[Utility of nocturnal oximetry for case finding in patients with suspected sleep apnea syndrome].
OBJECTIVE
Pulse oximeter is a useful screening device for SAS. We studied whether measurement of SaO2 could identify patients with SAS and evaluate the severity of SAS.


METHODS
174 snorers were assessed clinically and then underwent formal PSG and oximetry test at the same time. From the oximetry data, the percentage of time spent at SaO2 below 90% (SIT90%), waking SaO2(H SaO2%), the lowest SaO2(L SaO2%) during sleep, the mean SaO2(M SaO2%) and the number of oxygen desaturation > or = 4% per hour (DI4) were calculated. We also divided 100 cases among them into four groups by AHI, which were G0(AHI < 5), G1(AHI 5-19), G2(AHI 20-39), G3(AHI > or = 40), and evaluated whether the SIT90, ISaO2, MSaO2 and DI4 are different among the four groups.


RESULTS
There was an statistically significant correlation (r = 0.91 P < 0.001) between DI4 and AHI. DI4 > or = 5 per hour identified patients with AHI > 5 with a sensitivity of 94%; DI4 > or = 15 per hour identified patients with AHI > 5 with a specificity of 98%, and for patients with AHI > or = 20, the sensitivity was 100%. The SIT90 and DI4 were significantly different among the four groups (P < 0.01).


CONCLUSIONS
Oximetry with DI4 < 5 practically excludes clinically significant SAS, and DI4 > or = 15 identified almost all of them. SIT90 and DI4 could be used as parameters in evaluating the severity of SAS.
Han
F
F
Department of Respirology, People's Hospital, Beijing Medical University, Beijing 100044.
Chen
E
E
Wei
H
H
D002940:Circadian Rhythm; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D012680:Sensitivity and Specificity; D012891:Sleep Apnea Syndromes / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D012913:Snoring / Q000097:blood / Q000503:physiopathology
D010100:Oxygen