Table 1.

Criteria used for identifying patients receiving tracheostomies or initiated on chronic ventilation

Group	Criteria
Tracheostomy alone	Patient admitted postoperatively after tracheotomy or had a tracheostomy intervention that was not present on admission Tracheostomy that was present on discharge
Chronic respiratory failure	Repeated attempts to wean from assisted ventilation have failed for at least 1 month No superimposed acute respiratory disease or Patient has a diagnosis that confers no prospect of being weaned from the ventilator: spinal muscular atrophy type 1a hereditary myopathies/muscular dystrophiesa Arnold-Chiari malformation with hydrocephalusa vertebral fracture with spinal cord injury and paralysisa diaphragm paralysisb spina bifidab cystic fibrosisb
Invasive ventilation	Above criteria for tracheostomy or admitted with a tracheostomy but not on mechanical ventilatory support Met criteria for chronic respiratory failure Discharged using mechanical ventilation or invasive continuous positive airway pressure
Noninvasive ventilation	Not admitted using noninvasive ventilation Met criteria for chronic respiratory failure Discharged using bilevel positive airway pressure or noninvasive continuous positive airway pressure

^aConsidered as implying “no prospect of being weaned” for patients using invasive and noninvasive ventilation

^bConsidered as implying “no prospect of being weaned” for patients using invasive ventilation only