Respiratory reactance in children aged three to five years with postinfectious bronchiolitis obliterans is higher than in those with asthma

Advances in Pediatric Lung Function Testing Techniques

For decades spirometry has been the benchmark test for capturing lung function in children but its recognized limitations required the development of other techniques. This article introduces novel techniques in lung function assessment for pediatric patients, including multiple breath washout, impulse oscillometry, structured light plethysmography, and electrical impedance tomography, and common themes in interpreting the results. Challenges include standardization, reference data, and clinical integration of these innovative tools. Further research is ongoing to optimize these tests for clinical use, especially in diverse populations and pediatric settings.

Pulmonary function in children with persistent tachypnea of infancy

BACKGROUND

Data on the prevalence and type of lung function impairment in preschool and school-aged children previously diagnosed with persistent tachypnea of infancy (PTI) are scarce. Therefore, this study aims to assess pulmonary function in this age group.

METHODS

Children diagnosed with PTI over 3 years old were admitted for follow-up visits and healthy controls were enrolled. The study group included children who were able to complete pulmonary function tests (PFTs). Medical history, physical examination, and pulmonary function (spirometry, body plethysmography, impulse oscillometry, nitrogen multiple breath washout test, diffusing capacity for carbon monoxide [DL_CO ]) were assessed.

RESULTS

Thirty-seven children (26 boys, 11 girls; median age: 5.6 years) diagnosed with PTI and 37 healthy controls were recruited. Forced expiratory volume in 1 s and forced vital capacity were significantly lower (-1.12 vs. 0.48, p = 0.002 and -0.83 vs. 0.31, p = 0.009, respectively); respiratory resistance at 5 Hz (0.06 vs. -0.62, p = 0.003), resonant frequency (1.86 vs. 1.36, p = 0.04), residual volume (RV) (2.34 vs. -1.2, p < 0.0001), RV%TLC (total lung capacity) (2.63 vs. -0.72, p < 0.0001), and specific airway resistance (5.4 vs. 2.59, p = 0.04) were significantly higher in PTI patients as compared with controls (data were presented as median z-score). Air trapping was found in 60.0%, and abnormally high lung clearance index and DL_CO  were found in 73.3% and 90.9% of PTI patients, respectively.

CONCLUSIONS

This study demonstrated that lung function is affected in most children with PTI. PFTs showed that peripheral airways are the major zone of functional impairment.

Airwave oscillometry and spirometry in children with asthma or wheeze

OBJECTIVE

Lung function testing is used in diagnosing asthma and assessing asthma control. Spirometry is most commonly used, but younger children can find performing this test challenging. Non-volitional tests such as airwave oscillometry (AOS) may be helpful in that population. We compared the success of spirometry and AOS in assessing bronchodilator responsiveness in children.

METHODS

AOS was conducted alongside routine lung function testing. Resistance at 5 Hz (R5), the difference between the resistance at 5 and 20 Hz (R5-20) and the area under the reactance curve (AX) were assessed. Patients between 5 and 16 years old attending clinic with wheeze or asthma were assessed. Patients performed AOS, followed by spirometry and were then given 400 µg salbutamol; the tests were repeated 15 minutes later.

RESULTS

Lung function testing was performed in 47 children of whom 46 (98%) and 32 (68%) performed acceptable baseline oscillometry and spirometry, respectively (p < 0.001). Children unable to perform acceptable spirometry were younger (7.35, range: 5.4-10.3 years) than those who could (10.4, range: 5.5-16.9 years), p < 0.001. The baseline z-scores of AOS R5 correlated with FEV₁ (r = 0.499, p = 0.004), FEF₇₅ (r = 0.617, p < 0.001), and FEV₁/FVC (r = 0.618, p < 0.001). There was a positive bronchodilator response assessed by spirometry (change in FEV₁ ≥ 12%) in eight children which corresponded to a change in R5 of 36% (range: 30%-50%) and a change in X5 of 39% (range: 15%-54%).

CONCLUSIONS

Oscillometry is a useful adjunct to spirometry in assessing young asthmatic children's lung function. The degree of airway obstruction, however, might affect the comparability of the results of the two techniques.

Clinical significance and applications of oscillometry

Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunction and the effects of environmental exposures. However, despite great promise as a useful clinical tool, we identify a number of areas in which more evidence of clinical utility is needed before oscillometry becomes routinely used for diagnosing or monitoring respiratory disease.

This paper provides a current review of the interpretation, clinical significance and application of oscillometry in respiratory medicine, with special emphasis on limitations of evidence and suggestions for future research.https://bit.ly/3GQPViA

The association of lung function changes with outcomes in children with bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a life-threatening respiratory complication of allogeneic hematopoietic stem cell transplantation (HSCT). Although pulmonary function testing is crucial for monitoring BOS, little information exists on the association of these test results with outcomes in children with BOS.

OBJECTIVES

The purpose of this study was to determine the correlation between changes in lung function after BOS diagnosis and long-term outcomes.

METHODS

A total of 428 children underwent allogeneic HSCT from January 2006 to December 2017 at Asan Medical Center. Twenty-three (5.4%) were diagnosed with BOS after allogeneic HSCT, and their clinical data were reviewed. Twenty-one subjects underwent regular pulmonary function testing for 24 months after BOS diagnosis.

RESULTS

Among the 21 children with BOS, 8 died, 5 underwent lung transplantation (TPL), and 15 required oxygen (O₂ ) therapy. The FEV₁ % predicted (pred), FVC% pred, and FEF_25%-75% pred were 37.8 ± 12.7% (mean ± SD), 62.2 ± 16.2%, and 16.4 ± 9.6%, respectively, at the time of BOS diagnosis. Changes in the FEV₁ % pred were greater in the death and lung TPL groups (-24.8 ± 22.3%) than in the survival without lung TPL group (5.7 ± 21.8%) and greater in the O₂ therapy (-19.4 ± 23.4%) group than in the group without O₂ therapy (14.2 ± 20.0%) during the first 3 months after BOS diagnosis.

CONCLUSION

The change in FEV₁ during the first 3 months after BOS diagnosis correlated with outcomes including survival, lung TPL, and O₂ therapy. These results suggest that more active intervention in the first 3 months after BOS diagnosis may be needed to improve prognosis.

Clinical observation of the effect of modified Ginseng-Schisandra decoction (MGSD) on trace elements and immune function in children with spleen deficiency syndrome after recurrent respiratory tract infection (RRTI): a randomized controlled trial

BACKGROUND

Recurrent respiratory tract infection (RRTI) is common disease in childhood, and the incidence rate is increasing in China. The cause is complex, which is related to the physiological characteristics of children's respiratory system and the immature immune function, lack of trace elements and environmental pollution. Immunomodulators and antibiotics are often used to treat RRTI, but the clinical efficacy still needs to be improved. Chinese medicine has unique advantages in the treatment of RRTI. In the clinical treatment of RRTI, the authors often use modified Ginseng-Schisandra decoction (MGSD). In order to study the clinical effect of MGSD on serum trace elements and immune function in children with spleen deficiency syndrome after RRTI, we conducted this clinical observation.

METHODS

This is a single-center randomized trial with two parallel groups. Eighty children who developed spleen deficiency syndrome following RRTI were randomly and equally divided into a control group and an observation group. The control group was given Medilac-vita and the observation group was given MGSD. The participants, care givers, and those assessing the outcomes were blinded to group assignment. The treatment course was 4 weeks. Clinical efficacy, traditional Chinese medicine (TCM) syndrome scores, humoral immunity, and trace element index values before and after treatment were compared between the two groups of children.

RESULTS

The trial was finished. The total effective rate of the observation group (n=40, 95%) was significantly higher than control group (n=40, 65%) (P<0.05). After treatment, the TCM syndrome scores of the two groups were reduced compared to those before treatment, while the serum immunoglobulin A and G levels were increased (P<0.05); however, the observation group had significantly lower TCM syndrome scores than the control group. Significant improvements in serum immunoglobulins (IgA and IgG) levels, T lymphocyte subsets (CD3⁺, CD4⁺, and CD4⁺/CD8⁺), and trace elements (Zn and Fe) indicators were observed in the observation group compared to the control group (P<0.05).

CONCLUSIONS

The application of MGSD in the treatment of children with spleen deficiency syndrome after RRTI has a definite clinical effect. MGSD can effectively improve the immune function of the patients and the content of the trace elements iron and zinc, and thus has potential value for promotion and application.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2100047128.

Assessment of pulmonary function by impulse oscillometry and spirometry in children with type 1 diabetes mellitus

AIM

To assess the lung functions with impulse oscillometry (IOS) and spirometry in children with type 1 diabetes mellitus (T1DM).

METHODS

Fifty-one children with T1DM, and sex- and age-matched 53 healthy control (HC) subjects were included in this study. Demographic, clinical, and laboratory characteristics of the subjects were recorded and their pulmonary functions were analyzed by IOS and spirometry.

RESULTS

In IOS, zR5, zR10, and zR20 levels were higher in children with T1DM compared with HCs (P = .019, P = .017, and P = .002, respectively). In spirometry, zFEF75 and zFEF25-75 were lower in children with T1DM compared with HCs (P = .025, P = .001, respectively). In IOS, zR5-20 (P = .008, P = .005, respectively) and zAX (P = .013, P = .009, respectively) were significantly lower in good-controlled group compared with moderate- and poor-controlled group. In spirometry, zFEF25-75 was significantly higher in good-controlled group compared with moderate- and poor-controlled group (P = .005, P = .009, respectively). HbA1c was positively correlated with zR5-20 value (r = .339; P = .017) in male children with T1DM. The duration of the disease was positively correlated with zR5-20 (r = .290; P = .043) and zFres (r = .358; P = .010). According to the receiver operating characteristic curve analysis to estimate optimal cut-offs to discriminate good control level of T1DM (HbA1c < 7%), a zR5-20 ≤ 2.28 demonstrated a 75.0% sensitivity and 82.9% specificity, with an area under the curve of 0.805 ([confidence interval, 0.615-0.995]; P = .007).

CONCLUSIONS

This study showed subclinical impairment of lung functions which is associated with disease duration and the degree of metabolic control in children with T1DM.

Pulmonary function testing in children's interstitial lung disease

The use of pulmonary function tests (PFTs) has been widely described in airway diseases like asthma and cystic fibrosis, but for children's interstitial lung disease (chILD), which encompasses a broad spectrum of pathologies, the usefulness of PFTs is still undetermined, despite widespread use in adult interstitial lung disease. A literature review was initiated by the COST/Enter chILD working group aiming to describe published studies, to identify gaps in knowledge and to propose future research goals in regard to spirometry, whole-body plethysmography, infant and pre-school PFTs, measurement of diffusing capacity, multiple breath washout and cardiopulmonary exercise tests in chILD. The search revealed a limited number of papers published in the past three decades, of which the majority were descriptive and did not report pulmonary function as the main outcome.PFTs may be useful in different stages of management of children with suspected or confirmed chILD, but the chILD spectrum is diverse and includes a heterogeneous patient group in all ages. Research studies in well-defined patient cohorts are needed to establish which PFT and outcomes are most relevant for diagnosis, evaluation of disease severity and course, and monitoring individual conditions both for improvement in clinical care and as end-points in future randomised controlled trials.

Postinfectious bronchiolitis obliterans masked by misdiagnosis as asthma

OBJECTIVES

Asthma and postinfectious bronchiolitis obliterans (PIBO) have similar clinical findings, and PIBO may be misdiagnosed with asthma. This study aimed to determine the clinical features of PIBO in children and the causes of delay in its diagnosis.

METHODS

We retrospectively evaluated all patients diagnosed with PIBO in four pediatric pulmonology centers between 2007 and 2018. In total, 64 PIBO patients were retrospectively reviewed. We compared the clinical and laboratory differences between PIBO patients who had initially been misdiagnosed with asthma and correctly diagnosed with PIBO.

RESULTS

Of the 64 patients, 22 (34.4%) had initially been misdiagnosed with asthma. Adenovirus was the most common infectious agent in children. The age upon diagnosis was older, and the symptom duration was significantly longer in patients misdiagnosed with asthma (P < .05). There were no statistical differences in terms of sex, history of prematurity, duration of hospitalization, treatment, history of oxygen or mechanical ventilation support, pulmonary function test (PFT) results and asthma-predisposing findings between the two groups (P > .05).

CONCLUSIONS

Patients with PIBO who had initially been misdiagnosed with asthma were correctly diagnosed at older ages and had longer symptom duration. Asthma may mask PIBO diagnosis by the similarity of symptoms and the clinical response to inhaled β2-agonist or steroid treatment. PFTs may not help clinicians because of the age of children. The delay in the diagnosis of PIBO is probably attributable to the fact that some clinicians fail to include PIBO in the differential diagnosis when there is no clinical response to asthma medication.

Diagnosing and managing bronchiolitis obliterans in children

INTRODUCTION

Bronchiolitis obliterans (BO) is a chronic and irreversible obstructive lung disease leading to the obstruction and/or obliteration of the small airways. Three main BO entities are distinguished: post-infectious BO (PIBO); BO post lung transplantation; and BO after bone marrow transplantation (BMT) or hematopoietic stem cell transplantation (HSCT). All three entities are separate, however, there are similarities in histopathological characteristics and possibly in aspects of the development pathway. Areas covered: We review current evidence of bronchiolitis obliterans diagnosis and management in children. The diagnosis of BO is usually based on a combination of history, clinical and radiological findings, although lung biopsy and histopathology remain the gold standard approaches to confirm BO. Expert opinion: At present, we do not have a clear understanding of the mechanisms of the development of BO and lack strong evidence for treatment. Although most BO in children is post-infectious, most of the current evidence for treatment originates from studies analyzing BO in adult lung transplant and HSCT patients. BO management requires multidisciplinary approach and care in specialized centers.

Post-infectious bronchiolitis obliterans

Bronchiolitis obliterans is a rare and severe chronic lung disease resulting from a lower respiratory tract lesion. It may occur after a bone marrow or lung transplantation, infectious diseases, or less frequently after inhaling toxic substances or after connective tissue diseases. Pathology, pathogenesis, and molecular biology, as well as the best treatment of bronchiolitis obliterans, remain the subject of ongoing research. This review discusses our current knowledge of different areas of bronchiolitis obliterans associated with infectious lesions.