Randomized Study of the pdSTIM™ System in Failure to Wean Mechanically Ventilated Patients

Inclusion Criteria:

1. Subject is 18 years or older.

2. Subject, or subject's Legally Authorized Representative, understands studyrequirements, study visits, and is willing and able to provide written informedconsent prior to study specific procedures or testing.

3. Subject has been on mechanical ventilation for ≥ 96 hours prior to randomization (intubation or tracheostomy).

4. Subject has failed at least 1 weaning attempt (e.g., site directed spontaneousbreathing trial(s) did not result in liberation).

5. At the time of enrollment, the subject is likely to be ventilated for an additional 48 hours, at minimum, in the opinion of the investigator.

Exclusion Criteria:

1. Subject has been on invasive mechanical ventilation for > 45 days.

2. Subject failed to wean due to pre-existing neurological or neuromuscular issuesaffecting the respiratory muscles (e.g., ALS, phrenic nerve paralysis, inflammatorymuscle disease, underlying myopathy, myasthenia gravis, cervical spinal injury).

3. Subject's medical history, known anatomy or investigator's inability to visualizenecessary anatomical landmarks that could prevent the safe placement of the pdSTIMleads.

4. Subject is at risk of significant hemorrhage or is currently receiving a full doseof systemic anticoagulation (e.g., IV heparin, high dose of subcutaneous heparin.Subjects on prophylactic anticoagulation or daily aspirin regimen on their own arenot excluded unless other exclusion criteria apply).

5. Subject has an implant or external electrical device that may interact or interferewith the pdSTIM System (examples may include cardiac pacemaker, implantabledefibrillator, vagal nerve stimulator, spinal cord stimulator, gastric stimulator,diaphragmatic stimulator).

6. Subject has been diagnosed and has been treated for neck cancer within the past 5years or subject had any prior radiation treatment to the neck.

7. Subject currently has hemodynamic instability due to any cause (e.g., severe sepsis,hemorrhagic shock, or septic shock) with vasopressor support > 0.1 mg/kg/min ofnorepinephrine or epinephrine, or equivalent, or is actively being titrated.

8. Subject has a local infection at or around the proposed pdSTIM Lead insertion site.

9. Subject is neutropenic or has signs of significant immunocompromise. (Subjectsintubated for respiratory failure due to COVID-19 are not excluded unless otherexclusion criteria apply).

10. Subject has severe COPD as indicated by evidence of significant expiratoryobstruction on the ventilator flow waveform or, where ventilator flow waveforms arenot utilized, has a FEV1 ≤ 30%.

11. Subject has pre-existing severe chronic pulmonary fibrosis.

12. Subject has pleural effusion occupying greater than 1/3 of the pleural space oneither side.

13. Subject is currently on or expected to begin neuromuscular blockades.

14. Subject is anticipating withdrawal of life support and/or shift to palliation as thegoal of care with less than 6-months life expectancy.

15. Subject is known or suspected to be pregnant or lactating.

16. Subject is currently enrolled in or exited early from a) any investigational drugstudy or b) an investigational device study that may impact the ability to wean oris directly related to the lungs or diaphragm.