The role of cardiopulmonary exercise testing in evaluating children with exercise induced dyspnoea.

Exercise induced dyspnoea (EID) is a common manifestation in children and adolescents. Although EID is commonly attributed to exercise induced bronchoconstriction, several conditions other than asthma can cause EID in otherwise healthy children and adolescents. Cardiopulmonary exercise testing (CPET) offers a non-invasive comprehensive assessment of the cardiovascular, ventilatory and metabolic responses to exercise and is a powerful diagnostic and prognostic tool. CPET is a reproducible, non-invasive form of testing that allows for comparison against age- and gender-specific norms. CPET can assess the child's exercise capacity, determine the limiting factors associated with this, and be used to prescribe individualised interventions. EID can occur due to asthma, exercise induced laryngeal obstruction, breathing pattern disorders, chest wall restriction and cardiovascular pathology among other causes. Differentiating between these varied causes is important if effective therapy is to be initiated and quality of life improved in subjects with EID.

Interpretation of pediatric lung function: impact of ethnicity.

RATIONALE: To evaluate the appropriateness of spirometric and plethysmographic reference equations in healthy young children according to ethnic origin. METHODS: Spirometry data were collated in 400 healthy children (214 Black and 186 White) aged 6-12 years. Of these children, 68 Black and 115 White children also undertook plethysmography. Results were expressed as percent predicted according to commonly used equations for spirometry and plethysmography. RESULTS: Black children had lower lung function for a given height compared to White children. The magnitude and direction of these differences varied according to specific outcome. In the studied age range (6-12 years) the ethnic-specific Wang equations were adequate for spirometry (mean results approximating 100% predicted in both ethnic groups). By contrast, significant differences were found between observed and % predicted plethysmographic lung volumes according to published equations derived from White children: Among the Black children, function residual capacity (FRC) and total lung capacity (TLC) were on average, 14 and 6% lower than predicted, whereas mean residual volume (RV) and RV/TLC were 4 and 10% higher. Among White children, the Rosenthal equations gave the best fit, with the exception of FRC which was, on average, 9% lower than predicted. CONCLUSION: Spirometry equations may suffice in Black children; however, interpretation of static lung volumes in Black children is limited due to inappropriate reference equations. More appropriate plethysmographic reference equations that are applicable to all ethnic groups across the entire age range are urgently needed.

Alveolar LCI vs. standard LCI in detecting early CF lung disease.

Multiple breath washout (MBW) is a sensitive technique that detects early airways disease. However in very young children, large equipment and physiological dead space relative to lung volumes may result in a higher Lung Clearance Index (LCI). We investigated whether alveolar LCI (aLCI) is a more sensitive index than standard LCI in children. MBW data-sets from children aged 0.1-10.7 years [97 healthy controls and 93 with cystic fibrosis (CF)] were analysed. LCI is traditionally calculated by dividing the cumulative expired volume (CEV) by functional residual capacity (FRC) after correcting for equipment dead space. aLCI was calculated similarly, but after correcting the CEV and FRC for Langley's physiological dead space. There was a significant correlation between LCI and aLCI in health (r(2): 0.993; p<0.0001) and disease (r(2): 0.984; p<0.0001). Sensitivity of both LCI and aLCI in detecting abnormal lung function in CF was 39% during infancy, which increased to 77% and 83% respectively in older children. However, the difference in sensitivity (aLCI vs. LCI) was not significant (p=0.36). We conclude that LCI is minimally affected by airway deadspace, or relative equipment deadspace, and is an appropriate measure of lung function in infancy.

Relationship between past airway pathology and current lung function in preschool wheezers.

The functional outcome in preschool severe wheezers with eosinophilic airway inflammation and increased reticular basement membrane (RBM) thickness is unknown. We investigated the relationship between airway pathology at age 2 yrs and lung function at age 4-6 yrs in previous severe wheezers. Severe wheezers previously investigated by endobronchial biopsy and healthy children aged 4-6 yrs were recruited. Lung clearance index (LCI), conducting zone ventilation inhomogeneity (S(cond)), acinar ventilation inhomogeneity by multiple-breath washout, plethysmographic-specific airway resistance and exhaled nitric oxide fraction (F(eNO)) were measured. Lung function was compared between wheezers and healthy controls, and in wheezers correlated with past RBM thickness and mucosal eosinophilia (EG2+ cells). 72 healthy controls and 28 previous severe wheezers were tested. Wheezers had significantly higher median LCI (6.8 versus 6.6; p=0.001) and S(cond) (0.046 versus 0.016; p<0.0005) than healthy controls. Past RBM thickness (r=0.474, p=0.047) and EG2+ cells (r=0.552, p=0.041) showed significant correlations with current F(eNO), but no correlations were seen between past RBM thickness and current lung function. RBM thickness and EG2+ cells at age 2 yrs show a significant positive association with F(eNO) at age 5 yrs. Although lung function was abnormal at age 5 yrs in severe wheezers, this did not correlate with past RBM thickness.

The Young Everest Study: effects of hypoxia at high altitude on cardiorespiratory function and general well-being in healthy children.

OBJECTIVES: To assess the effect of altitude and acclimatisation on cardiorespiratory function and well-being in healthy children. METHODS: A daily symptom diary, serial measurements of spirometry, end-tidal carbon dioxide (etCO(2)) and daytime and overnight pulse oximetry (SpO(2)), were undertaken at sea level and altitudes up to 3500 m in healthy children during a trekking holiday. SpO(2) at altitude was compared with that in flight and during acute hypoxic challenge (breathing 15% oxygen) at sea level. RESULTS: Measurements were obtained in nine children aged 6-13 years (median 8). SpO(2) decreased significantly during the hypoxic challenge (difference -5%, 95% CI -6 to -3%, p<0.01) but remained above 90% in all children. There was a significant fall in daytime and overnight SpO(2) (95% CI -11.9 to -7.5% and -12 to -8, respectively) and etCO(2) (-8.5 to -4.5 mm Hg) as the children ascended to 3500 m. There was a significant increase in SpO(2) (95% CI 1.1 to 4.9%) and a further drop in etCO(2) (-5.9 to -0.8 mm Hg) after a week at altitude, etCO(2) being negatively correlated with SpO(2). There was no correlation between SpO(2) during hypoxic challenge, in flight or at altitude. Lung function remained within 7% of baseline in all but two children, in whom reductions of up to 23% in FVC and 16% FEV(1) were observed at altitude. The children generally remained well, but the Lake Louise scoring system was unreliable in this age group. CONCLUSIONS: A wide range of physiological responses to altitude are evident in healthy children. This study should inform future larger studies in children to improve understanding of responses to hypoxia in health and disease.

Non-cystic fibrosis bronchiectasis in childhood: longitudinal growth and lung function.

BACKGROUND: Non-cystic fibrosis (non-CF) bronchiectasis often starts in childhood with a significant impact on adult morbidity. Little is known about disease progression through childhood and the effect on growth and spirometry. This study reviews longitudinal lung function and growth in children with non-CF bronchiectasis. METHODS: The case notes of patients with non-CF bronchiectasis were reviewed retrospectively. Patients were included if at least three calendar years of lung function data were available. Anthropometric measurements and annual spirometry were analysed over both two and four consecutive years. Changes over time were assessed using Generalised Estimating Equations. RESULTS: Fifty-nine patients (31 boys) were identified. At baseline the median age was 8.2 years (range 4.8-15.8), the mean (SD) for height, weight and body mass index (BMI) for age z-scores were -0.68 (1.31), -0.19 (1.34) and 0.19 (1.38), respectively. At baseline, the mean (SD) z-score for forced expiratory volume in 1 s (FEV(1)) was -2.61 (1.82). Over 2 years (n = 59), mean FEV(1) and forced vital capacity (FVC) improved by 0.17 (95% CI 0.01 to 0.34, p = 0.039) and 0.21 (95% CI 0.04 to 0.39, p = 0.016) z-scores per annum, respectively. Over 4 years there was improvement in height-for-age z-scores (slope 0.05, 95% CI 0.01 to 0.095, p = 0.01) but no improvement in other anthropometric variables. There was no change in spirometry (FEV(1) slope 0.00, 95% CI -0.09 to 0.09, p = 0.999 and FVC slope 0.09, 95% CI -0.09 to 0.1, p = 0.859). CONCLUSIONS: Children with non-CF bronchiectasis show adequate growth over time. Lung function stabilises but does not normalise with treatment, underscoring the need for early detection and institution of appropriate therapy.

Role of routine computed tomography in paediatric pleural empyema.

BACKGROUND: The incidence of empyema in children is increasing worldwide. While there are emerging data for the best treatment options, there is little evidence to support the imaging modalities used to guide treatment, particularly with regard to the role of routine CT scanning. The aims of this study were to develop a radiological scoring system for paediatric empyema and to assess the utility of routine CT scanning in this disease. METHODS: Children with empyema were prospectively enrolled over a 3-year period into a randomised clinical trial of video-assisted thoracoscopic surgery versus percutaneous chest drain insertion and urokinase. All children received a preoperative chest radiograph (CXR), pleural ultrasound scan (USS) and chest CT scan. In the urokinase arm the clinician inserted the drain with USS evidence only and did not have access to the CT scan at the time of insertion to reflect clinical practice. A scoring system was developed for each individual radiological modality and used to compare imaging characteristics of the pleural fluid collection and underlying parenchyma and to assess the utility of USS and CT to predict length of stay after the intervention. RESULTS: Of the 60 subjects recruited, 46 had USS images available for review, 36 had a CT scan which met the inclusion criteria and 31 had all three radiological measurements (CT, USS and CXR) available for analysis. There was substantial interobserver agreement for USS grades (kappa = 0.709) and moderate agreement for total CT scores (kappa = 0.520). There were weak correlations between USS grade and total CT score as well as CT loculation and density scores. Of the 25 CXRs showing simple opacification of the underlying parenchyma only, CT demonstrated simple consolidation (n = 14), necrotising pneumonia (n = 7), cavitary necrosis (n = 3) and pneumatoceles (n = 1). No abnormality was detected on CT scanning which directly altered clinical management. Neither the USS score nor the CT score, nor a combination of the two, were able to predict length of hospital stay. CONCLUSIONS: CT scanning detects more parenchymal abnormalities than chest radiography. However, the additional information does not alter management and is unable to predict clinical outcome. This suggests that there is no role for the routine use of CT scanning in children if treated with urokinase and percutaneous chest drain. The omission of routine CT scanning in empyema will reduce the exposure of children to unnecessary radiation and reduce costs. TRIAL REGISTRATION NUMBER: The trial is fully registered with clinicaltrials.gov (ID: NCT00144950).

Atypical invasive aspergillosis in a neutropenic child.

Invasive aspergillosis (IA) is an aggressive disease with a high mortality rate requiring a high index of clinical suspicion in susceptible patients. We report an atypical presentation of IA, not previously published. A 2-year-old girl with underlying neuroblastoma developed IA, which manifested as fungal pneumonia associated with an intrabronchial polypoid mass.

Ventilation induced pneumothorax following resolved empyema.

We report a case of pneumothorax as a result of positive pressure ventilation in a child previously treated for empyema. Three months following discharge for successful treatment of empyema our patient received a general anesthetic for an elective MRI of the brain for investigation of nystagmus. During recovery from the anesthetic he developed respiratory distress and was found to have a loculated pneumothorax. We propose that pleural fragility in childhood empyema possibly persists even after clinical resolution and in this case for up to 3 months. The complication of pneumothorax should be considered in all patients receiving positive pressure ventilation following resolved empyema.

Non-CF bronchiectasis: does knowing the aetiology lead to changes in management?

The aim of the current study was to review the aetiology of non-cystic fibrosis (CF) bronchiectasis from two tertiary paediatric respiratory units in order to determine how often making a specific aetiological diagnosis leads to a change in management, and to assess the contribution of computed tomography (CT) in determining the underlying diagnosis. The case records of all patients who were diagnosed as having bronchiectasis by CT, currently being seen at the Royal Brompton Hospital and Great Ormond Street Hospital for Children (London, UK), were reviewed. All patients had undergone extensive investigations, and the underlying aetiology and the area of pulmonary involvement (as seen on CT) were recorded. A total of 136 patients were identified; there were 65 young males and the group median (range) age was 12.1 yrs (3.1-18.1). Immunodeficiency, aspiration and primary ciliary dyskinesia accounted for 67% of the cases. In 77 (56%) children, the identification of a cause led to a specific change in management. There was no association between aetiology and the distribution of CT abnormalities. In conclusion, immunodeficiency and other intrinsic abnormalities account for the majority of cases of non-cystic fibrosis bronchiectasis seen in the current authors' units. Computed tomography scans do not contribute towards identifying the aetiology and, most importantly, a specific aetiological diagnosis frequently leads to a change in management.