Pivotal Evaluation of Abdominal Neuromuscular Electrical Stimulation (VentFree) for Weaning From Mechanical Ventilation

The objective of this study is to evaluate the efficacy of the VentFree Respiratory Muscle Stimulator (VentFree) in critically ill adult patients who require invasive mechanical ventilation, when compared to sham.

Approximately 40% of patients who receive invasive ventilation require more than four days of ventilator support. Every additional day of mechanical ventilation results in increased patient morbidity and mortality and increased economic cost. Mechanically ventilated patients often develop expiratory muscle weakness, which has been linked to failed extubation and weaning. Neuromuscular electrical stimulation (NMES) uses electrical pulses to induce a muscle contraction and has been shown to reduce or retard muscle atrophy. NMES applied to the abdominal wall muscles has been shown to improve respiratory function and assist ventilator weaning in spinal cord injury. Liberate Medical has previously shown that NMES applied to the abdominal wall muscles in synchrony with exhalation is feasible in patients receiving invasive mechanical ventilation. This study is a pivotal evaluation of the efficacy of exhalation synchronized abdominal NMES to assist ventilator weaning in critically ill patients.

Inclusion Criteria: 1. Participant is ≥ 22 years of age. 2. Participant has been receiving invasive mechanical ventilation for ≥ 24 hours. Exclusion Criteria: 1. Participant has been receiving invasive mechanical ventilation for \> 96 hours. 2. Participant is scheduled or expected to be disconnected from mechanical ventilation ≤ 24 hours after enrollment. 3. Participant was intubated for ≥ 24 hours during a prior episode of invasive mechanical ventilation during current hospitalization. 4. Participant has a BMI ≥ 40 Kg/m2. 5. Participant has no contraction of the abdominal wall muscles in response to abdominal FES as determined by ultrasound. 6. Participant has a pre-existing neuromuscular or muscular disorder that could affect the respiratory muscles (e.g., spinal cord injury or Guillain-Barré syndrome). 7. Participant has had open abdominal surgery ≤ 4 weeks prior to enrollment. 8. Participant has open or damaged skin at area of electrode placements. 9. Participant has a pacemaker and/or implanted electronic device. 10. Participant is known or expected to be pregnant. NOTE: A negative urine or blood pregnancy test will be documented during screening for women of child-bearing potential. 11. Participant is actively pharmacologically paralyzed at the time of enrollment. NOTE: Participants receiving neuromuscular blockers may be enrolled after a ≥ 12-hour washout period. 12. Participant is tracheostomized at the time of enrollment. 13. Participant is on home non-invasive ventilation (except for CPAP or BiPAP for obstructive sleep apnea). 14. Participant is receiving or expected to receive comfort measures (palliative, hospice, comfort care, etc.) at the time of screening or enrollment. 15. Participant is participating in any of the following: * A study with the same or similar primary endpoint * A study investigating electrical stimulation or respiratory muscle therapy * Any study in which the investigator determines may interfere with the results of this study 16. Participant is unable or unwilling to comply with protocol requirements, including assessments, tests, and follow-up visits. 17. Participant has any other medical condition which in the opinion of the Investigator will make participation medically unsafe or interfere with the study results. 18. Participant or legally authorized representative is unwilling to provide written informed consent. 19. Participant or legally authorized representative is unable to provide written informed consent.