Automated Ventilator Controlled Weaning vs Daily Spontaneous Breathing Trial in Difficult to Wean ICU Patients

Inclusion Criteria: * Age ≥ 18 years * Intubated with endotracheal tube * Requiring mechanical ventilation for \> 72 hours * Meets weaning criteria: Improvement or resolution of the underlying process that precipitated need for mechanical ventilation, PaO2 ≥ 60 mm Hg on PEEP and FiO2 Requirements of ≤ 8 cm H2O and FiO2 ≤ 0.50, Stable oxygenation: PEEP and FiO2 requirements not increased in the past 24 hrs, Ability to initiate an inspiratory effort and trigger the ventilator, Subject enrollment approved by the primary service attending physician Exclusion Criteria: * Pregnancy * Patients with tracheostomy or planned tracheostomy prior to attempt to extubate * Patients with known airway patency issues that are anticipated to delay extubation. * Patients with neurological injury in whom care is likely to be withdrawn * Patients with cervical spinal cord injury. * Prospective subject or surrogate consenter does not fully understand the implications of the study because of a language barrier.