Upper-Airway-Stimulation (UAS) is regarded as a well-established therapy option for
obstructive sleep apnea (OSA) in PAP failure. Previous studies showed that treatment
is affected by electrode configuration and tongue motion patterns. Up to now, there
is no data regarding the influence of respiratory sensing and whether respiratory
sensing contributes to successful UAS.
Patients implanted for at least 6 months, beeing therapy responders and showing good
respiratory sensing were recruited for the study. To reduce interrater and night-to-night
variability, doubled home sleep tests were conducted (Watch-PAT®, Itamar, Israel).
After initial measurements (M1), the sensing signal was inverted (Inverse OFF to ON;
M2) without changing other parameters. Two weeks later, the signal was converted back
again and the sensitiveness of the breathing cycle detection was turned to a very
low state (M3). Another two weeks later, all parameters were changed back to initial
values for 2 weeks (M4).
At M2 and M3, there the apnoea hypopnoea index and oxygen desaturation index doubled
for the entire night and for the time in supine position. Daytime sleepiness values
were stable during the whole study at normal values. Due to strict ethic obligations,
the study was stopped after 3 patients worsening under study conditions.
Correct respiratory sensing and signalling is needed for controlling OSA using UAS.
Therefore implanting centres should continue to achieve perfect respiratory sensing
during implantation and therapy adjustment with the utmost diligence.
