The impact of infections caused by bacteria, especially Gram‐negative, on the progression of lung disease in cystic fibrosis is well established. Decline in pulmonary function commence already at early age. In this group of patients, the lung clearance index seems to be a better marker than FEV1 allowing non‐invasive monitoring of changes in small airways. The aim of this study was to investigate the association between the microbiological status and LCI derived from multiple breath washout (MBW) technique as well as FEV1 and FVC in children suffering from cystic fibrosis. Over the 1‐year recruitment period, 136 CF patients aged 5‐18 with: Staphylococcus aureus (n‐27), Pseudomonas aeruginosa (first time (n‐27), intermittent (n‐9), and chronic (34) infection), Aspergillus fumigatus (n‐6) and without pathogenic flora (n‐33) were included in the study. Patients had performed a spirometry and MBW test during the visit at outpatient clinic. The study showed that the lung clearance index in patients infected with Aspergillus fumigatus was significantly higher (P < 0.05) than in those with normal throat flora. There was also statistically significant differences in the lung clearance index obtained in subjects with chronic Pseudomonas aeruginosa infection and those with first Pseudomonas aeruginosa infection (P < 0.05). Furthermore, significant statistical differences (P < 0.05) were observed between the groups of patients with chronic Pseudomonas aeruginosa infection FEV1 > 70% and FEV1 < 70%. In conclusion, LCI was associated with microbiological status of CF patients. Chronic lung infections, especially Aspergillus fumigatus and Pseudomonas aeruginosa, were associated with increased LCI. Early eradication of pathological flora positively affects the maintenance of lower LCI.

(1) Background: Pulmonary exacerbation (PEx) is one of the main factors affecting the quality of life and life expectancy in patients with cystic fibrosis (CF). Our study aimed to evaluate the change in selected pulmonary function parameters, including lung clearance index (LCI), in patients with CF diagnosed with PEx. (2) Methods: We enrolled 40 children with CF aged 6–17. They performed spirometry and multiple breath nitrogen washout (MBNW) tests during a stable condition period at the beginning and the end of intravenous antibiotic treatment. (3) Results: LCI increased by 65% and FEV1 decreased by ≥10% in 40% of patients with CF during PEx. An absolute change in LCI between a stable condition period and PEx was 1.05 (±1.92) units, which corresponds to a relative change of 11.48% (±18.61) of the baseline. The relative decrease in FEV1 was −9.22% (±12.00) and the z-score was −0.67 (±1.13). After the PEx treatment, FEV1 increased by 11.05% (±9.04) on average, whereas LCI decreased by 1.21 ± 1.59 units on average, which represented 9.42% ± 11.40 compared to the value at the beginning of PEx. (4) Conclusions: The change in LCI captures a higher proportion of events with functional impairment than FEV1 in school-age children with CF.

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IntroductionPseudomonas aeruginosa cross‐infections are related to increased morbidity and mortality in cystic fibrosis (CF).ObjectivesThe aim of the study was to evaluate the incidence of cross‐infections with P. aeruginosa in children with CF.MethodologyCF patients from whom at least one P. aeruginosa strain had been isolated were included in the study. The strain genotyping was performed using pulse‐field gel electrophoresis. The history of contacts between patients was established based on questionnaires.ResultsThe study group consisted of 75 patients (aged 1.0‐19.2 years) and the material included 170 P. aeruginosa strains. Cross‐infections occurred in a group of 26 patients. In this group, the risk of the predicted occurrence of forced expiratory volume in 1 second ≤ 70% was five times greater and the risk of longer cumulative hospitalization time for intravenous antibiotic therapy (>14 days/year) was almost five times greater. In the clonal groups of strains, the multidrug‐resistance rate was significantly higher than in other groups. In 2011, all tested strains were susceptible to colistin, whereas in 2012, three strains from the largest clonal group showed high levels of resistance to colistin.ConclusionCross‐infections with P. aeruginosa occurred in our group of patients and were associated with poor clinical outcomes. Antimicrobial resistance rate in the strains isolated from such infections was significantly higher, and this included three strains resistant to colistin.

IntroductionIn cystic fibrosis (CF), pathological lung changes begin early in life. The technological progress currently gives many diagnostic possibilities. However, pulmonary function testing in children remains problematic.ObjectivesOur study aimed to correlate the results of impulse oscillometry (IOS) with those of multiple breath nitrogen washout (MBNW) in our pediatric CF population. We also compared those parameters between the groups with and without spirometric features of obturation.MethodsWe collected 150 pulmonary function test sets, including spirometry, IOS, and MBNW in patients with CF aged 12.08 ± 3.85 years [6–18]. The study group was divided into two subgroups: IA (without obturation) and IB (with obturation). We also compared Sacin, Scond, and oscillometry parameters of 20 patients aged 14–18 years who reached the appropriate tidal volume (VT) during MBNW.ResultsStatistical analysis showed a negative correlation between lung clearance index (LCI) and spimoetric parameters. Comparison of subgroups IA (n = 102) and IB (n = 48) indicated a statistically significant difference in LCI (p &lt; 0.001) and FEV1z-score (p &lt; 0.001), FEV1% pred (p &lt; 0.001), MEF25z-score (p &lt; 0.001), MEF50 z-score (p &lt; 0.001), MEF75 z-score (p &lt; 0.001), R5% pred (p &lt; 0.05), and R20% pred (p &lt; 0.01). LCI higher than 7.91 was found in 75.33% of the study group, in subgroup IB—91.67%, and IA−67.6%.ConclusionsLCI derived from MBNW may be a better tool than IOS for assessing pulmonary function in patients with CF, particularly those who cannot perform spirometry.