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Awake flow limitation with negative expiratory pressure in sleep disordered breathing
R Tamisier1, B Wuyam, I Nicolle
1Service de Pneumologie, CHU Nice, France. rtamisie@bidmc.harvard.edu
Sleep Medicine
|April 28, 2005
Summary
Negative expiratory pressure (NEP) flow-volume curves can help detect upper airway collapsibility (UAC) and anticipate sleep-disordered breathing (SDB) severity. This method shows promise for identifying SDB in awake individuals.
Area of Science:
- Respiratory Physiology
- Sleep Medicine
- Pulmonary Diagnostics
Background:
- Upper airway collapsibility (UAC) is theoretically linked to sleep-disordered breathing (SDB) severity.
- Current inspiratory UAC measurements show poor correlation with obstructive sleep apnea (OSA) severity.
Purpose of the Study:
- To investigate negative expiratory pressure (NEP) as a technique to anticipate SDB severity in awake subjects.
- To characterize flow-volume curves and develop a quantitative NEP index.
Main Methods:
- Evaluated 15 healthy and 35 SDB subjects in sitting and supine positions.
- Measured flow-volume curves and a novel NEP quantitative index (NEP loop area / spontaneous loop area) at -5 and -10 cm H2O.
- Assessed correlation with SDB severity, adjusting for age, BMI, and ERV.
Main Results:
- Abnormal flow-volume curves were more frequent in SDB patients, particularly in sitting posture and supine at -10 cm H2O.
- The NEP quantitative index decreased with increasing SDB severity, independent of confounding factors.
- Specific thresholds for the NEP index effectively identified SDB patients and controls in supine position.
Conclusions:
- NEP flow-volume curves and the quantitative index are effective for detecting UAC in awake individuals.
- These findings suggest NEP is a valuable tool for anticipating SDB severity.
- Further prospective studies in the general population are recommended for confirmation.