WE CLAIM:
1. A mechanical ventilation system (1), comprising:
a mechanical ventilator (2) configured to deliver ventilation to a patient; and an electronic controller (13) programmed to control the mechanical ventilator to perform a mechanical insufflation-exsufflation (MI-E) therapy method (100) including performing a MI-E cycle including:
(i) during an insufflation cycle, delivering pressure to the patient at a positive insufflation gauge pressure;
(ii) during an exsufflation cycle following step (i), delivering pressure to the patient at a negative exsufflation gauge pressure and detecting whether an upper airway collapse occurs; and
(iii) reducing a magnitude of the negative exsufflation gauge pressure if an upper airway collapse is detected in step (ii).
2. The mechanical ventilation system (1) as claimed in claim 1, wherein the step (iii) reduces the magnitude of the negative exsufflation gauge pressure by a predetermined pressure magnitude decrease increment.
3. The mechanical ventilation system (1) as claimed in claim 2, wherein the predetermined pressure magnitude decrease increment value is 5 cm H2O.
4. The mechanical ventilation system (1) as claimed in any one of claims 1-3, wherein the MI-E therapy method (100) includes repeating the MI-E cycle until no upper airway collapse is detected at step (ii).
5. The mechanical ventilation system (1) as claimed in any one of claims 1-3, wherein the step (iii) reduces the magnitude of the negative exsufflation gauge pressure to zero if an upper airway collapse is detected in step (ii), and the MI-E therapy method further includes, in response

to detecting an upper airway collapse in step (ii):
performing a second MI-E cycle (200) after the step (iii) including:
(iv) during an insufflation cycle, delivering pressure to the patient at the positive insufflation gauge pressure;
(v) during an exsufflation cycle following step (iv), delivering pressure to the patient at the negative exsufflation gauge pressure; and
(vi) increasing the magnitude of the negative exsufflation gauge pressure if an upper airway collapse is not detected in step (v).
6. The mechanical ventilation system (1) as claimed in claim 5, wherein the second MI-E
cycle (200) further includes:
repeating the second MI-E cycle until an upper airway collapse is detected at step (vi).
7. The mechanical ventilation system (1) as claimed in claim 6, wherein upon detection of
and upper airway collapse at step (vi), the step (vi) decreases the magnitude of the negative
exsufflation gauge pressure by a predetermined pressure magnitude decrease increment, and the
MI-E therapy method (100) further includes, in response to detecting an upper airway collapse in
step (vi):
performing a third MI-E cycle (200) after the step (vi) including:
(vii) during an insufflation cycle, delivering pressure to the
patient at the positive insufflation gauge pressure;
(viii) during an exsufflation cycle following step (iv),
delivering pressure to the patient at the negative exsufflation gauge
pressure; and
(ix) maintaining the magnitude of the negative exsufflation
gauge pressure if an upper airway collapse is not detected in step
(viii).

8. The mechanical ventilation system (1) as claimed in claim 7, wherein the third MI-E
cycle (200) further includes:
decreasing the negative exsufflation gauge pressure by the predetermined pressure magnitude decrease increment when an upper airway collapse is detected at step (ix).
9. The mechanical ventilation system (1) as claimed in either one of claims 7 and 8, wherein
the third MI-E cycle (200) further includes:
once the upper airway collapse is detected at step (ix), recording the negative exsufflation gauge pressure as the negative exsufflation gauge pressure for a subsequent MI-E cycle of the MI-E therapy method.
10. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
using a flowmeter (10), measuring an airway flow rate of the patient at a predetermined time or time interval in the exsufflation cycle; and
comparing the measured airway flow rate with a predetermined threshold to detect whether an upper airway collapse occurs.
11. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
using a flowmeter (10), measuring a volume of air exhaled by the patient at a predetermined time in the exsufflation cycle; and
comparing the measured volume of air with a predetermined threshold to detect whether an upper airway collapse occurs.
12. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
using a flowmeter (10), measuring a rate of change of airway flow at a predetermined time or time interval in the exsufflation cycle; and
comparing the measured rate of change of airway flow with a predetermined threshold to detect whether an upper airway collapse occurs.

13. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
measuring a rotation rate of a blower (12) of the mechanical ventilator (2) at a predetermined time or time interval in the exsufflation cycle; and
comparing the measured rotation rate of the blower with a predetermined threshold to detect whether an upper airway collapse occurs.
14. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
measuring a pressure produced by a blower (12) of the mechanical ventilator (2) at a predetermined time or time interval in the exsufflation cycle; and
comparing the measured pressure produced by the blower with a predetermined threshold to detect whether an upper airway collapse occurs.
15. The mechanical ventilation system (1) as claimed in any one of claims 1-9, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
measuring an airway flow rate of the patient using a flowmeter (10) and an airway pressure of the patient using a pressure meter (11);
determining an airway reactance from the measured airway flow rate and the measured airway pressure; and
detecting whether an upper airway collapse occurs based on the determined airway reactance.
16. The mechanical ventilation system (1) as claimed in any one of claims 1-15, wherein
the detecting of whether an upper airway collapse occurs in the operation (iii) includes:
superimposing an ac oscillation on the pressure delivered to the patient at the negative exsufflation gauge pressure;
while superimposing the ac oscillation, measuring a respiratory metric comprising an airway flow rate of the patient using a flowmeter (10) or an airway pressure of the patient using a pressure meter (11); and

detecting whether an upper airway collapse occurs based in part on an ac component of the measured respiratory metric.
17. A mechanical ventilation system (1), comprising:
a mechanical ventilator (2) configured to deliver ventilation to a patient; and an electronic controller (13) programmed to control the mechanical ventilator to perform a mechanical insufflation-exsufflation (MI-E) therapy method (300) including performing a MI-E cycle including:
(i) during an insufflation cycle, delivering pressure to the patient at a positive insufflation gauge pressure; and
(ii) during an exsufflation cycle following step (i), delivering pressure to the patient at a negative exsufflation gauge pressure; and
(iii) analyzing one or more respiratory metrics of the patient during the delivery of the pressure to the patient at the negative exsufflation gauge pressure.
18. The mechanical ventilation system (1) of claim 17, wherein the one or more respiratory
metrics includes at least a cough metric indicating whether the patient is coughing; and wherein
the MI-E cycle includes:
(iv) reducing a magnitude of the negative exsufflation gauge pressure during the delivering if the analyzing exhale flow determines that upper airway collapse is predicted to occur.
19. The mechanical ventilation system (1) as claimed in claim 18, wherein if the cough metric indicates that the patient is coughing, the MI-E cycle includes performing another iteration of the MI-E cycle.
20. The mechanical ventilation system (1) as claimed in claim 18, wherein if the cough metric indicates that the patient is not coughing, the MI-E cycle includes:
reducing a magnitude of the negative exsufflation gauge pressure multiplying the negative exsufflation gauge pressure by a constant, the constant having a value of less than 1.

21. A non-transitory computer readable medium (15) storing instructions by an electronic
controller (13) of a mechanical ventilator (2) to control the mechanical ventilator to perform a
mechanical insufflation-exsufflation (MI-E) therapy method (400) including performing a MI-E
cycle including:
(i) during an insufflation cycle, delivering pressure to the patient at a positive insufflation gauge pressure;
(ii) during an exsufflation cycle following step (i), delivering pressure to the patient at a negative exsufflation gauge pressure;
(iii) reducing a magnitude of the negative exsufflation gauge pressure to zero during step (ii); and
(iv) increasing a magnitude of the negative exsufflation gauge pressure during the delivery if an analysis predicts an upper airway collapse will not occur during the exsufflation cycle.
22. The non-transitory computer readable medium (15) as claimed in claim 21, wherein if
the analyzing predicts an upper airway collapse will not occur during the exsufflation cycle at step
(iv), the increasing includes:
increasing a magnitude of the negative exsufflation gauge pressure by adding a constant value to the negative exsufflation gauge pressure by a constant.
23. The non-transitory computer readable medium (15) as claimed in claim 22, wherein if
the analyzing predicts an upper airway collapse will not occur during the exsufflation cycle at step
(iv), the MI-E cycle includes:
recording the negative exsufflation gauge pressure as the negative exsufflation gauge pressure for a subsequent MI-E cycle of the MI-E therapy method (400).
24. The non-transitory computer readable medium (15) as claimed in claim 23, wherein
the MI-E therapy method (400) further includes, in response to detecting an upper airway collapse
in step (iv):
performing a second MI-E cycle after the step (iv) including:
(iv) during an insufflation cycle, delivering pressure to the

patient at the positive insufflation gauge pressure;
(v) during an exsufflation cycle following step (iv), delivering pressure to the patient at the recorded negative exsufflation gauge pressure.