The Role of Pulmonary Function Testing in Pediatrics

The stereotype of school-aged children is that of runny noses and annual cold symptoms. Upper respiratory infections tend to spread like wildfires under the ideal conditions of close quarters in school, suboptimal hand hygiene, and maturing immune systems. It’s not uncommon for kids to get sick even multiple times per year, bouncing back quickly with the resiliency of youth.

But for many kids, regular cold and flu symptoms may be a sign of something more serious. According to the American Lung Association (ALA), asthma is the most common chronic condition in children, affecting over six million kids in the United States alone.¹ Over half of those kids can be expected to have an asthma flare-up in any given year, leading to absenteeism, loss of social contact, and even long-term effects from the remodelling of their airways. Globally, the picture is not much better, with approximately 14% of the world’s children affected by the condition, and with asthma being one of the leading causes of hospitalization of children under five years of age.²

Apart from asthma, kids are also impacted by a variety of other respiratory conditions. Cystic fibrosis is perhaps one of the most well-known, affecting not only the lungs but organs like the liver and pancreas. Bronchopulmonary dysplasia, most often seen in premature newborns who need mechanical ventilation or oxygen support in their first weeks of life, affects between 10,000 and 15,000 babies every year.³ Less common conditions, like primary ciliary dyskinesia (PCD), congenital abnormalities, and even interstitial lung diseases affect thousands more. In total, respiratory issues account for nearly 1 in 4 of all pediatrician visits.

Moreover, diagnosis and monitoring can be tricky with many of these conditions. Asthma in particular can be difficult to diagnose, with a wide range of symptoms from chronic cough to atopic reactions to various allergens to bronchospasm that’s only brought on by exercise. As with adults, chronic respiratory symptoms can be vague, nonspecific, and difficult to isolate. That leads to delayed diagnosis and increased risk of lifelong respiratory impairment.

In order to make the right diagnosis, you need the right tests. Along with a detailed history and physical examination, pulmonary function testing plays an important role in identifying lung issues, categorizing pathologies, and developing a personalized therapy plan tailored to the unique needs of every patient. These tests usually start with pre- and post-bronchodilator spirometry, which provides essential information about airway reactivity and responsiveness in conditions like asthma. Analyzing lung volumes with measurements like multiple breath washout (MBW) and the lung clearance index (LCI) are invaluable for monitoring lung function in cystic fibrosis. Monitoring diffusion capacity in the lung of carbon monoxide (DLCO) can also help detect rare diagnoses like interstitial lung disease, giving clinicians every possible tool to enhance clinical decision making.