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Night Manager
This dedicated module of the controller algorithm is responsible for analysis of the data from each individual
overnight study, calculating and extracting data required for an automatic progression to the next night, and
terminating the overall study when all required overnight studies were successfully completed or the upper limit
of 6 consecutive overnight attempts was reached.
During an OA Study, the MATRx plus system operates in one of two modes, either ACTIVE or PAUSED. The
presence of either mode is displayed to the patient on the Tablet and will be marked on the data displayed in
the data viewer when the HCP is reviewing the data. The active study time starts when the initial sleep waiting
period as described above is completed. The active mode is triggered by the patient when beginning the study
and, while in this condition, the device functions as intended. The pause mode interrupts the active mode owing
to an action by the patient’s action to cease the test temporarily (e.g. the need to go to the bathroom during the
study), an error within the machine (e.g. bluetooth disconnection, software error, actuator pause due to excessive
resistance or positioner error), or an unexpected value for an airflow or oxygen saturation signals. For example,
the loss of a valid O2 saturation signal or deterioration of the airflow signal below acceptable levels will cause the
system to switch from active to passive modes. The system automatically resumes in the active mode when these
deficiencies are corrected, except for either the actuator pause or user-initiated pause, which requires the patient’s
action to reinitiate the study by hitting the button displayed on the Tablet. During the paused mode, the data
is gathered and is available for review by the HCP, however the data is clearly marked and is not included in the
automatic analysis. A successful study night requires a minimum of 4 hours of active study time.
Safety Features
An important safety feature of the control system is that the movement of the mandible is constrained to
small step size movements of up to 0.3mm, and the position of the mandible is constrained to the patient’s
range of motion as measured and entered into the system by the HCP during study set up. These limits place
ultimate strict protrusive and retrusive limits on the mandibular position that cannot be exceeded under any
circumstances. For instance, if a continuous string of very severe respiratory events were to occur, the controller
could protrude the mandible, at maximum, only to the protrusive limit imposed on the system. The mandible
might be held there but would never move beyond this limiting position.
Another safety feature of the control system is its stability. Extreme stability is conveyed on the system by the
unidirectional operation of the controller in the RE elimination condition on the dynamic study night. Specifically,
protrusive movements are executed in response to the occurrence of REs, but retrusive movements are not
allowed in the absence of REs in this condition. Rather, absence of REs causes a shift to the alternate condition,
airway maximization. The earliest possible retrusive movement after entering this condition is a 0.6mm retrusion
occurring after a delay equal to the cumulative period of a series of five breaths. This requirement of a condition
shift and imposed delay effectively eliminates the possibility of a behavior displaying overshoot or negative
feedback oscillation.
