Risk factors for lung dysfunction
A variety of
risk
factors are related to impaired lung function in children with
OSA.[24,25] However, the
independent risk factors
for lung function decline in pediatric OSA patients are unknown. We used
12 clinical indicators, including a patient history and lab test results
in our risk factor analysis, and found that histories of chronic cough
and concomitant asthma were the independent risk factors for lung
dysfunction in children with OSA. Asthma and asthma-like symptoms,
protracted bronchitis, and upper airway cough syndrome were detected in
order of frequency as the reason for chronic cough in
children.[26]However, the evidence for pediatric OSA as a cause of chronic cough is
still ambiguous. An evaluation of children with chronic cough and
obstructive sleep apnea at a single medical center showed that the
superposition of both those factors on top of lower airway mucosal
inflammation further damages lung function and aggravates the
pre-existing airway
hyper-responsiveness.[27]Similarly, 31 of the 45 OSA patients with abnormal lung function in our
study also had asthma. Although none of those patients had recently had
an acute asthma attack, their poor lung function coupled with factors
related to surgical stress caused us to believe that sedatives would
greatly increase the risk for an acute attack of asthma during the
perioperative period.[28,29] Von Ungern-Sternberg
et al[30]demonstrated that an increased pediatric anesthetic risk for
bronchospasm was closely associated with a positive respiratory history
of nocturnal dry cough and wheezing, or a family history of asthma and
atopy. In our study, wheezing and a family history of allergic diseases
were associated with decreased lung function in the univariate analysis,
but were meaningless in the multivariate logistic regression analysis.
Wheezing is a common symptom of asthma, and asthma patients often have a
family history of allergic
diseases.[31] We
speculated that the collinearity between wheezing and a family history
of allergic diseases or asthma led to that result. Therefore, when
children with OSA have these risk factors for lung function decline
(e.g., a history of chronic cough or concomitant asthma), special
attention should be given to providing them with the follow-up airway
intervention to help ensure the safety of surgery.