Significant tracheal obstruction causing failure to wean in patients requiring prolonged mechanical ventilation: a forgotten complication of long-term mechanical ventilation.

INTRODUCTION Modern low-pressure, high-volume cuffed tracheotomy tubes have been shown to decrease tracheal injury. However, injury still occurs in patients requiring prolonged mechanical ventilation and prevents weaning, delays decannulation, prolongs hospitalization, and may totally obstruct the airway. We describe 37 patients, including the first reported case of failure to wean due to tracheal obstruction. METHODS Over a 3-year period, from September 1994 to August 1997, the hospital records of 37 patients requiring prolonged mechanical ventilation (> 4 weeks) and found to have tracheal obstruction were reviewed retrospectively. They were a subgroup of 756 patients admitted to hospitals during the same period. The average endotracheal/tracheostomy cannulation time was 3 weeks/12 weeks (range 2 to 4 weeks/8 to 14 weeks). Average age was 76 years (range, 34 to 81). Underlying diseases included COPD, postcoronary artery bypass graft surgery, postpneumonectomy, severe pneumonia, acute lung injury, and ischemic heart disease. RESULTS All 37 patients who initially failed to wean had difficulty in breathing and developed intermittent high peak airway pressures either early or during the weaning process or just on being ventilated. The insertion of a longer tracheal tube bypassed the obstruction, reestablished the airway, decreased peak airway pressures, and allowed the patient to breathe more easily. The obstruction was confirmed on bronchoscopy. Treatment consisted of either placement of a longer tracheal tube (34 of 37 patients) or placement of a tracheal stent. All but two of the patients (5.4%) were able to be weaned within a week. The two patients who still failed to be weaned were subsequently diagnosed as having amyotrophic lateral sclerosis. CONCLUSION Tracheal obstruction in patients requiring prolonged mechanical ventilation prevented weaning. Reestablishment of the airway with a longer tracheal tube or tracheal stent allowed most of the patients to be weaned.