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Flow-Volume Curve Abnormalities and Obstructive Sleep Apnea Syndrome

1985; Elsevier BV; Volume: 87; Issue: 2 Linguagem: Inglês

10.1378/chest.87.2.163

1931-3543

J Krieger, E Weitzenblum, André Vandevenne, Jean-Luc Stierle, D Kurtz,

Respiratory Support and Mechanisms

It has been suggested recently that flow-volume curves might be of interest in the diagnosis of obstructive sleep apnea syndromes (O-SAS) by demonstrating in the awake individual the presence of abnormalities related to modifications of the extrathoracic upper airways. Two different signs have been reported as being strongly related to O-SAS. The first sign is an increase in the ratio of forced expiratory flow to forced inspiratory flow at 50 percent of vital capacity (FEF50/FIF50), this ratio being greater than one. This sign, which is considered to be related to upper airway obstruction, was present in 44 percent of 27 O-SAS patients and only in 8 percent of 25 non-O-SAS patients. 1 Haponik E.F. Bleecker E.R. Allen R.P. Smith P.L. Kaplan J. Abnormal inspiratory flow-volume curves in patients with sleep disordered breathing. Am Rev Respir Dis. 1981; 124: 571-574 PubMed Google Scholar The second sign is “the sawtooth sign,” which consists of regular oscillations occurring at constant intervals on the forced expiratory or forced inspiratory flow-volume tracing, 2 Sanders M.H. Martin R.J. Pennock B.E. Rogers R.M. The detection of sleep apnea in the awake patient: the “saw-tooth” sign. JAMA. 1981; 245: 2414-2418 Crossref PubMed Scopus (55) Google Scholar and is supposed to reflect fluttering of upper airway tissue; this sign was present in 85 percent of 13 O-SAS patients and in none of eight non-O-SAS subjects. When the two signs were combined, 75 percent of 16 O-SAS patients were found to have at least one abnormal sign 3 Chaudhary B.A. Elguindi A.S. Giacomini K. Speir W.A. Diagnosis of sleep apnea by flow-volume loops. Am Rev Respir Dis. 1982; 125: 101 Google Scholar while none of eight non-O-SAS patients had an abnormal flow-volume curve, suggesting that flow-volume curve abnormalities could be very highly specific for O-SAS. However, more recent studies found abnormal flow-volume curves in three out of seven 4 Tammelin B.R. Wilson A.F. de Berry Borowiecki B Sassin J.F. Flow-volume curves reflect pharyngeal airway abnormalities in sleep apnea syndrome. Am Rev Respir Dis. 1983; 128: 712-715 PubMed Google Scholar and in one out of five 5 Riley R.I. Guilleminault C. Herran J. Powell N. Cephalometric analysis and flow-volume loops in obstructive sleep apneic patients. Sleep. 1983; 6: 303-311 PubMed Google Scholar non-O-SAS patients. Thus, results of earlier studies agree on the existence of a relatively high frequency of abnormal flow-volume curves in O-SAS patients, but there is some disagreement on the specificity of these abnormalities.