, the consequences of EFL are markedly increased during exercise [2]. Bearing in mind that EFL is a good predictor of dyspnoea in COPD patients [3,4], simple methods for detecting EFL without perturbing normal breathing are of clinical interest. In 1995 KOULOURIS et al. [5] proposed a method to detect EFL based on the external application of a negative pressure at the mouth during tidal expiration (negative expiratory pressure (NEP)). EFL is detected by comparing the magnitude of expiratory flow before and after application of NEP: in case of EFL, the expiratory flow does not rise when increasing the driving pressure. More recently, NINANE et al.[6] proposed the estimation of EFL during spontaneous breathing with a similar approach. To increase the driving pressure during expiration, these authors applied a positive abdominal pressure by manual compression of the patient9s abdominal wall. When compared with the NEP technique, this approach has the advantage of instrumental simplicity, but suffers from the drawbacks of applying abdominal pressure of uncontrolled magnitude and lack of automatisation. Both procedures can be applied during breathing at rest as well as during exercise [7,8].In this issue of the European Respiratory Journal (ERJ), DELLACÀ et al.[9] present interesting novel data showing that the forced oscillation technique (FOT) can be useful for noninvasively detecting EFL during spontaneous breathing. The FOT, which was proposed in the 1950s [10], is based on applying a small-amplitude oscillation pressure at the mouth. Using the FOT the patient9s respiratory mechanics can be determined by simply recording the oscillatory pressure and flow signals at the mouth, provided that the oscillation frequency is much higher than the breathing rate. The relationship between the pressure and the flow oscillation is the impedance of the respiratory system, which has two components: respiratory resistance (Rrs) and reactance (Xrs). In a simple interpretation, Rrs is attributed to airways and tissue resistances, whereas Xrs is determined by the inertial and compliant properties of the respiratory system. The rationale of using FOT for assessing EFL is that under this flow regime the forced oscillation applied at the mouth cannot reach the alveoli given the fact that the choke point shifts upstream of the lung during EFL. Therefore, the effective impedance viewed from the FOT device corresponds to only a fraction of the respiratory system: from the mouth to the choke point. According to this hypothesis, the associated decrease in the effective respiratory compliance results in a reduction of the measured Xrs during expiration when compared with the non flow-limited inspi...

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“…However, the implementation of telemedicine services using FOT depends on the development of a dedicated instrument and protocol. Rigau et al (2002) were the first to describe a portable FOT system for home care applications. The system allowed the online computation of Rrs and Xrs and of reliability indices at 5 Hz.…”

Section: Forced Oscillation In Telemedicinementioning

confidence: 99%

Forced Oscillation Technique in the Detection of Smoking-Induced Respiratory Changes

Faria¹,

Silva²,

Costa³

et al. 2012

Biomedical Engineering - Technical Applications in Medicine

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A portable forced oscillation device for respiratory home monitoring

Cited by 23 publications

References 21 publications

Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home

Unsupervised self-testing of airway obstruction by forced oscillation at the patient's home

Assessment of expiratory flow limitation in chronic obstructive pulmonary disease: a new approach

Forced Oscillation Technique in the Detection of Smoking-Induced Respiratory Changes

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