STimulation to Activate RespIration

Inclusion Criteria:

1. Male or female, 18 years or older, and

2. Able to provide informed consent or have a legally authorized representative (LAR) /Substitute Decision Maker (SDM) who can provide consent, and

3. Have acute onset of new respiratory symptoms or dysfunction within the 2 weeksbefore onset of need for respiratory support, and

4. Have moderate-to-severe arterial hypoxemia defined by one of:

• PaO2:FiO2 ratio <≤200 mm Hg on PEEP ≥ 5 cm H2O, or

• In the absence of an available arterial blood gas, SpO2 ≤97% on FiO2 ≥0.5 andPEEP ≥5 cm H2O with reliable SpO2 trace for the 2 hours immediately precedingeligibility assessment (this correlates to an upper limit of SpO2:FiO2 ratio of 235%) or

• Are receiving inhaled nitric oxide for acute hypoxemia, or

• Are being ventilated in the prone position for acute hypoxemia, and

5. Have been mechanically ventilated for AHRF in the current ICU for <72 hours at thetime of enrolment, and

6. Are expected to require invasive mechanical ventilation ≥ 48 hours after enrollmentin the opinion of the treating clinician, and

7. Have not spontaneously triggered the ventilator for the previous 2 hours and thereis no immediate plan to transition to assisted ventilation.

Exclusion Criteria:

1. Hypoxemia is primarily attributable to acute exacerbation of chronic obstructivepulmonary disease, status asthmaticus, or pulmonary embolism.

2. Underlying chronic parenchymal lung disease that may make recovery/extubation achallenge (e.g., COPD, pulmonary fibrosis).

3. Broncho-pleural fistula at the time of eligibility assessment.

4. Severe hemodynamic instability (requiring norepinephrine or epinephrine > 0.5mcg/kg/min)

5. Require extracorporeal membrane oxygenation.

6. Pre-existing neurological, neuromuscular or muscular disorder or known phrenic nerveinjury that could affect the respiratory muscles.

7. BMI >70 kg/m2.

8. Contraindications to left internal jugular vein or left subclavian veincatheterization (e.g., infection at the access site, known central venous stenosis,septic thrombophlebitis, left internal jugular ECMO cannula in situ, poor targetvessels).

9. Patient expected to transition to fully palliative care within 72 hours ofenrollment.

10. Severe liver disease (Child-Pugh Score ≥10)

11. Treating clinician deems enrollment not clinically appropriate.

12. Currently enrolled in any other study of an investigational drug or device, whichmay affect the outcomes of the current study.

13. Any electrical device (implanted or external) that may be prone to interaction withor interference from the AeroNova System, including neurological pacing/stimulatordevices and cardiac pacemakers and defibrillators.

14. Known or suspected to be pregnant or lactating.