Evolution of pulmonary function during an acute exacerbation in hospitalized patients with cystic fibrosis

Treatment response to pulmonary exacerbation in primary ciliary dyskinesia

INTRODUCTION

Pulmonary exacerbation (Pex) are common in pediatric primary ciliary dyskinesia (PCD), however changes in forced expiratory volume in 1 s precent predicted (FEV1pp) during Pex are not well described.

AIM

To assess the evolution of FEV1pp during Pex and to define factors associated with failure to return to baseline lung function.

METHOD

This was a retrospective study of patients with PCD between 2010 and 2022. Pex were defined as the presence of increased respiratory symptoms treated with intravenous (IV) antibiotics. The main outcomes were the changes in FEV1 during therapy and the proportion of patients (responders) achieving ≥90% of baseline FEV1pp values at the end of admission.

RESULTS

The study included 52 Pex events in 28 children with PCD. The rate of responders was 32/41 (78%) at the end of admission. Nonresponse was associated with lower median body mass index (BMI) Z-score (-2.4 vs. -0.4, p < .01) and with a history of IV treated Pex in the previous year (p = .06). For the 22 Pex with available FEV1pp measurements at mid admission, the median relative and absolute improvement from admission to Day 7 was 9.1% and 6.2%, respectively (p- .001), and from Days 7 to 14 was 4.4% and 2.8%, respectively (p = .08).

CONCLUSION

In children with PCD treated with IV antibiotics, the majority of lung function recovery happens during the first week of IV therapy. Lower BMI was associated with nonresponse to therapy.

Acute exacerbations in children's interstitial lung disease

INTRODUCTION

Acute exacerbations (AEs) increase morbidity and mortality of patients with chronic pulmonary diseases. Little is known about the characteristics and impact of AEs on children's interstitial lung disease (chILD).

METHODS

The Kids Lung Register collected data on AEs, the clinical course and quality of life (patient-reported outcomes - PRO) of rare paediatric lung diseases. Characteristics of AEs were obtained.

RESULTS

Data of 2822 AEs and 2887 register visits of 719 patients with chILD were recorded. AEs were characterised by increased levels of dyspnoea (74.1%), increased respiratory rate (58.6%) and increased oxygen demand (57.4%). Mostly, infections (94.4%) were suspected causing an AE. AEs between two register visits revealed a decline in predicted FEV1 (median -1.6%, IQR -8.0 to 3.9; p=0.001), predicted FVC (median -1.8%, IQR -7.5 to 3.9; p=0.004), chILD-specific questionnaire (median -1.3%, IQR -3.6 to 4.5; p=0.034) and the physical health summary score (median -3.1%, IQR -15.6 to 4.3; p=0.005) compared with no AEs in between visits. During the median observational period of 2.5 years (IQR 1.2-4.6), 81 patients died. For 49 of these patients (60.5%), mortality was associated with an AE.

CONCLUSION

This is the first comprehensive study analysing the characteristics and impact on the clinical course of AEs in chILD. AEs have a significant and deleterious effect on the clinical course and health-related quality of life in chILD.

Abnormal Lung Clearance Index in Cystic Fibrosis Children with Normal FEV1 and Single-Breath Nitrogen Washout Test

Single- and multiple-breath washout tests (SBW and MBW) measure ventilation inhomogeneity, but the relationship between them is unclear. Forty-three subjects with cystic fibrosis (CF) and healthy controls (HC) 8-21 years of age were recruited (CF = 30 and HC = 13) and performed nitrogen MBW, vital capacity SBW, spirometry, and plethysmography. Mean phase III slope from SBW (SIII) and lung clearance index (LCI) were significantly different between CF and HC (p = 0.017 and p < 0.0001, respectively). Based on Pearson correlation, SIII and LCI showed strong correlation (ρ = 0.81, p < 0.0001). Both SIII and LCI significantly correlated with spirometry (all p < 0.05). Among CF subjects with normal FEV₁ (≥ 80%; n = 17), 76% (n = 13) had normal SIII but abnormal LCI. We conclude that LCI can be abnormal despite normal SIII and FEV₁ in CF children. Although LCI and SIII showed strong correlation, our results suggest that LCI is a better test to detect ventilation inhomogeneity in CF children with normal FEV₁.

Patterns of regional lung physiology in cystic fibrosis using ventilation magnetic resonance imaging and multiple-breath washout

Hyperpolarised helium-3 (3He) ventilation magnetic resonance imaging (MRI) and multiple-breath washout (MBW) are sensitive methods for detecting lung disease in cystic fibrosis (CF). We aimed to explore their relationship across a broad range of CF disease severity and patient age, as well as assess the effect of inhaled lung volume on ventilation distribution.

32 children and adults with CF underwent MBW and 3He-MRI at a lung volume of end-inspiratory tidal volume (EIVT). In addition, 28 patients performed 3He-MRI at total lung capacity. 3He-MRI scans were quantitatively analysed for ventilation defect percentage (VDP), ventilation heterogeneity index (VHI) and the number and size of individual contiguous ventilation defects. From MBW, the lung clearance index, convection-dependent ventilation heterogeneity (Scond) and convection–diffusion-dependent ventilation heterogeneity (Sacin) were calculated.

VDP and VHI at EIVT strongly correlated with lung clearance index (r=0.89 and r=0.88, respectively), Sacin (r=0.84 and r=0.82, respectively) and forced expiratory volume in 1 s (FEV1) (r=−0.79 and r=−0.78, respectively). Two distinct 3He-MRI patterns were highlighted: patients with abnormal FEV1 had significantly (p<0.001) larger, but fewer, contiguous defects than those with normal FEV1, who tended to have numerous small volume defects. These two MRI patterns were delineated by a VDP of ∼10%. At total lung capacity, when compared to EIVT, VDP and VHI reduced in all subjects (p<0.001), demonstrating improved ventilation distribution and regions of volume-reversible and nonreversible ventilation abnormalities.

Recovery of baseline lung function after pulmonary exacerbation in children with primary ciliary dyskinesia

RATIONALE

Spirometry in children with cystic fibrosis (CF) frequently fails to return to baseline after treatment for a pulmonary exacerbation. It is unclear whether the same is true for children with primary ciliary dyskinesia (PCD).

OBJECTIVES

To determine in children with PCD treated with intravenous antibiotics for a pulmonary exacerbation: (1) the proportion who recover to baseline forced expiratory volume at 1 sec (FEV₁ ) within 3 months after treatment and (2) to try to identify factors which are associated with failure to regain pre-exacerbation FEV₁ .

METHODS

Cohort study using the PCD database for children at the Royal Brompton Hospital, 2003-2013. We selected the first pulmonary exacerbation treated with intravenous antibiotics. The best FEV₁ within 3 months after treatment was compared to the best FEV₁ in the 12 months before treatment (baseline). Recovery to baseline was defined as any FEV₁ after treatment that was greater than or equal to 90% of the baseline FEV₁ .

RESULTS

32/150 children (21%) had at least one pulmonary exacerbation. 23/30 (77%) regained baseline spirometry within 3 months of treatment. There was no difference between responders and non-responders in any baseline characteristics.

CONCLUSIONS

Around 25% of children with PCD fail to recover to baseline lung function within 3 months following treatment for a pulmonary exacerbation, similar to CF. Better treatment strategies are needed, and the results also suggest that prevention of exacerbations would be a useful end-point in clinical trials. Pediatr Pulmonol. 2016;51:1362-1366. © 2016 Wiley Periodicals, Inc.

Changes in Pulmonary Function and Controlled Ventilation-High Resolution CT of Chest After Antibiotic Therapy in Infants and Young Children with Cystic Fibrosis

BACKGROUND

Infants with cystic fibrosis (CF) develop early progressive lung disease which may be asymptomatic. Infant pulmonary function tests (IPFT) and controlled ventilation-high resolution computed tomography (CV-HRCT) of chest can detect early asymptomatic lung disease. It is not well established that these objective measures can detect changes in lung disease after clinical interventions.

OBJECTIVE

The purpose of this study was to evaluate usefulness of IPFT and CV-HRCT to detect changes in lung disease after intravenous (IV) antibiotic therapy in infants with early CF-related lung disease.

STUDY DESIGN

IPFTs and CV-HRCT done before and after 2 weeks of IV antibiotics in infants at our institution over the last 12 years were compared. CV-HRCTs were compared using the modified Brody scoring system.

RESULTS

The sample included 21 infants, mean age 85.2 ± 47.6 weeks. Mean change in weight was 0.4 ± 0.38 kg (p = 0.001). Significant changes in IPFT included mean % predicted FEV(0.5) (+13.5 %, p = 0.043), mean %FEF(25-75) (+30.2 %, p = 0.008), mean %RV/TLC (-11.2 %, p = 0.008), and mean %FRC/TLC (-4.5 %, p = 0.001). Total Brody scores improved from a median of 10 to 5 (p < 0.001) as did mean scores for airway wall thickening (p = 0.050), air trapping (p < 0.001), and parenchymal opacities (p = 0.003).

CONCLUSION

IPFT and CV-HRCT can be used as objective measures of improvement in lung disease for infants with CF treated with antibiotics.

Small airway deposition of dornase alfa during exacerbations in cystic fibrosis; a randomized controlled clinical trial

INTRODUCTION

Small airway obstruction is important in the pathophysiology of cystic fibrosis (CF) lung disease. Additionally, many CF patients lose lung function in the long term as a result of respiratory tract exacerbations (RTEs). No trials have been performed to optimize mucolytic therapy during a RTE. We investigated whether specifically targeting dornase alfa to the small airways improves small airway obstruction during RTEs.

METHODS

In a multi-center, double-blind, randomized controlled trial CF patients hospitalized for a RTE and on maintenance treatment with dornase alfa were switched to a smart nebulizer. Patients were randomized to small airway deposition (n = 19) or large airway deposition (n = 19) of dornase alfa for at least 7 days. Primary endpoint was forced expiratory flow at 75% of forced vital capacity (FEF75 ).

MAIN RESULTS

Spirometry parameters improved significantly during admission, but the difference in mean change in FEF75 between treatment groups was not significant: 0.7 SD, P = 0.30. FEF25-75 , FEV1 , nocturnal oxygen saturation and diary symptom scores also did not differ between groups.

CONCLUSIONS

This study did not detect a difference if inhaled dornase alfa was targeted to small versus large airways during a RTE. However, the 95% confidence interval for the change in FEF75 was wide. Further studies are needed to improve the effectiveness of RTE treatment in CF.

Failure to recover to baseline pulmonary function after cystic fibrosis pulmonary exacerbation

RATIONALE

Patients with cystic fibrosis periodically experience pulmonary exacerbations. Previous studies have noted that some patients' lung function (FEV(1)) does not improve with treatment.

OBJECTIVES

To determine the proportion of patients treated for a pulmonary exacerbation that does not recover to spirometric baseline, and to identify factors associated with the failure to recover to spirometric baseline.

METHODS

Cohort study using the Cystic Fibrosis Foundation Patient Registry from 2003-2006. We randomly selected one pulmonary exacerbation treated with intravenous antibiotics per patient and compared the best FEV(1) in the 3 months after treatment with the best FEV(1) in the 6 months before treatment. Recovery to baseline was defined as any FEV(1) in the 3 months after treatment that was greater than or equal to 90% of the baseline FEV(1). Multivariable logistic regression was used to estimate associations with the failure to recover to baseline FEV(1).

MEASUREMENTS AND MAIN RESULTS

Of 8,479 pulmonary exacerbations, 25% failed to recover to baseline FEV(1). A higher risk of failing to recover to baseline was associated with female sex; pancreatic insufficiency; being undernourished; Medicaid insurance; persistent infection with Pseudomonas aeruginosa, Burkholderia cepacia complex, or methicillin-resistant Staphylococcus aureus; allergic bronchopulmonary aspergillosis; a longer time since baseline spirometric assessment; and a larger drop in FEV(1) from baseline to treatment initiation.

CONCLUSIONS

For a randomly selected pulmonary exacerbation, 25% of patients' pulmonary function did not recover to baseline after treatment with intravenous antibiotics. We identified factors associated with the failure to recover to baseline, allowing clinicians to identify patients who may benefit from closer monitoring and more aggressive treatment.

Return of FEV1 after pulmonary exacerbation in children with cystic fibrosis

RATIONALE

Lung function (FEV(1)) generally improves during treatment of pulmonary exacerbations in patients with cystic fibrosis (CF). However, it is unclear how often return to previous baseline FEV(1) is achieved.

OBJECTIVES

(1) To determine the proportion of pediatric patients with CF treated for a pulmonary exacerbation who fail to recover to baseline FEV(1) and (2) to identify factors associated with this failure.

METHODS

We performed a case-control analysis of patients from a single pediatric CF center admitted for their first pulmonary exacerbation in 2001-2006. Patients were considered to have recovered to baseline FEV(1) if their best FEV(1) within the 3 months following treatment was >or=95% of the best FEV(1) during the 6 months prior to treatment. Logistic regression was used to estimate associations between clinical characteristics and failure to regain baseline FEV(1).

RESULTS

Of 104 patients, 24 (23.1%) did not recover to baseline FEV(1). The adjusted odds ratio of failure to recover to baseline FEV(1) was 1.49 (95% confidence interval [CI] 1.20, 1.86) for every 5% greater decline in FEV(1) from baseline to admission. In exploratory analyses, the adjusted odds ratios for the failure to recover to baseline were also significantly higher for patients who were evaluated in our CF clinic more frequently between the baseline measurement and admission, were younger, or were insured by Medicaid.

CONCLUSIONS

Approximately one in four patients with CF failed to recover to baseline lung function after a pulmonary exacerbation despite treatment with intravenous antibiotics. Failure to recover to baseline was associated with the degree of decline in FEV(1) that had occurred prior to hospital admission, suggesting opportunities for earlier intervention to improve lung function outcomes. Additional studies are needed to determine how the failure to recover to baseline affects subsequent FEV(1) decline.

Using index of ventilation to assess response to treatment for acute pulmonary exacerbation in children with cystic fibrosis

BACKGROUND

The use of alternative more sensitive measures has become a focus of research in CF. The utility of indexes of ventilation, Lung Clearance Index (LCI) and peak aerobic capacity (peak VO(2)), were studied as assessment tools in gauging response to intravenous (IV) therapy in acute pulmonary exacerbation, in comparison to the more commonly used index of forced expiratory volume in 1 sec (FEV(1)). The utility of a previously published clinical score was further explored.

METHODS

Patients aged 8-18 years admitted for IV antibiotic treatment of a pulmonary exacerbation were recruited. Spirometry, plethysmography, multiple breath nitrogen washout, exercise testing, and Cystic Fibrosis Clinical Score (CFCS) were performed on admission and prior to discharge.

RESULTS

Twenty-eight patients were recruited, with a mean (range) age of 13.7 (8; 17) years, 16 female and 12 male. Mean (range) admission FEV(1) was 61.4 (28; 92)% predicted, or z-score -3.09 (-6.15; -0.52), FVC 83.0 (38; 120)% predicted, or z-score -1.71 (-5.66; -1.17), and Shwachman-Kulczycki 68.9 (50; 90). FEV(1) increased by 7.0% (P < 0.01) from admission to discharge. Mean (range) admission LCI, 10.10 (6.87; 14.83), decreased by 3.8% (P = 0.03). Mean (range) admission peak VO(2) (ml/kg/min), 31.2 (23.4; 45.4), increased on discharge by 6.6% (P < 0.01). Proposed clinical thresholds, based on the available variability data, highlighted the heterogeneity of response in lung function tests. Mean (range) admission CFCS, 26.5 (19; 39), decreased to 19.9 (13; 31) on discharge, a 25.2% improvement (P < 0.01). CFCS demonstrated improvement in 27 of 28 patients. Changes in peak VO(2) (r = -0.50, P = 0.02) and LCI (r = 0.48, P = 0.01) correlated with CFCS change.

CONCLUSIONS

In children with mild-to-moderate CF, whilst statistically significant improvement in both LCI and peak VO(2) were seen, heterogeneity of response was evident. The most consistent improvement was seen in CFCS. Correlation of LCI and peak VO(2) with change in clinical score (CFCS) was seen. The full clinical significance of these changes in LCI and peak VO(2) needs to be evaluated further with additional variability data. The CFCS may be useful in the assessment of response to treatment in CF but requires formal validation.

High-resolution computed tomography (HRCT) should not be considered as a routine assessment method in cystic fibrosis lung disease

High-resolution computed tomography (HRCT) scanning of the chest should not be considered a routine clinical investigation in the management of CF. Although it demonstrates the detection of early lung damage in children with cystic fibrosis (CF), before HRCT can be considered for routine clinical use in CF it needs to be shown that the benefit from the information obtained will out-weigh potential risks. There is insufficient evidence for the benefit of HRCT for its inclusion into routine care. Moreover, in the absence of information resulting in change in management, HRCT has the potential to increase anxiety for both clinicians and families. In order to advocate for incorporating this technology into routine CF care, further support for its role in management decisions is needed.

Gas mixing efficiency from birth to adulthood measured by multiple-breath washout

Efficient mixing of inspired gas with the resident gas of the lung is an essential requirement of effective respiration. This review focuses on one method for quantifying ventilation inhomogeneity: the multiple-breath inert gas washout (MBW). MBW has been employed as a research tool in adults and school age children for more than 50 years. Modifications allowing data collection in infants and preschoolers have been described recently. Indices of overall ventilation inhomogeneity, such as the lung clearance index and moment ratios, are raised in many infants with lung disease of prematurity, and in young children with cystic fibrosis. These indices may be more sensitive than other lung function measures for the early detection of airway disease. We describe, for the first time, a development of the MBW analysis that allows calculation of acinar and conductive zone inhomogeneity indices in spontaneously breathing children. Although methodological and analytical issues remain, the future clinical and research applications of MBW justify accelerated research in this field.

Comparative analysis of Cystic Fibrosis Registry data from the UK with USA, France and Australasia

BACKGROUND

Using the UK Cystic Fibrosis Database, we analysed the health of the UK CF paediatric population (UKPP) in terms of their biographical, clinical and infection status and compared outcomes with the US, French and Australasian CF Registries.

METHODS

UKPP data were collected for 2,673 patients aged less than 18 years in 2001 and used as a reference base for comparison with the most recent equivalent CF Registry reports.

RESULTS

Although differences exist between National CF Registries, all record similar demographic factors and key outcomes. Where plausible comparisons can be made, we report that the UKPP had the oldest median age (15.0 years), the Australasian population had the lowest median age at diagnosis (1.8 months). Approximately, double the expected number of UKPP patients (23% and 19%, respectively) fall below the 10th centile for height and weight with similar outcomes in Australasia. UKPP and French populations had similar proportions with FEV1 >80% predicted (53% and 54%, respectively).

CONCLUSION

Each Registry's data systems have developed independently providing a first step towards international comparisons. Standardisation of data collection criteria and definition for national CF Registries is required and we propose a standardised minimum data set, which would facilitate data integration as part of a global Registry for CF.

Multiple-breath washout as a marker of lung disease in preschool children with cystic fibrosis

Sensitive measures of lung function applicable to young subjects are needed to detect early cystic fibrosis (CF) lung disease. Forty children with CF aged 2 to 5 years and 37 age-matched healthy control subjects performed multiple-breath inert gas washout, plethysmography, and spirometry. Thirty children in each group successfully completed all measures, with success on first visit being between 68 and 86% for all three measures. Children with CF had significantly higher lung clearance index (mean [95% CI] difference for CF control 2.7 [1.9, 3.6], p < 0.001) and specific airway resistance (1.65 z-scores [0.96, 2.33], p < 0.001), and significantly lower forced expired volume in 0.5 seconds (-0.49 z-scores [-0.95, -0.03], p < 0.05). Abnormal lung function results were identified in 22 (73%) of 30 children with CF by multiple-breath washout, compared with 14 (47%) of 30 by plethysmography, and 4 (13%) of 30 by spirometry. Children with CF who were infected with Pseudomonas aeruginosa had significantly higher lung clearance index, but no significant difference in other lung function measures, when compared with noninfected children. Most preschool children can perform multiple-breath washout, plethysmography, and spirometry at first attempt. Multiple-breath washout detects abnormal lung function in children with CF more readily than plethysmography or spirometry.

Correlation between digital clubbing and pulmonary function in cystic fibrosis

The correlation between digital clubbing and certain pulmonary function derangements (hypoxemia and FEV(1)) was previously described. However, the relationship between digital clubbing and other measures of pulmonary function or the presence of liver disease in patients with cystic fibrosis (CF) is poorly defined. Hence we compared the digital clubbing index (CI: ratio of distal phalangeal depth to interphalangeal depth) of 100 patients with CF (43 males, 57 females; mean age, 15.7 +/- 7.3 years) with that of 100 age- and gender-matched healthy controls. Digital clubbing was defined as a CI > or = 1.00 (mean + 2.6 SD; 99% of normal subjects). The CI and its relationship to pulmonary function and to liver disease was then evaluated in the CF patients. Digital clubbing was present in 75/100 (75%) of CF patients but was absent in all controls (P < 0.0001). In CF patients, CI was inversely correlated with PaO(2) (r = -0.555; P < 0.001), FEV(1) (r = -0.499; P < 0.001), and FEF(25-75%) (r = -0.404; P < 0.001), and was positively correlated with RV (r = 0.285; P < 0.05) and the slope of phase 3 of single-breath nitrogen washout (SP3N(2)) (r = 0.532; P < 0.01). There was no significant correlation between CI and age (r = 0.020; P = 0.84), TLC (r = -0.097; P = 0.34), PaCO(2) (r = 0.167; P = 0.10), or history of liver disease (P = 0.08). We conclude that in CF, the degree of digital clubbing is related to degree of hypoxemia, airways obstruction, hyperinflation, and nonuniformity of ventilation.

Defining a pulmonary exacerbation in cystic fibrosis

OBJECTIVES

Despite the central importance of pulmonary exacerbations (PExs) as an outcome measure in cystic fibrosis clinical trials, no standardized definition of PEx exists. We conducted a prospective, multicenter study to establish a standardized PEx definition and score for use in clinical trials, based on clinical status rather than on treatment decisions.

STUDY DESIGN

Subjects were 246 patients enrolled in the placebo arm of a randomized, controlled trial of tobramycin for inhalation. Physician-investigators completed PEx questionnaires on all subjects at scheduled intervals during the 6-month study, indicating new or worsening symptoms, physical examination findings, and impression of PEx status (presence or absence and severity). Logistic regression was used to assess the relative importance of each of the characteristics in predicting a PEx.

RESULTS

We developed 2 PEx scores that use easily ascertained symptoms and chest examination findings; one also includes change in forced expiratory volume in 1 second over the preceding month. Both scores were sensitive and specific for predicting the presence of a PEx (sensitivity, 86%; specificity, 86%). The scores were validated in subjects in the intervention arm of the trial.

CONCLUSION

We hope that the proposed PEx score might serve as a standardized outcome measure for future clinical trials in cystic fibrosis, allowing meaningful comparisons of study results.

Spirometer-triggered high-resolution computed tomography and pulmonary function measurements during an acute exacerbation in patients with cystic fibrosis

OBJECTIVE

To evaluate a high-resolution computed tomography (HRCT) scoring system, clinical parameters, and pulmonary function measurements in patients with cystic fibrosis (CF) before and after therapy for a pulmonary exacerbation.

STUDY DESIGN

Patients (n = 17) were evaluated by spirometer-triggered HRCT imaging, clinical parameters, and pulmonary function tests (PFTs) before and after treatment. HRCT scans were reviewed by 3 radiologists using a modified Bhalla scoring system.

RESULTS

Bronchiectasis, bronchial wall thickening, and air trapping were identified in all subjects on initial evaluation. The initial total HRCT score correlated significantly with the Brasfield score (r = -.91, P <.001) and several PFT measures. After treatment, there were improvements in the acute change clinical score (ACCS) (P <.001), most pulmonary function measurements, and total HRCT score (P <.05). Bronchiectasis, bronchial wall thickening, and air trapping did not significantly change. Mucus plugging subcomponent HRCT score, slow vital capacity (SVC), forced expiratory volume in 1 second (FEV(1)), and forced vital capacity (FVC) (percent predicted) and reversible and total HRCT scores were most sensitive to change by effect size analysis.

CONCLUSIONS

Improvements occurred with treatment in total and reversible HRCT scores, PFTs, and ACCS. Total and reversible HRCT scores and percent predicted SVC, FEV1, and FVC were the most sensitive to change. The greatest change was seen in the mucus plugging subcomponent HRCT score.

Overall and peripheral inhomogeneity of ventilation in patients with stable cystic fibrosis

We studied distribution of ventilation in patients with cystic fibrosis (CF) who had not had an exacerbation for some time. Patients performed either the vital capacity nitrogen (N(2)) single-breath washout test (VC test) or a modified single-breath washout consisting of 1 L inspired from functional residual capacity (FRC test) of 90% oxygen (O(2)), 5% helium (He), and 5% sulfur hexafluoride (SF(6)). We computed the slopes of phase III of N(2) concentration from the VC test (S(N2) (VC)) and the phase III slopes of the He (S(He)): The SF(6) (S(SF6)), and curves from the FRC test. S(N2) (VC) may be regarded as an index of overall ventilation and the difference (S(SF6) - S(He)) as an index of peripheral ventilation. Three groups were studied: CF, 28 CF patients (8-36 years of age); normal controls (NC), 33 normal nonsmokers (9-55 years of age); and a smoking group (SG), 42 non-CF smoking patients (39-79 years of age). Compared to the NC group, S(N2) (VC) is increased in the CF group, reflecting an overall ventilation impairment. There is no difference in S(N2) (VC) between the CF group and the SG group, suggesting that S(N2), though sensitive, is nonspecific. Compared to both NC and SG groups, (S(SF6) - S(He)) is decreased in the CF group, being on the average negative. This may imply that there is a peripheral impairment in the distribution of ventilation that originates in terminal and respiratory bronchioles. Negative (S(SF6) - S(He)) is statistically associated with the youngest CF patients, suggesting that terminal and respiratory bronchiolar involvement is linked to early stages of the disease. In older CF patients, (S(SF6) - S(He)) is more often positive, suggesting that even more distal airways, such as alveolar ducts, become involved in peripheral inhomogeneity of ventilation.

An audit of the effect of intravenous antibiotic treatment on spirometric measures of pulmonary function in cystic fibrosis

BACKGROUND

This retrospective audit was undertaken to compare the efficacy of home intravenous (i.v.) antibiotic therapy, hospital i.v. antibiotic therapy and a combination of these 2 approaches, as determined by spirometric measures of lung function in cystic fibrosis (CF) patients, each with an acute respiratory exacerbation.

METHODS

Pulmonary function, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow rate between 25 per cent and 75 per cent of vital capacity (FEF25-75), and peak expiratory flow rate (PEFR) were compared between groups at the beginning and at the end of an IV antibiotic course.

RESULTS

Treatment of exacerbations resulted in a significant improvement (p < 0.05) in lung function irrespective of where patients were treated. The percentage improvement in FEV1, FVC, and FEF25-75, were significantly greater in patients treated in hospital compared to those who had home i.v. treatment (p < 0.05).

CONCLUSION

Hospital i.v. antibiotic therapy resulted in greater improvements in FEV1, FVC and FEF25-75 than home i.v. antibiotic therapy in CF patients with an acute respiratory infection.

Pulmonary function in hospitalized infants and toddlers with cystic fibrosis

In older children with cystic fibrosis (CF), well-documented improvements in lung function occur during hospitalization for treatment of pulmonary exacerbations.

OBJECTIVES

(1) To test the hypothesis that improvement in lung function occurs in infants and toddlers hospitalized because of CF pulmonary exacerbations. (2) To compare changes in lung function measured during forced expiratory flow and tidal breathing.

STUDY DESIGN

Seventeen infants and toddlers with CF were evaluated at the beginning and end of hospitalization by the rapid thoracic compression technique to yield maximal flow at forced residual capacity. Tidal mechanics were measured by the esophageal balloon technique to yield lung conductance and compliance.

RESULTS

Lung function improved during the course of hospitalization. The greatest change was observed in measurements of maximal flow at functional residual capacity (.VmaxFRC), increasing from 38.5% +/- 6% predicted (mean +/- SEM) to 59.8% +/- 6% at the end (p < 0.005). Lung conductance (GL) increased from 60% +/- 6% to 78% +/- 8% (p < 0.02); lung compliance (CL) increased from 66% +/- 5% to 75% +/- 5% (p < 0.03). The degree of improvement of .VmaxFRC, GL, and CL was related to baseline measurements; those with poorer pulmonary function at baseline had the greatest degree of improvement during hospitalization.

CONCLUSION

Assessments of airflow obstruction from measurements of .VmaxFRC and GL do not necessarily demonstrate similar findings in a given infant with CF, perhaps because these two techniques measure different physiologic properties. Changes in .VmaxFRC may best reflect the predominant pathophysiology of lung disease in infants and toddlers with CF.

No paradoxical bronchodilator response with forced oscillation technique in children with cystic fibrosis

STUDY OBJECTIVES

The aim of the present study was to evaluate the forced oscillation technique (FOT) in cystic fibrosis (CF) children and to participate in the discussion about the usefulness of beta2-antagonists in CF.

DESIGN

Pulmonary function was measured with spirometry, body plethysmography, and FOT before and after inhalation of 200 microg of albuterol (salbutamol). The following were collected: vital capacity (VC), FEV1, FEV1/VC, airway resistance (Raw), thoracic gas volume, respiratory system resistance (Rrs) and respiratory system reactance (Xrs) at 6 Hz (Rrs6 and Xrs6), and resonance frequency.

SETTING

The study was set up at a university hospital with a CF population of 125 children and adolescents.

PATIENTS

Data were collected on 20 patients in stable condition able to perform the three lung function tests.

MEASUREMENTS AND RESULTS

Mean baseline values (+/-SD) were 0.36+/-0.15 kPa/L/s for Raw, 0.5+/-0.15 kPa/L/s for Rrs6, and 61+/-22% predicted for FEV1. The relationship between FEV1 and Raw or Rrs6 was poor. Xrs6 and FEV1/VC correlated weakly (r=0.56; p < 0.05). After bronchodilator administration, the mean changes +/-SD in percent of baseline were +3 +/- 11% for FEV1, -16 +/- 22% for Raw, and -16 +/- 9% for Rrs6. In six patients, a paradoxical decrease in FEV1 was measured but an increase in Rrs6 was never found; in two patients, an increase of Raw of < 10% was found. In 13 patients, the decrease of Rrs6 was > 12%.

CONCLUSIONS

The results suggest that FOT measurements cannot replace baseline spirometric measurements in CF, but that the evaluation of the effect of beta2-agonists on the airway diameter in CF should include an FOT measurement.

Lung function from infancy to school age in cystic fibrosis

The aim was to investigate pulmonary mechanics in patients with cystic fibrosis during infancy and again in early childhood to see whether infant tests predicted status at school age. Plethysmographic measurements of thoracic gas volume and airways resistance were made in 29 patients at 6 months and again at 5 years 10 months. Maximum flow at functional residual capacity was measured during infancy for comparison with maximum expiratory flow rates during childhood. While many patients had normal measurements during infancy, pulmonary function had deteriorated by school age. Thoracic gas volume at school age was significantly related to the values in infancy, but other measurements made during childhood were independent of infant values. The relations between measurements in infancy and early childhood described here provide a background against which the role of external factors on pulmonary function in young children with cystic fibrosis can be investigated.