Chest
Clinical Investigations SLEEPA New Method of Negative Expiratory Pressure Test Analysis Detecting Upper Airway Flow Limitation To Reveal Obstructive Sleep Apnea
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Materials and Methods
Thirty-seven male subjects referred to our sleep laboratory for suspected OSA syndrome after evaluation of spirometry to exclude subjects with bronchial obstruction were recruited for the study. Mean ± SD age was 46 ± 11 years, and mean body mass index (BMI) was 34 ± 7 kg/m2. None of the subjects had acute or known chronic cardiopulmonary or neuromuscular diseases. Each patient gave informed consent, and the study protocol was approved by the local scientific committee. All subjects underwent
Results
All subjects had normal forced expiratory flow volume loops (FVC and FEV1 of 101 ± 12% of predicted and 100 ± 12% of predicted, respectively). Nocturnal monitoring showed an AHI of 51 ± 32 events/h in the whole population studied. Most subjects were obese (BMI range, 27 to 59 kg/m2), and 10 of them had BMI > 35 kg/m2. Table 1 shows anthropometric and respiratory characteristics of subjects with BMI < 35 kg/m2 and with BMI > 35 kg/m2.
NEP application during tidal expiration produced an
Discussion
The main finding of the present study is that, to assess upper airway flow limitation in a population attending a sleep center for suspected OSA, the NEP test is more usefully evaluated by Δ (% peak) than by EFL (%Vt). In fact, Δ (% peak) was better correlated to AHI than EFL (%Vt). In addition, Δ (% peak) was always correlated with AHI in the group with BMI < 35 kg/m2, while EFL (%Vt) showed some correlations with AHI, mostly when severely obese
Acknowledgment
The authors wish to thank Dr. Pietro Abate for his help and Mr. Giovanni Sciortino for technical support.
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This study was supported by the Italian National Research Council.
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