Auto-CPAP therapy for obstructive sleep apnea: induction of microarousals by automatic variations of CPAP pressure?
OBJECTIVE
To investigate the frequency of microarousals (MA) associated with pressure changes during auto-CPAP therapy (APAP) for obstructive sleep apnea (OSA).


METHODS
Patients with OSA were studied by polysomnography during APAP therapy (Somnosmart). The MA were classified on the basis of concomitant changes in APAP pressure.


METHODS
Sleep laboratory of a university hospital


METHODS
30 patients with moderate to severe OSA.


RESULTS
The mean AHI during APAP was 4.7+/-4.7, the mean arousal index was 14.5+/-6.6 per hour. During epochs with a pressure variation greater than 0.5 mbar, significantly more MA occurred (0.30+/-0.17 MA per epoch) than in epochs with constant treatment pressure (0.10+/-0.054 MA per epoch; p<0.001). There were more MA during pressure-increase epochs than during pressure-decrease epochs (0.42+/-0.24 vs. 0.16+/-0.12 MA per epoch; p<0.001). 82.5 percent of the MA were not preceded by a significant change in pressure (at least 0.5 mbar within 30 sec.), 10.6% were associated with a significant prior increase and 6.9% with a significant prior decrease in pressure. The percentage of MA preceded by a significant pressure variation varied between 2.3% and 61%, with a mean of 18.9%.


CONCLUSIONS
The overall frequency of MA was low, and in most individuals the relative amount of "pressure-associated MA" was not significant. However in some individuals it cannot be excluded that some additional MA may have been induced by pressure variations. Should it prove possible to prevent such "pressure-associated MA" by optimizing the regulation of APAP pressure, the overall clinical effect of APAP treatment may be improved.
Fuchs
Florian S
FS
Department of Medicine I, University of Erlangen-Nuremberg, Erlangen, Germany.
Wiest
Gunther H
GH
Frank
Michael
M
Harsch
Igor A
IA
Schahin
S Pour
SP
Hahn
Eckhart G
EG
Ficker
Joachim H
JH
D000328:Adult; D000368:Aged; D001143:Arousal / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods*; D012646:Self Administration; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000628:therapy*