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.