The role of tracheostomy in weaning from mechanical ventilation.

A common clinical observation is that patients wean more rapidly from mechanical ventilation following tracheotomy. Expected changes in tube resistance and dead space are not adequate to explain this observation in adult patients. Theoretical considerations are too complicated to allow evaluation of expected changes in work of breathing following tracheotomy. The resistance of the upper airway is about the same as breathing quietly through an 8.0 mm endotracheal tube; however, many patients experience a higher work of breathing following extubation. This is not true in infants, in whom the reduction in airway diameter is profound and a marked reduction in resistance is seen following extubation. The other benefits of tracheostomy include better secretion removal, improved oral hygiene, less laryngeal damage, and ability to eat and speak. These should be considered when proposing this procedure. There may be less late ventilator-associated pneumonia following early tracheotomy. The assumed better safety of tracheostomy has been questioned. That patients appear to wean more rapidly is probably accounted for by the variety of factors mentioned above.