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 hav e been shown to decrease tracheal injury, However, injury still occurs in p atients requiring prolonged mechanical ventilation and prevents weaving, de lays decannulation, prolongs hospitalization, and may totally obstruct the airway. We describe 37 patients, including the first reported case of failu re to wean due to tracheal obstruction, Methods: Over a 3-year period, from September 1994 to August 1997, the hosp ital records of 37 patients requiring prolonged mechanical ventilation (> 4 weeks) and found to have tracheal obstruction were reviewed retrospectivel y, They were a subgroup of 756 patients admitted to hospitals during the sa me period. The average endotracheal/tracheostomy cannulation time was 3 wee ks/12 weeks (range 2 to 4 weeks/8 to 14 weeks). Average age was 76 years (r ange, 34 to 81), Underlying diseases included COPD, postcoronary artery byp ass graft surgery, postpneumonectomy, severe pneumonia, acute lung injury, and ischemic heart disease. Results: AII 37 patients who initially faded to wean had difficulty in brea thing 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, d ecreased peak airway pressures, and allowed the patient to breathe more eas ily. 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 we aned within a week. The two patients who still failed to be weaned were sub sequently 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.