Lung Function in Preschool Children in Low and Middle Income Countries: An Under-Represented Potential Tool to Strengthen Child Health

[Application of interrupter resistance pulmonary function testing in the diagnosis of asthma in preschool children: a single-center study]

OBJECTIVES

To investigate the value of interrupter resistance (Rint) pulmonary function testing in the diagnosis of asthma in preschool children, and to compare the significance of Rint pulmonary function testing versus impulse oscillometry (IOS) in the diagnosis of asthma.

METHODS

A prospective study was conducted among 108 children with recurrent wheezing, aged 4 to <6 years, who were admitted from July 2022 to November 2023. According to the treatment outcome, they were divided into an asthmatic group (61 children) and a non-asthmatic group (47 children). Rint pulmonary function parameters and IOS parameters were analyzed for both groups, and the two tests were compared in terms of feasibility and diagnostic value.

RESULTS

Compared with the non-asthmatic group, the asthmatic group had significantly higher percentage of actual measured value to predicted value for Rint and percent changes in the measured value and predicted value of Rint (P<0.05). The receiver operating characteristic curve analysis showed that the percent change in the predicted value of Rint had an optimal cut-off value of 32.0% in the diagnosis of asthma in preschool children, with an area under the curve (AUC) of 0.705, a sensitivity of 41.0%, and a specificity of 91.5% (P<0.05). In terms of the degree of completion, 18 children (16.7%) failed to complete the IOS test, but they could successfully complete Rint pulmonary function testing with good quality control. Rint pulmonary function testing and IOS had a similar area under the curve in the diagnosis of asthma in preschool children (P>0.05).

CONCLUSIONS

Rint pulmonary function testing can be used to assist in the diagnosis of asthma in preschool children, with a similar diagnostic value to IOS and a relatively high level of feasibility. A percent change of ≥32% in the predicted value of Rint in the bronchial dilation test can be used as a cut-off value for the diagnosis of asthma in preschool children.

Post-tuberculosis lung disease in children and adolescents: A scoping review of definitions, measuring tools, and research gaps

Tuberculosis (TB) survivors, especially children and adolescents, can develop chronic respiratory problems called post-tuberculosis lung disease (PTLD). We conducted a scoping review to identify the current knowledge gaps on PTLD definitions, measuring tools, and research specific to this age group. We searched MEDLINE, EMBASE, Global Health, CINAHL, and Web of Science for studies published between January 1, 2000, and March 1, 2024, and identified 16 studies. Our review found that no consistent definition of PTLD was used in the studies, and the measurement tools used varied widely. Moreover, there was a lack of research on children under five years old, who are disproportionately affected by TB. Also, symptom screening tools designed for adults were frequently used in these studies, raising concerns about their accuracy in detecting PTLD in children and adolescents. Several critical research gaps require attention to improve our understanding and treatment of PTLD. Firstly, the use of inconsistent definitions of PTLD across studies makes it challenging to compare research findings and gain a clear understanding of the condition. Therefore, we need to include an objective measurement of respiratory health, such as a comprehensive post-TB lung function assessment for children and adolescents. It is also crucial to determine the optimal timing and frequency of post-TB assessments for effective PTLD detection. Furthermore, we need more knowledge of the modifiable risk factors for PTLD. The scarcity of prospective studies makes it difficult to establish causality and track the long-term course of the disease in children and adolescents. Finally, current approaches to PTLD management often fail to consider patient-reported outcomes and strategies for social support. Addressing these research gaps in future studies can improve our understanding and management of paediatric PTLD, leading to better long-term health outcomes for this vulnerable population.

Impulse oscillometry bronchodilator response in preschool children

BACKGROUND

In preschoolers, performing an acceptable spirometry and measuring bronchodilator response (BDR) is challenging; in this context, impulse oscillometry (IOS) represents a valid alternative. However, more studies on the standardization of BDR for IOS in young children are required.

OBJECTIVE

The objective of the study was to identify optimal thresholds to define a positive BDR test with IOS in preschoolers with suspected asthma.

METHODS

Children aged 3-6 years with suspected asthma and their lung function investigated with both IOS and spirometry pre- and post-BDR were retrospectively analyzed. The spirometric BDR was defined as positive when the change of FEV1 was ≥12% or ≥200 mL. The oscillometric BDR was defined as positive in case of change of at least -40% in R5, +50% in X5, and -80% in AX.

RESULTS

Among 72 patients, 36 (age 5.2 ± 1 years; 64% boys) were selected for the subsequent analysis according to ATS/ERS quality criteria of measurements; specifically, 19 patients did not meet IOS and 36 did not meet spirometry criteria. The spirometric BDR was found positive in seven subjects (19.4%); conversely, a positive oscillometric BDR was identified in four patients (11.1%). No patient presented a positive BDR response with both methods. In IOS, the mean decrease in R5 and AX was 19.9% ± 10% and 44% ± 22.1%, and the mean increase in X5 was 23.3% ± 17.8%, respectively. A decrease in R5 of 25.7% (AUC 0.77, p = .03) and an increase in X5 of 25.7% (AUC 0.75, p = .04) showed the best combination of sensitivity and specificity to detect an increase of FEV1 ≥ 12% and/or ≥200 mL.

CONCLUSION

The IOS represents a valid alternative to spirometry to measure BDR in preschool children and should be the gold standard in this age group. We are considering a decrease of 26% in R5 and an increase of 26% in X5 as diagnostic threshold for BDR.