Minimal recruitment. very few patients available with eligibility criteria

This is a study to evaluate whether PEEP adjusted by use of an esophageal balloon to overcome negative transpulmonary pressure; or adjusted by use of "CStat" to achieve the best effective static compliance will have any effect on outcomes with respect to ventilator weaning in tracheotomized morbidly obese patients (BMI >=40) with at least one failed prior weaning attempt.

Tracheotomized morbidly obese patients (BMI >= 40) who had failed an initial attempt at ventilator weaning (defined in the investigators study as ventilator dependent) were randomly assigned to one of two methods for setting Positive End Expiratory Pressure (PEEP).

Patients randomized to the esophageal balloon arm (ESO group) had their PEEP adjusted to overcome negative transpulmonary pressure and maintain a positive transpulmonary pressure (Ptp) of 0 to 10 cm H20 - targeting as close to zero as possible.

Patients randomized to the static effective compliance arm (CStat group) had their PEEP adjusted to achieve the best static effective compliance as automatically calculated and displayed on the graphic interphase of the hamilton G5 or Galileo ventilator. For this group, the PEEP was adjusted in increments of 3 cm H20 until there was a less than 5% observed improvement in the static effective compliance. the PEEP with the best Cstat was chosen.

At the end of the intervention period, this intervention cohort (termed "PEEP intervention cohort") will be compared to a group of historical controls to compare the efficiency of a PEEP-based weaning protocol to traditional weaning methods.

The investigators hypothesized that PEEP levels titrated by use of an esophageal balloon to maintain a positive transpulmonary pressure between 0 to 10 cm H20, would lead to improved outcomes with respect to ventilator weaning in this subset of patients.

Inclusion Criteria:

• Morbidly obese patients with BMI of 40 or greater
• Ventilator dependent patients (defined as at least one prior failure at weaning)
• Tracheotomized
• No active underlying lung disease that would preclude ventilator weaning
• Stable hemodynamics
• Patient/ family able to give consent
• No naso-facial abnormalities that would interfere with placement of an esophageal balloon
• Fio2 <= 60%
• Patient able to tolerate Pressure Support ventilation

Exclusion Criteria:

• Lack of consent
• Patient deemed not weanable from mechanical ventilation as per the clinical judgement of the pulmonary physician
• Significant lung, heart or neuromuscular disease that would interfere with or preclude ventilator weaning, including an active ongoing lung infection.
• Contraindications to placement of an esophageal pressure monitoring device - such as ulcerations, tumors, diverticulitis, uncontrolled bleeding varices, sinusitis, epistaxis or recent nasopharyngeal surgery