Demystifying Pulmonary Function Tests in Children: Why and How to Do It?

Author: Liu Chuanhe, Chief Physician, Children's Hospital Affiliated to Capital Institute of Pediatrics

Reviewer: Wang Lixiang, Chief Physician, Third Medical Center, PLA General Hospital

The 10th Chairman of the Science Popularization Branch of the Chinese Medical Association

As the name implies, pulmonary function testing is an objective assessment of lung function. As an important organ for gas exchange, the lungs are not only responsible for inhaling oxygen and exhaling carbon dioxide, but also for the important task of oxygen entering the blood from the alveoli and carbon dioxide entering the alveoli from the blood. This process is complex and delicate, and any abnormality in any link may affect the normal function of the respiratory system. Therefore, through pulmonary function tests, we can promptly detect and intervene in respiratory system problems as early as possible to ensure the healthy growth of children.

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1. Methods and selection of pulmonary function tests for children

There are many ways to test children's lung function. Doctors will use different methods for children of different ages and conditions. For school-age children over five or six years old, the commonly used method is the traditional forced expiratory lung function test. This test requires the child to hold the mouthpiece and inhale and exhale according to standard movements, thereby drawing a forced expiratory flow-volume curve (FV curve) including vital capacity. This method is relatively simple to operate, but it requires a high degree of cooperation from the child and can more accurately assess the child's lung function status.

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For preschool children and infants, pulse oscillation pulmonary function tests and tidal breathing pulmonary function tests are often used due to their limited understanding and operational abilities. The pulse oscillation test requires the child to hold a mouthpiece connected to the spirometer and breathe calmly for one minute without leaking air. This method is simple to operate and requires less cooperation from the child. The tidal breathing pulmonary function test needs to be performed while the infant is sleeping. The mask is connected to the pulmonary function testing system to assess their lung function in a calm breathing state. Although the sensitivity and specificity of these methods may be slightly inferior to the traditional forced expiratory flow-volume curve test, they can still provide valuable reference information for doctors in certain circumstances.

2. Indications and significance of pulmonary function tests in children

Children's lung function tests are non-invasive technologies, but they are not performed randomly, but are determined by doctors based on the child's condition. Generally speaking, when a child has obvious symptoms such as wheezing and difficulty breathing, the doctor may recommend a lung function test to confirm the diagnosis. In addition, for children with respiratory diseases such as asthma and pneumonia, regular lung function tests are also an important means of evaluating the condition and adjusting the treatment plan.

Pulmonary function tests play an important role for children. First, they can help doctors accurately diagnose respiratory diseases, such as asthma and interstitial lung disease, to avoid misdiagnosis and missed diagnosis. Second, through pulmonary function tests, doctors can assess the severity of children's illnesses and provide a basis for developing personalized treatment plans. In addition, pulmonary function tests can also be used as a means of evaluating treatment effectiveness to ensure that children receive the best treatment results.

3. Childhood Asthma and Pulmonary Function Test

Asthma is one of the common respiratory diseases in children, characterized by recurrent wheezing, coughing, chest tightness and other symptoms. The pathogenesis of asthma is complex and diverse, involving genetic factors, environmental factors and other aspects. Since asthma is a chronic disease that requires long-term management and treatment, regular lung function tests are particularly important for children with asthma.

The lung function of children with asthma has obvious characteristics, mainly manifested as increased airway reactivity and airflow obstruction. These changes can be directly reflected in lung function tests. Through forced expiratory lung function tests or pulse oscillation lung function tests, doctors can evaluate the degree of airway obstruction and reversible changes in children with asthma, providing a basis for formulating treatment plans and adjusting drug dosages.

In addition, pulmonary function tests can also help doctors grade and assess the condition of children with asthma. Based on the results of pulmonary function tests and clinical manifestations, doctors can classify the condition of children with asthma into different levels, such as mild, moderate, and severe, in order to develop a more accurate treatment plan. It should be noted that although pulmonary function tests play an important role in the diagnosis and management of asthma, pulmonary function tests are not suitable in all cases. For example, during the acute infection period of the disease, especially during infectious diseases, or in the presence of other serious complications, pulmonary function tests should be postponed to avoid aggravating the condition or causing adverse consequences.