The purpose of this study is to determine if inspiratory muscle strength training will increase the proportion of ventilator dependent patients weaned versus Sham treated patients.

The inspiratory muscle strength training consists of 4 sets of 6-10 breaths through a threshold inspiratory muscle strength training device, 5 days per week. The inspiratory muscle training is conducted at the highest pressure setting tolerated by the patients. The Sham groups uses an inspiratory muscle trainer that does not increase inspiratory muscle strength. Both the treated and Sham groups participate in progressively lengthening periods of breathing without ventilator as tolerated. Patients are considered weaned when they can breathe for 72 consecutive hours without any ventilator support.

Inclusion Criteria:

• Failure to wean patients in the medial, surgical and intermediate respiratory care units at Shands Hospital
• medically stable
• able to initiate spontaneous breaths
• able to provide informed consent
• able to follow simple instructions

Exclusion Criteria:

• life expectancy < 12 months due to malignancy
• damaged phrenic nerves
• neuromuscular diseases
• heart or lung transplant