Accuracy of respiratory inductive plethysmography during wakefulness and sleep in patients with obstructive sleep apnea

Laboratoire d'Explorations Fonctionelles Respiratoire, Hospital Antoine Beclere, INSERM CJF 8909 Clamart, France.
Chest (Impact Factor: 7.48). 10/1992; 102(4):1145-51. DOI: 10.1378/chest.102.4.1145
Source: PubMed


To assess the accuracy of the respiratory inductive plethysmograph (RIP) during sleep in obese patients with obstructive sleep apnea (OSA), we monitored 13 patients with OSA during wakefulness and nocturnal sleep with simultaneous measurements of tidal volume from RIP and integrated airflow. Patients wore a tightly fitting face mask with pneumotachograph during wakefulness and sleep. Calibrations were performed during wakefulness prior to sleep and compared with subsequent wakeful calibrations at the end of the study. Patients maintained the same posture during sleep (supine, 11; lateral, two) as during calibrations. There were no significant differences in calibrations before sleep and after awakening. The mean error in 13 patients undergoing RIP measurements of tidal volume during wakefulness was -0.7 +/- 3.4 percent while that during sleep was 2.1 +/- 14.9 percent (p < 0.001). The standard deviation (SD) of the differences between individual breaths measured by RIP and integrated airflow was 9.8 +/- 5.5 percent during wakefulness and 25.5 +/- 18.6 percent during sleep (p < 0.001). During both wakefulness and sleep, errors in RIP tidal volume were not significantly correlated with body mass index. In 12 patients with at least 10 percent time in each of stages 1 and 2 sleep, SD was greater in stage 2 sleep compared with wakefulness and stage 1 (p < 0.001). In three patients who manifested all stages of sleep, SD was greater in REM sleep than in wakefulness and all stages of non-REM sleep (p < 0.001). In three patients who manifested all stages of sleep, SD was greater in REM sleep than in wakefulness and all stages of non REM sleep (p < 0.001). This was associated with paradoxic motion of the rib cage in two patients during REM. We conclude that, despite increased errors in individual breath measurements during sleep, more marked during stages 2 and REM sleep, RIP is clinically useful to measure ventilation quantitatively in obese patients with sleep apnea. The criterion of a decrease of 50 percent in tidal volume assessed by RIP is appropriate to define hypopneas in such patients.

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Available from: Pierre Escourrou, Jan 07, 2015
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    • "Non-invasive ventilation monitoring is desirable for ambulatory physiological monitoring systems, and accurate ventilation monitoring can offer detail information about respiratory disorder, such as sleep apnea, COPD, and asthma etc. Performance tests showed this RIP module can acquire accurate Vt measurement after QDC calibration. Some scholars have doubted the reliability of long-term ventilation monitoring by the calibrated RIP method, as the chest and abdominal contribution to ventilation may be different with changes of body posture [21], so for a wearable monitoring system with RIP sensors for ventilation estimation, one of the critical problems is how to keep the estimation of ventilation within an acceptable level when posture changes in real life. Posture-related calibration is a method which has been put forward recently, where acceleration sensor is used for posture identification [22]. "
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    ABSTRACT: In this paper, we present an RIP module with the features of supporting multiple inductive sensors, no variable frequency LC oscillator, low power consumption, and automatic gain adjustment for each channel. Based on the method of inductance measurement without using a variable frequency LC oscillator, we further integrate pulse amplitude modulation and time division multiplexing scheme into a module to support multiple RIP sensors. All inductive sensors are excited by a high-frequency electric current periodically and momentarily, and the inductance of each sensor is measured during the time when the electric current is fed to it. To improve the amplitude response of the RIP sensors, we optimize the sensing unit with a matching capacitor parallel with each RIP sensor forming a frequency selection filter. Performance tests on the linearity of the output with cross-sectional area and the accuracy of respiratory volume estimation demonstrate good linearity and accurate lung volume estimation. Power consumption of this new RIP module with two sensors is very low. The performance of respiration measurement during movement is also evaluated. This RIP module is especially desirable for wearable systems with multiple RIP sensors for long-term respiration monitoring.
    Full-text · Article · Dec 2012 · Sensors
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    • "RIP has been used extensively to assess apnea and breathing patterns during sleep in humans20,21,23,24,26 and animals.45 Multiple human studies have demonstrated correlations among TAA, bronchoconstriction, and bronchodilation.15,25,44 "
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    ABSTRACT: Nocturnal bronchoconstriction is a common symptom of asthma in humans, but is poorly documented in animal models. Thoracoabdominal asynchrony (TAA) is a noninvasive clinical indication of airway obstruction. In this study, respiratory inductive plethysmography (RIP) was used to document nocturnal TAA in house dust mite (HDM)-sensitive Cynomolgus macaques. Dynamic compliance (C(dyn)) and lung resistance (R(L)) measured in anesthetized animals at rest and following exposure to HDM allergen, methacholine, and albuterol were highly correlated with three RIP parameters associated with TAA, ie, phase angle of the rib cage and abdomen waveforms (PhAng), baseline effort phase relation (eBPRL) and effort phase relation (ePhRL). Twenty-one allergic subjects were challenged with HDM early in the morning, and eBPRL and ePhRL were monitored for 20 hours after provocation. Fifteen of the allergic subjects exhibited gradual increases in eBPRL and ePhRL between midnight and 6 am, with peak activity at 4 am. However, as in humans, this nocturnal response was highly variable both between subjects and within subjects over time. The results document that TAA in this nonhuman primate model of asthma is highly correlated with C(dyn) and R(L), and demonstrate that animals exhibiting acute responses to allergen exposure during the day also exhibit nocturnal TAA.
    Full-text · Article · Jul 2010 · Journal of Asthma and Allergy
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    • "Bands should be taped firmly to the skin to avoid slippage during overnight monitoring. Sleep-related thoracoabdominal distortion or movement asynchrony also can affect accuracy of RIP measurements during sleep [26] [27]. "
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    ABSTRACT: Monitoring of respiration during sleep allows the assessment of physiologic variables that are required to characterize SRBD events. The patency of the upper airway, the pattern of breathing, oxygenation, and ventilation usually can be inferred from simultaneous measurements of airflow, respiratory effort, thoracic volume, and blood gases. As new techniques of respiratory monitoring emerge, the respiratory therapist and sleep technologist must be familiar with the advantages and shortcomings of each modality.
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