Introduction
Following tracheostomy placement, infants and children with bronchopulmonary dysplasia (BPD) and tracheostomies are a vulnerable population. This group has twice the risk of rehospitalization as infants without BPD, predominantly for respiratory infections,1,2 and a mortality rate of 11-20% by 2 years of age.1,3,4 Among young children with BPD, the expected respiratory course is one of improvement in lung function with time and alveolar growth.5 For those who require tracheostomy placement for chronic respiratory support, the weaning of support is widely viewed as a sign of improving pulmonary function, with liberation from ventilation generally expected by 24-30 months.6-9 Subsequent decannulation is also anticipated, and is viewed as a sign of airway growth and patency and respiratory stability. However, only one-third to half of children with BPD and tracheostomies follow this trajectory of lung health improvement.1,3,6-8,10-12 The reasons why other children are unable to achieve improved lung health are unclear.
Identification of pathogenic bacteria during respiratory culture testing is common among children with tracheostomies. We hypothesize that respiratory bacteria, whether acute infectious or chronically colonizing bacteria, may influence prolonged tracheostomy dependence and mortality. Identification of Pseudomonas aeruginosa in the respiratory tract of children with tracheostomies has been associated with increased risk of re-hospitalization for respiratory infection.13Respiratory tract colonization with P. aeruginosa and other bacteria are well-defined entities and well-documented causes of lung function decline in children and adults with cystic fibrosis.14-18 Although long-term colonization has not been defined in children with tracheostomies, recurrent P. aeruginosa isolation on tracheostomy aspirate cultures has been associated with poor short-term outcomes, including longer hospitalizations and higher readmission rates.13,19However, long term outcomes of acute and recurrent bacterial isolation have not been assessed among children with tracheostomies or those with BPD.
In this study of children with BPD and tracheostomies, we sought to assess the association of respiratory culture organism isolation, particularly P. aeruginosa , and lung health outcomes at 3 years post-tracheostomy placement, including ongoing need for respiratory support, delayed decannulation, and death. We hypothesized that children with P. aeruginosa bacterial identification would have higher likelihood of each poor outcome compared with children who did not have such bacterial isolation.