Assessment of Airflow Obstruction during CPAP by Means of Forced Oscillation in Patients with  Sleep Apnea

Navajas, Daniel; Farré, Ramón; Rotger, M.; BADIA, R; PUIG-de-MORALES, Marina; Montserrat, Josep M.

doi:10.1164/ajrccm.157.5.9710026

Cited by 85 publications

(69 citation statements)

References 17 publications

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“…Frequency analysis of the EEG signal was carried out and no evidence of neurological activation was found. These findings are consistent with the clinical experience with FOT [3][4][5]. Significant effects on the upper airway or the EEG produced by the use of FOT, with and without CPAP, were not observed in subjects with SAHS.…”

Section: Discussionsupporting

confidence: 89%

“…The oscillating pressure stimulus was a pressure wave generated with the same basic setting that the present group has described in FOT guided CPAP titration studies [1][2][3]. This setting allowed the application of a CPAP device to normalize sleep variables.…”

Section: Stimulusmentioning

confidence: 99%

“…13 The forced oscillation technique (FOT) is a simple and noninvasive method that allows continuous online monitoring of airflow obstruction during sleep, even in the absence of flow, as occurs in apnoeas. FOT has been applied in clinical diagnostic studies in patients with sleep apnoea/hypopnoea syndrome (SAHS) [1][2][3][4] and in continuous positive airway pressure (CPAP) titration studies [5,6] with highly encouraging results.…”

mentioning

confidence: 99%

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Forced oscillation measurements do not affect upper airway muscle tone or sleep in clinical studies

et al. 2001

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Upper airway obstruction in the sleep apnoea/hypopnoea syndrome (SAHS) can be easily assessed by measuring respiratory impedance with the forced oscillation technique (FOT). This methodology has been proposed as a useful clinical tool both for the diagnosis of sleep breathing disorders and for continuous positive airway pressure (CPAP) titration. However, previous studies suggest that the application of high-frequency pressure oscillation to the upper airway may induce changes in the electroencephalogram (EEG) or upper airway muscle function. The effect of FOT measurements on upper airway muscle tone and EEG in clinical sleep studies was examined. Seven patients with moderate SAHS were included (age: 54 ¡ 11 yrs; apnoea/hypopnoea index: 43 ¡ 21 events?h -1 ; body mass index: 30 ¡ 2 kg?m -2 ). Genioglossus surface electromyogram activity (EMGgg) and EEG signal were analysed with and without FOT application (frequency: 5 Hz and 30 Hz; peak-topeak pressure oscillation: 1 cmH 2 O) during stable sleep. Measurements were carried out in two different situations.Step 1: applying FOT during episodes of obstructive events or flow limitation; and step 2: during prolonged periods of normal breathing at optimal CPAP. The root mean square of EMGgg activity and fast Fourier analysis (alpha and delta bands) of the EEG signal were performed.The application of FOT did not increase EMGgg activity in any of the situations studied. In addition, no evidence of the effects on EEG was found: alpha/delta relationship: awake:0.70, baseline sleep:0.13, FOT(5 Hz):0.18, FOT(30 Hz):0.11.The presented results suggest that the use of forced oscillation technique over the ranges of frequency and amplitude proposed for clinical sleep studies does not induce changes in upper airway muscle activity and neurological variables in patients with sleep apnoea/hypopnoea syndrome.

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Section: Discussionsupporting

confidence: 89%

Section: Stimulusmentioning

confidence: 99%

mentioning

confidence: 99%

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Forced oscillation measurements do not affect upper airway muscle tone or sleep in clinical studies

et al. 2001

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“…The circuit designed for analog real-time computation of respiratory mechanical impedance was practically tested by using real signals recorded in patients [6]. The study was carried out during CPAP titration with full polysomnography on six male patients with OSA.…”

Section: Assessment In Sleep Studiesmentioning

confidence: 99%

“…The FOT has been widely used to measure Z in a variety of clinical fields such as bronchoconstriction [2] and brochodilation [3] tests, anesthesia [4], and intensive care [5]. As has been shown recently [6], [7], [8], FOT is also useful in assessing inspiratory and expiratory airway obstruction in the recurrent upper-airway collapses found in patients with obstructive sleep apnea/hypopnea (OSA).…”

Section: Introductionmentioning

confidence: 99%

Analog circuit for real-time computation of respiratory mechanical impedance in sleep studies

Farré

Rotger

Montserrat³

et al. 1997

IEEE Trans. Biomed. Eng.

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Abstract-The aim of this work was to develop a low-cost circuit for real-time analog computation of the respiratory mechanical impedance in sleep studies. The practical performance of the circuit was tested in six patients with obstructive sleep apnea. The impedance signal provided by the analog circuit was compared with the impedance calculated simultaneously with a conventional computerized system. We concluded that the low-cost analog circuit developed could be a useful tool for facilitating the real-time assessment of airway obstruction in routine sleep studies.

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Upper Airway Mechanics

Badr

Rowley

2006

Wiley Encyclopedia of Biomedical Engineering

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Understanding the mechanics of the upper airway is critical to the research on the pathophysiology of upper airway obstruction. This article will review the determinants of upper airway patency including the upper airway dilating muscles, the transmural pressure across the airway, pharyngeal compliance, and craniofacial structure. During sleep, loss of the wakefulness stimulus to breathe results in decreased upper airway caliber and increased resistance. Models that characterize the relationship between pressure and flow of the upper airway during sleep and that explain upper airway collapsibility during sleep will be presented. Finally, a proposed scheme of the pathophysiology of upper airway collapse during sleep will be presented.

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Assessment of Airflow Obstruction during CPAP by Means of Forced Oscillation in Patients with Sleep Apnea

Cited by 85 publications

References 17 publications

Forced oscillation measurements do not affect upper airway muscle tone or sleep in clinical studies

Forced oscillation measurements do not affect upper airway muscle tone or sleep in clinical studies

Analog circuit for real-time computation of respiratory mechanical impedance in sleep studies

Upper Airway Mechanics

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