title: Night-to-night variation of the oxygen desaturation index in sleep apnoea syndrome.
abstract: The current study investigated the night-to-night variability and diagnostic accuracy of the oxygen desaturation index (ODI), as measured by ambulatory monitoring, in the diagnosis of mild and moderate obstructive sleep apnoea-hypopnoea syndrome. To assess the variability of the ODI, 35 patients were monitored at home during 7 consecutive nights by means of a portable recording device, the MESAM-IV. The ODI variability factor and the influence of age, body mass index (BMI), alcohol, and body position were assessed. Furthermore, the diagnostic accuracy of the MESAM-IV was measured by comparison with polysomnographical outcomes in 18 patients. During home recording, the median ODI was 10.9 (interquartile range: 5.8-16.1) across the patients. Although the reliability of the ODI was adequate, the probability of placing the patient in the wrong severity category (ODI < or =15 or ODI >15) when only one single recording was taken is 14.4%. ODI variability was not significantly influenced by age, BMI, time spent in a supine position, or mild dosages of alcohol. A good correlation was found between the apnoea-hypopnoea index and the ODI. In conclusion, the findings suggest that the diagnostic accuracy of the MESAM-IV is strong, since the oxygen desaturation index is correlated with the apnoea-hypopnoea index. In most obstructive sleep apnoea-hypopnoea syndrome patients, oxygen desaturation index variability is rather small, and screening could be reliably based on single 1-night recordings.
authors.affiliation: Centre of Sleep Medicine, Dept of Cardiology and Pulmonology, Charité--Universitätsmedizin Berlin, Campus Mitte, Humboldt University, Luisenstr. 13a, D-10117 Berlin, Germany. ingo.fietze@charite.de
authors.forename: I
authors.initials: I
authors.lastname: Fietze
authors.forename: K
authors.initials: K
authors.lastname: Dingli
authors.forename: K
authors.initials: K
authors.lastname: Diefenbach
authors.forename: N J
authors.initials: NJ
authors.lastname: Douglas
authors.forename: M
authors.initials: M
authors.lastname: Glos
authors.forename: M
authors.initials: M
authors.lastname: Tallafuss
authors.forename: W
authors.initials: W
authors.lastname: Terhalle
authors.forename: C
authors.initials: C
authors.lastname: Witt
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D017286:Polysomnography; D011187:Posture; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000503:physiopathology; D018709:Statistics, Nonparametric
chemical_list: D010100:Oxygen