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Am J Respir Crit Care Med. 2007 Apr 1;175(7):726-30. Epub 2007 Jan 11.

Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea.

Author information

1
Centre for Sleep Health and Research, Department of Respiratory Medicine, Royal North Shore Hospital, University of Sydney, Sydney, Australia.

Abstract

BACKGROUND:

It has been recognized that mandibular advancement splint (MAS) treatment is effective in some, but not all, patients with obstructive sleep apnea (OSA). Hence there is a need for a simple and reliable clinical tool to assist in the differentiation of treatment responses. We hypothesized that abnormalities of flow-volume curves, together with other clinical variables, may have clinical utility in the prediction of MAS treatment outcome.

METHODS:

Fifty-four patients with known OSA underwent MAS treatment. Expiratory and inspiratory flow-volume curves were measured in the erect and supine positions to derive midinspiratory flow (MIF(50)) and the ratio of expiratory to inspiratory flow at 50% of vital capacity (MEF(50):MIF(50)). Multivariable logistic regression was performed to identify additional significant clinical variables in the prediction of treatment outcome.

RESULTS:

The mean (+/- SD) apnea-hypopnea index (AHI) in 35 responders was significantly reduced from 28.9 +/- 13.7 to 6.7 +/- 5.8/hour (p<0.001). In 19 nonresponders there was no significant change in AHI. MIF(50) was lower (6.04 +/- 1.80 vs. 6.88 +/- 1.08 L/second; p=0.035) and the MEF(50):MIF(50) ratio was higher (0.82 +/- 0.23 vs. 0.61 +/- 0.15; p=0.001) in responders than nonresponders. Logistic regression analysis revealed that the MEF(50):MIF(50) ratio was the most important predictive factor for MAS treatment outcome, but that body mass index, age, and baseline AHI were also contributory.

CONCLUSIONS:

These data suggest that flow-volume curves, in combination with other factors such as body mass index, age, and baseline AHI, may have a useful clinical role in the prediction of treatment outcome with MAS.

PMID:
17218619
DOI:
10.1164/rccm.200608-1205OC
[Indexed for MEDLINE]

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