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: 7.13). 10/1992; 102(4):1145-51. DOI: 10.1378/chest.102.4.1145
Source: PubMed

ABSTRACT 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Validation of respiratory inductive plethysmography (LifeShirt system) (RIPLS) for tidal volume (VT), minute ventilation (V˙E), and respiratory frequency (ƒB) was performed among people with untreated obesity hypoventilation syndrome (OHS) and controls. Measures were obtained simultaneously from RIPLS and a spirometer during two tests, and compared using Bland Altman analysis. Among 13 OHS participants (162 paired measures), RIPLS-spirometer agreement was unacceptable for VT: mean difference (MD) 3mL (3%); limits of agreement (LOA) -216 to 220mL (±36%); V˙E: MD 0.1L.min(-1) (2%); LOA -4.1 to 4.3L.min(-1) (±36%); and ƒB: MD 0.2br.min(-1) (2%); LOA -4.6 to 5.0br.min(-1) (±27%). Among 13 controls (197 paired measures), RIPLS-spirometer agreement was acceptable for ƒB: MD -0.1br.min(-1) (-1%); LOA -1.2 to 1.1br.min(-1) (±12%), but unacceptable for VT: MD 5mL (1%); LOA -160 to 169mL (±20%) and V˙E: MD 0.1L.min(-1) (2%); LOA -1.4 to 1.5L.min(-1) (±20%). RIPLS produces valid measures of ƒB among controls but not OHS patients, and is not valid for quantifying respiratory volumes among either group.
    Respiratory Physiology & Neurobiology 01/2014; DOI:10.1016/j.resp.2014.01.014 · 1.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Impedance pneumography is a technique which allows the monitoring of respiratory activity through the measurement of variations in the impedance between two points located on the thoracic surface. In this paper, a low-cost, easily portable, and re- configurable measurement system is presented, suitable to perform impedance pneumography investigations. The system is based on a LabVIEW virtual instrument and employs only a data acquisition card. A preliminary metrological assessment of the system is performed, showing that the basic accuracy of the instrument is adequate for monitoring patients lying in a bed. Acquisitions made on several volunteers have evidenced the feasibility of the proposed system in monitoring the breath activity of a patient and in extrapolating the relevant diagnostic parameters. With the aid of suitable signal processing and hardware optimizations the instrument might become a truly portable and non-invasive breath rate monitoring system.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IntroductionSleep in intensive care unit (ICU) patients is severely altered. In a large proportion of critically ill patients, conventional sleep electroencephalogram (EEG) patterns are replaced by atypical sleep. On the other hand, some non-sedated patients can display usual sleep EEG patterns. In the latter, sleep is highly fragmented and disrupted and conventional rules may not be optimal. We sought to determine whether sleep continuity could be a useful metric to quantify the amount of sleep with recuperative function in critically ill patients with usual sleep EEG features.Methods We retrospectively reanalyzed polysomnographies recorded in non-sedated critically ill patients requiring non-invasive ventilation (NIV) for acute hypercapnic respiratory failure. Using conventional rules, we built two-state hypnograms (sleep and wake) and identified all sleep episodes. The percentage of time spent in sleep bouts (<10 min), short naps (>10 and <30 min) and long naps (>30 min) was used to describe sleep continuity. In a first study, we compared these measures regarding good (NIV success) or poor outcome (NIV failure). In a second study performed on a different patient group, we compared these measurements during NIV and during spontaneous breathing.ResultsWhile fragmentation indices were similar in the two groups, the percentage of total sleep time spent in short naps was higher and the percentage of sleep time spent in sleep bouts was lower in patients with successful NIV. The percentage of total sleep time spent in long naps was higher and the percentage of sleep time spent in sleep bouts was lower during NIV than during spontaneous breathing; the level of reproducibility of sleep continuity measures between scorers was high.Conclusion Sleep continuity measurements could constitute a clinically relevant and reproducible assessment of sleep disruption in non-sedated ICU patients with usual sleep EEG.
    Critical care (London, England) 11/2014; 18(6):628. DOI:10.1186/s13054-014-0628-4

Full-text (2 Sources)

Available from
Jan 7, 2015