Mild to moderate sleep respiratory events: one negative night may not be enough.
OBJECTIVE
Reports on the reproducibility of apnea-hypopnea indexes (AHIs) across sequential polysomnography (PSG) sessions are conflicting, leading to a lack of clear recommendations on the optimal use of this technique: is one night of monitoring sufficient or is a second night required in order to safely reject the diagnosis?


METHODS
Retrospective comparison of two consecutive nights.


METHODS
Sleep unit of a tertiary-care facility.


METHODS
Two hundred forty-three subjects with suspected sleep apneas.


METHODS
Two sequential PSG sessions in a sleep unit.


RESULTS
Using analysis of covariance for repeated measures, with age and body mass index as covariates and gender as a cofactor, a classic first-night effect was found for sleep variables. In addition, a night effect was demonstrated for sleep respiratory variables. Moreover, the high variability of AHIs showed that many patients had their condition diagnosed on only one of the two nights, and more often on the second night than on the first. The gain in detection by adding a second night when the results of testing on the first were negative was between 15% and 25%, according to the AHI obtained on night 1.


CONCLUSIONS
Considering the disability associated with sleep apnea/hypopnea syndrome, as well as its global cost for society, the present study shows that it is worth performing two consecutive PSG sessions or at least a second one when the result of the first one is negative in all patients admitted for apnea detection.
Centre Hospitalier Universitaire Brugmann, Université Libre de Bruxelles, Brussels, Belgium. lebono@ulb.ac.be
O
O
Le Bon
G
G
Hoffmann
J
J
Tecco
L
L
Staner
A
A
Noseda
I
I
Pelc
P
P
Linkowski
D015992:Body Mass Index; D001944:Breath Tests; D002940:Circadian Rhythm; D003937:Diagnosis, Differential; D004185:Disability Evaluation; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000032:analysis; D017286:Polysomnography / Q000379:methods*; D015203:Reproducibility of Results; D012119:Respiration; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation
D010100:Oxygen