Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

What diagnostic tests are available for respiratory infections or pulmonary exacerbations in cystic fibrosis: A scoping literature review

A scoping review methodological framework formed the basis of this review. A search of two electronic databases captured relevant literature published from 2013. 1184 articles were screened, 200 of which met inclusion criteria. Included studies were categorised as tests for either respiratory infections OR pulmonary exacerbations. Data were extracted to ascertain test type, sample type, and indication of use for each test type. For infection, culture is the most common testing method, particularly for bacterial infections, whereas PCR is utilised more for the diagnosis of viral infections. Spirometry tests, indicating lung function, facilitate respiratory infection diagnoses. There is no clear definition of what an exacerbation is in persons with CF. A clinical checklist with risk criteria can determine if a patient is experiencing an exacerbation event, however the diagnosis is clinician-led and will vary between individuals. Fuchs criteria are one of the most frequently used tests to assess signs and symptoms of exacerbation in persons with CF. This scoping review highlights the development of home monitoring tests to facilitate earlier and easier diagnoses, and the identification of novel biomarkers for indication of infections/exacerbations as areas of current research and development. Research is particularly prevalent regarding exhaled breath condensate and volatile organic compounds as an alternative sampling/biomarker respectively for infection diagnosis. Whilst there are a wide range of tests available for diagnosing respiratory infections and/or exacerbations, these are typically used clinically in combination to ensure a rapid, accurate diagnosis which will ultimately benefit both the patient and clinician.

Lung ultrasound evaluation in people with cystic fibrosis: A new approach in the pulmonology outpatient clinic

BACKGROUND

Cystic fibrosis (CF) is a genetic disease that causes progressive lung disease with major impact on the quality of life. Lung ultrasound (LUS) allows to assess the lung involvement through the artefacts analysis and is increasingly used in children but is not yet used to monitor people with CF(pwCF). The main aim of this study was to describe the LUS pattern of pwCF during their routinary check-up visit. The secondary objective was to correlate the LUS findings with pulmonary function indices.

METHODS

We performed a cross-sectional observational study, enrolling adolescents and young adults with CF. Each patient underwent clinical assessment, measurement of SpO2, assessment of lung function by spirometry and LUS.

RESULTS

Twenty-nine subjects with CF were included. The most frequent alterations were consolidations (72.4%) located in the left apical anterior and right apical posterior regions followed by interstitial syndrome (65.5%). The 41.4% of cases presented the lingula involvement, characterized by a consolidation with static air bronchogram, and 55.2% showed pleural irregularity mainly in the posterior apical regions. A significant correlation was found between the LUS total score and spirometric indices: FEV1 (p = .003), FVC (p = .002), Tiffenau Index <80% (p = .014), and FEF 25-75 (p = .004).

CONCLUSIONS

Our study describes LUS findings in pwCF. It also showed a correlation between LUS score and the patients' lung function measured by spirometric indices. We conclude that LUS may be useful in routine monitoring of pwCF in combination with clinical and spirometric assessment.

Electronic home monitoring of children with cystic fibrosis to detect and treat acute pulmonary exacerbations and its effect on 1-year FEV1

BACKGROUND

We aimed to investigate the effect of the use of electronic home spirometry in children with cystic fibrosis (CF) on 1-year FEV1 (% predicted, pp) change.

METHODS

This is a randomised, one-year prospective study including children with CF between 6 and 18 years of age. Subjects were randomised into home spirometry group (HSG) and usual care group (UCG). Children in HSG performed two pulmonary function tests (PFT) per week. Data regarding acute pulmonary exacerbations (PEx) was obtained from patients' records. At baseline and 12th month, health related quality of life questionnaire for CF patients (CFQ-R) and lung clearance index (LCI) were performed.

RESULTS

Sixty children were recruited with a median (IQR) age of 13.3 (11.4-15.4) years. Absolute change in FEV1pp from baseline to 12th month as median (IQR) was +1% (-6.75-9.75) in HSG and -2.50% (-7.50-3.25) in UCG (p = 0.10). Sensitivity analysis including only adherent children in HSG (n = 22), yielded an increase of 5% (-3.50-12) in HSG and a decrease of 2.50% (-7.50-3.25) in UCG (p = 0.009). A total of 29 (96.7%) subjects in HSG and 23 (76.7%) in UCG had PEx (p = 0.05). Absolute change in median (IQR) LCI2.5 from baseline to the 12th month was -1.6 [-2.9-0] (p<0.001) in HSG and -1.5 [-2.8-(-0.6)] (p<0.001) in UCG (p = 0.94). There was a significant increase in the social domain of the CFQ-R in HSG (from 59.1 to 76.2, p = 0.01).

CONCLUSIONS

Electronic home monitoring of children with CF by spirometry may result in improvement in lung function.

Delivering a New Future for People With Cystic Fibrosis

Treatment, prognosis, and quality of life for people with cystic fibrosis (CF) have improved steadily since the initial description of the disease, but most dramatically in the past decade. In 2021, the median predicted survival increased to 53 years, compared with 17 years in 1970. The recent improvement in outcomes is attributable to the advent of cystic fibrosis transmembrane regulator (CFTR) modulators, small molecules that enhance the function of defective CFTR protein. The first CFTR modulator, ivacaftor, received Food and Drug Administration approval in 2011 to treat a single CFTR variant, comprising only 4% of those affected by CF. With the demonstration of efficacy, drug approval has been expanded to other variants. Multiple CFTR modulators used in combination with ivacaftor augment efficacy and increase the number of CFTR variants amenable to therapy. Approval of elexecaftor/tezecaftor/ivacaftor in 2019 increased the number of individuals who could benefit from highly effective modulator therapy (HEMT) to ∼90% of the CF population in the United States. HEMT has been dramatically effective, with overall improvements in lung function, quality of life, nutritional status, and, in women, increased fertility. HEMT may delay the onset of other CF-related comorbidities. Although off-target effects, including hepatotoxicity, drug-drug interactions, and putative mental health issues can complicate use, modulator therapy has been generally well tolerated. Ten percent of people with CF have variants that are not amenable to modulator treatment. HEMT, despite its great cost and limited global access, has brought legitimate hope and changed the lives of a significant majority of individuals and families affected by CF in North America.

Factors associated with lung function response with oral antibiotic treatment of pulmonary exacerbations in cystic fibrosis

Pulmonary exacerbations treated with oral antibiotics (oPEx) have a significant effect on lung function decline in people with cystic fibrosis (CF). However, factors associated with lung function response with oPExs are not well defined. We performed a retrospective cohort study of pediatric and adult patients with CF followed in the Toronto CF Database. Lung function response was measured both as the change in forced expiratory volume in 1 second (FEV1) from Day 0 of antibiotic therapy to end of treatment as well as from baseline to end of treatment. Drop from baseline to Day 0 FEV1 was strongly associated with lung function response (p<0.001). Greater FEV1 improvements were associated with longer antibiotic treatment durations. Older, female patients had less improvements in FEV1 at end of treatment compared to younger, male patients.

How Does the Corrected Exhalyzer Software Change the Predictive Value of LCI in Pulmonary Exacerbations in Children with Cystic Fibrosis?

Aim: Recently, the most commonly used for multiple breath washout device, the Exhalyzer D, has been shown to overestimate lung clearance index (LCI) results due to a software error. Our study aimed to compare the predictive values of LCI in the CF pulmonary exacerbations (PE) calculated with the updated (3.3.1) and the previous (3.2.1) version of the Spiroware software. Materials and Methods: The measurements were performed during 259 visits in CF pediatric patients. We used 39ΔPE pairs (PE preceded by stable visit) and 138ΔS pairs (stable visit preceded by stable visit) to compare the LCI changes during PE. The areas under the receiver operating curves (AUC^ROC) and odds ratios were calculated based on the differences between ΔPEs and ΔSs. The exacerbation risk was estimated using a logistic regression model with generalized estimating equations (GEE). Results: There were statistically significant differences in LCI 2.5% median values measured using the two versions of the software in the stable condition but not during PE. The AUC^ROC for changes between the two consecutive visits for LCI did not change significantly using the updated Spiroware software. Conclusions: Despite the lower median values, using the recalculated LCI values does not influence the diagnostic accuracy of this parameter in CF PE.

Lung Ultrasound in the Evaluation of Lung Disease Severity in Children with Clinically Stable Cystic Fibrosis: A Prospective Cross-Sectional Study

With the increasing longevity of cystic fibrosis (CF), there is a growing need to minimise exposure to ionising radiation in patients who undergo regular imaging tests while monitoring the course of the lung disease. This study aimed to define the role of lung ultrasounds (LUS) in the evaluation of lung disease severity in children with clinically stable CF. LUS was performed on 131 patients aged 5 weeks to 18 years (study group) and in 32 healthy children of an equivalent age range (control group). Additionally, an interobserver study was performed on 38 patients from the study group. In CF patients, the following ultrasound signs were identified: I-lines; Z-lines; single, numerous and confluent B-lines; Am-lines; small and major consolidations; pleural line abnormalities and small amounts of pleural fluid. The obtained results were evaluated against an original ultrasound score. LUS results were correlated with the results of chest X-ray (CXR) [very high], pulmonary function tests (PFTs) [high] and microbiological status [significant]. The interobserver study showed very good agreement between investigators. We conclude that LUS is a useful test in the evaluation of CF lung disease severity compared to routinely used methods. With appropriate standardisation, LUS is highly reproducible.

Distribution and Characteristics of Bacteria Isolated from Cystic Fibrosis Patients with Pulmonary Exacerbation

Background

Cystic fibrosis (CF) is an inherited recessive disorder characterized by recurrent and persistent pulmonary infections, resulting in lung function deterioration and early mortality.

Methods

A cross-sectional study was conducted on the bacterial profile and antibiotic resistance pattern of 103 respiratory specimens from CF patients with signs of pulmonary exacerbation. Antibiotic susceptibility testing and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa isolates were performed by the Kirby-Bauer disc diffusion method and microtiter plate assay, respectively. Molecular typing of S. aureus and P. aeruginosa isolates was carried out by spa typing and repetitive extragenic palindromic element PCR.

Results

In a total of 129 isolates, the most prevalent organisms were S. aureus (55.3%) and P. aeruginosa (41.7%). Other less prevalent bacterial isolates include coagulase-negative staphylococci, Escherichia coli, klebsiella spp., Enterobacter spp., and Achromobacter xylosoxidans. The highest rate of resistance for S. aureus was observed to azithromycin and erythromycin (80%), ciprofloxacin (52.3%), clindamycin (44.6%) and tetracycline (43%). Twenty percent of S. aureus isolates were methicillin-resistant S. aureus (MRSA) and 47.6% were MDR S. aureus. For P. aeruginosa isolates the highest resistance was to cefepime (38.3%) and levofloxacin (33.3%) and 20% showed MDR phenotype.

Conclusion

Our study demonstrated a significant decline in the prevalence of P. aeruginosa infections in comparison to previous studies. We found S. aureus to be more prevalent in younger patients, whereas mucoid P. aeruginosa showed a shift in prevalence toward older ages. Molecular typing methods showed great diversity between isolates.

Management of respiratory tract exacerbations in people with cystic fibrosis: Focus on imaging

Respiratory tract exacerbations play a crucial role in progressive lung damage of people with cystic fibrosis, representing a major determinant in the loss of functional lung tissue, quality of life and patient survival. Detection and monitoring of respiratory tract exacerbations are challenging for clinicians, since under- and over-treatment convey several risks for the patient. Although various diagnostic and monitoring tools are available, their implementation is hampered by the current definition of respiratory tract exacerbation, which lacks objective "cut-offs" for clinical and lung function parameters. In particular, the latter shows a large variability, making the current 10% change in spirometry outcomes an unreliable threshold to detect exacerbation. Moreover, spirometry cannot be reliably performed in preschool children and new emerging tools, such as the forced oscillation technique, are still complementary and need more validation. Therefore, lung imaging is a key in providing respiratory tract exacerbation-related structural and functional information. However, imaging encompasses several diagnostic options, each with different advantages and limitations; for instance, conventional chest radiography, the most used radiological technique, may lack sensitivity and specificity in respiratory tract exacerbations diagnosis. Other methods, including computed tomography, positron emission tomography and magnetic resonance imaging, are limited by either radiation safety issues or the need for anesthesia in uncooperative patients. Finally, lung ultrasound has been proposed as a safe bedside option but it is highly operator-dependent and there is no strong evidence of its possible use during respiratory tract exacerbation. This review summarizes the clinical challenges of respiratory tract exacerbations in patients with cystic fibrosis with a special focus on imaging. Firstly, the definition of respiratory tract exacerbation is examined, while diagnostic and monitoring tools are briefly described to set the scene. This is followed by advantages and disadvantages of each imaging technique, concluding with a diagnostic imaging algorithm for disease monitoring during respiratory tract exacerbation in the cystic fibrosis patient.

Time Free From Hospitalization in Children and Adolescents With Cystic Fibrosis: Findings From FEV1, Lung Clearance Index and Peak Work Rate

BACKGROUND

An exercise test combined with a multiple breath washout nitrogen test (MBWN₂) may offer a comprehensive clinical evaluation of cystic fibrosis (CF) disease in children with normal spirometry. The purpose of the present study is to explore whether information derived from spirometry, MBWN₂, and exercise tests can help the CF multidisciplinary team to characterize time free from hospitalization due to pulmonary exacerbation (PE) in a cohort of pediatric patients with CF.

METHODS

This prospective observational study was carried out at the Lombardia Region Reference Center for Cystic Fibrosis in Milano, Italy. In 2015, we consecutively enrolled children and adolescents aged <18 years with spirometry, MBWN₂, and Godfrey exercise test performed during an outpatient visit.

RESULTS

Over a median follow-up time of 2.2 years (interquartile range [IQR], 2.01; 3.18), 28 patients aged between 13.0 and 17.4 years were included. When lung functions were outside the normal range, 50% of patients were hospitalized 4 months after the outpatient visit, and their response to exercise was abnormal (100%). Half of the individuals with normal forced expiratory volume in the first second (FEV₁) and abnormal lung clearance index (LCI) experienced the first hospital admission 9 months after the clinic visit, and 84.2% presented an abnormal response to exercise. Conversely, 15.8% had abnormal exercise responses when lung functions were considered normal, with half of the adolescents hospitalized at 11 months.

CONCLUSION

Maintaining ventilation homogeneity, along with a normal ability to sustain intense work, may have a positive impact on the burden of CF disease, here conceived as time free from hospitalization due to PE.