Lung function in childhood. III. Measurement of airflow resistance in healthy children

An official American Thoracic Society workshop report: optimal lung function tests for monitoring cystic fibrosis, bronchopulmonary dysplasia, and recurrent wheezing in children less than 6 years of age

Although pulmonary function testing plays a key role in the diagnosis and management of chronic pulmonary conditions in children under 6 years of age, objective physiologic assessment is limited in the clinical care of infants and children less than 6 years old, due to the challenges of measuring lung function in this age range. Ongoing research in lung function testing in infants, toddlers, and preschoolers has resulted in techniques that show promise as safe, feasible, and potentially clinically useful tests. Official American Thoracic Society workshops were convened in 2009 and 2010 to review six lung function tests based on a comprehensive review of the literature (infant raised-volume rapid thoracic compression and plethysmography, preschool spirometry, specific airway resistance, forced oscillation, the interrupter technique, and multiple-breath washout). In these proceedings, the current state of the art for each of these tests is reviewed as it applies to the clinical management of infants and children under 6 years of age with cystic fibrosis, bronchopulmonary dysplasia, and recurrent wheeze, using a standardized format that allows easy comparison between the measures. Although insufficient evidence exists to recommend incorporation of these tests into the routine diagnostic evaluation and clinical monitoring of infants and young children with cystic fibrosis, bronchopulmonary dysplasia, or recurrent wheeze, they may be valuable tools with which to address specific concerns, such as ongoing symptoms or monitoring response to treatment, and as outcome measures in clinical research studies.

The interrupter technique to assess airway responsiveness in children with cystic fibrosis

The aim of this study was to assess the validity of the interrupter technique (Rint) in measuring airway responsiveness in children with cystic fibrosis. Fifty children (aged 6-16 years) with cystic fibrosis performed six Rint measurements followed by three acceptable forced expiratory maneuvers. Each child then inhaled 5 mg of nebulized salbutamol by facemask. After 20 min the Rint and forced expiratory measurements were repeated. In the population as a whole a moderate but significant correlation between inverse Rint and FEV1 values was observed, both before and after inhaled bronchodilator (r=0.71 and 0.72, respectively, P < 0.001). However, when changes in Rint and FEV1 readings following inhaled bronchodilator were examined, no relationship was seen. Indeed, the two methods identified completely different subsets of children as being bronchodilator responsive. These results indicate that although a relationship exists between Rint and FEV1 in the whole population, this is not the case in individual children. Rint and FEV1 reflect different aspects of lung function. It is not appropriate to use Rint as a simple alternative for FEV1 in children with cystic fibrosis when assessing airway responsiveness.

Level of lung function required to use the Camic Datamaster breath alcohol testing device

In the UK a person who, without reasonable excuse, fails to provide a breath specimen when required to under the 1988 Road Traffic Act, is guilty of an offense. In the past many suspects claim to have experienced difficulty providing breath samples for evidential machines. This paper describes experiments carried out on human subjects, both healthy and suffering a variety of respiratory illness. The experiments were designed to assess the level of respiratory performance required to provide a satisfactory breath sample for the Camic Datamaster. In this study it was found that both actual spirometry values and the percentage of predicted values were both important indicators.

Respiratory function in childhood following repair of oesophageal atresia and tracheoesophageal fistula

AIM

To determine the relation between respiratory function in infancy and at school age in children who have undergone oesophageal atresia and tracheoesophageal fistula repair, and assess the value of infant respiratory function testing; and to examine the effect of bronchodilators.

METHOD

Fourteen children (6 girls, and 8 boys) who had undergone respiratory function testing in infancy were retested at school age (7-12 years). Measurements included lung volume, airways resistance, peak flow, and spirometry. Clinical problems were investigated by questionnaire. Twelve children had repeat measurements after taking salbutamol.

RESULTS

Predominant complaints were non-productive cough and dysphagia, but even those children with major problems in infancy reported few restrictions at school or in sport or social activities. Respiratory function and clinical findings at school age appeared unrelated to status in infancy, such that even the patients with severe tracheomalacia requiring aortopexy did not have lung function testing suggestive of malacia at school age. Most patients showed a restrictive pattern of lung volume which would appear to result from reduced lung growth after surgery rather than being a concomitant feature of the primary congenital abnormality. Although six children reported wheeze and four had a diagnosis of asthma, only one responded to salbutamol. This suggests that a tendency to attribute all lower respiratory symptoms to asthma may have led to an overdiagnosis of this condition in this patient group.

CONCLUSION

Respiratory function testing in infancy is of limited value in medium term prognosis, but may aid management of contemporary clinical signs. In children respiratory function testing is valuable in assessing suspected asthma and effects of bronchodilators.

Home-made spacers for bronchodilator therapy in children with acute asthma: a randomised trial

BACKGROUND

A metered-dose inhaler (MDI) with spacer is the best way to deliver bronchodilator therapy for treatment of acute asthma. In developing countries, commercially produced spacers are generally unavailable or too costly. We tested the efficacy of home-made spacers (500 mL plastic bottle, polystyrene cup) compared with a conventional spacer for delivery of a beta2 agonist via MDI for children with acute asthma.

METHODS

We studied children aged 5 to 13 years with acute asthma, stratified into those with mild airways obstruction (peak expiratory flow [PEF] 60-79% of predicted value) or moderate to severe airways obstruction (PEF 20-59% of predicted value). A beta2 agonist (fenoterol hydrobromide) was given via MDI and one of four randomly assigned spacers (conventional spacer, sealed 500 mL plastic bottle, unsealed 500 mL bottle, 200 mL polystyrene cup). Clinical score, pulmonary function tests, and oximetry were recorded at baseline and 15 min after treatment. If a second bronchodilator treatment was needed, nebulised fenoterol was given and the assessment repeated 15 min later. Primary outcome measures were changes in clinical score and pulmonary function, and need for and response to nebulisation.

FINDINGS

88 children were eligible for study. In 44 children with moderate to severe airways obstruction, a cup gave significantly less bronchodilation (median increase in: forced expiratory volume in 1 s [FEV1] 0%; PEF 12%) compared with the conventional spacer (37%; 59%), sealed bottle (33%; 36%), or unsealed bottle (18%; 21%, p<0.05 for difference between groups). Nebulisation was required by ten of 11 who had used a cup, nine of 11 who had used an unsealed bottle, eight of 11 who had used a sealed bottle, and only four of 11 who had used a conventional spacer. After nebulisation, improvement in FEV1 (15.5%) and PEF (26%) was more marked in children who had used a cup than in those who had used a conventional spacer (5.5% FEV1; 4% PEF), sealed bottle (3%; 0%), or unsealed bottle (7%; 9%). For 44 children with mild airways obstruction, response to bronchodilator was similar for all spacers and need for nebulisation was not associated with use of a particular spacer.

INTERPRETATION

A conventional spacer and sealed 500 mL plastic bottle produced similar bronchodilation, an unsealed bottle gave intermediate improvement in lung function, and a polystyrene cup was least effective as a spacer for children with moderate to severe airways obstruction. Use of bottle spacers should be incorporated into guidelines for asthma management in developing countries.

Respiratory status and allergy nine to 10 years after acute bronchiolitis

In order to evaluate further the relationship between acute bronchiolitis in infancy and subsequent respiratory problems, children prospectively followed up from the time of their admission to hospital were reviewed along with a group of matched controls recruited at the previous five and a half year assessment. Sixty one index children and 47 controls took part. The groups were well matched for age, height, parental smoking, and social class. Although the prevalence of respiratory symptoms had fallen when related to the previous review, there remained an excess of coughing (48 and 17% in index and control children respectively; odds ratio 4.02) and wheezing (34 and 13% in index and control children respectively; odds ratio 3.59). Bronchodilator therapy was used by 33% of index children compared with 3% of controls. Lung function tests revealed no significant differences in the measurements of lung growth-for example, forced vital capacity, functional residual capacity, and total lung capacity-but the index children had significant reductions in measurements of airways obstruction-for example, forced expiratory volume in one second, maximum expiratory flow at 75, 50 and 25% of vital capacity, and airways resistance. Family history and personal skin tests showed no excess of atopy in the index group. This study supports the claim that the excess respiratory symptoms after acute bronchiolitis are not due to familial or personal susceptibility to atopy.

Lung function in white children aged 4 to 19 years: II--Single breath analysis and plethysmography

OBJECTIVE

A study was performed to determine reference ranges for whole body plethysmographic gas volumes and single breath gas transfer in healthy prepubertal and pubertal schoolchildren.

METHODS

The study was performed in 772 white London schoolchildren (455 male) who were clinically examined, assessed auxologically and, in 63% of cases, pubertally staged. Regression equations for the calculation of standard deviation scores were derived.

RESULTS

Male lung function variables showed a discontinuous pattern of increase with standing height. Linear increases until puberty were followed by a sudden pubertal rise and a further increase with height which was more marked than before puberty. Correction for varying thoracic dimensions eliminated these changes. In females a smoother curvilinear relationship was observed with no correction possible for thoracic size.

CONCLUSIONS

Male puberty leads to profound changes in pulmonary function mostly related to thoracic size, an effect not observed in females.

Measurement of respiratory system resistance by forced oscillation in normal children: a comparison with spirometric values

In 377 children, the commercially available Siregnost FD-5 was used to measure respiratory system resistance (Rrs) by forced oscillation at 10 Hz. The children were between 3 and 18 years of age and, by a detailed questionnaire and conventional pulmonary function testing in 335, they were shown to be representative of the normal pediatric population. There was a linear relationship between Rrs and height (Rrs = 13.9-0.064 x ht (cm), r = -0.87). Children less than 6 years of age had no trouble with using the forced oscillation technique. The smoking of tobacco in the house, the presence of carpets in the child's bedroom, or an atopic family history, alone or in combination, had no influence on Rrs or on any spirometric measure. Forced oscillation is useful in children too young to be able to cooperate with conventional pulmonary function testing.

Placebo controlled trial of systemic corticosteroids in acute childhood asthma

In a randomised controlled trial 38 asthmatic children aged 2-11 yr who had not received regular oral or inhaled steroids during the previous year, were treated with a standard regime of nebulised salbutamol and intravenous aminophylline plus either hydrocortisone and oral prednisolone for 5 days, or placebo. The children were observed throughout their hospital stay and for 3 months afterwards. There was a greater fall in heart rates in the steroid treated group on the second day of treatment (mean diff. 16 beats/min) and at discharge (mean diff. 13 beats/min); p less than 0.025. Peak Expiratory Flow Rates recorded in 26 children, 13 in each group, showed more improvement on day 2 in those given steroids (mean diff 16% predicted); p less than 0.05. This difference was not apparent at discharge but 9 children treated with steroids were clinically wheeze-free when they left hospital compared with 3 in the placebo group, p less than 0.05. There were no differences in respiratory rate, pulsus paradoxus and arterial oxygen saturation. Trends in duration of hospital stay and relapse rate during the succeeding 3 months favoured active treatment. These findings support the use of systemic corticosteroids in addition to high dose bronchodilators to treat 'non steroid dependent' children hospitalised with acute severe asthma.

Controlled trial of budesonide given by the nebuhaler in preschool children with asthma

OBJECTIVE

To determine whether the inhaled corticosteroid budesonide, given by a Nebuhaler spacing device, was effective in prophylaxis of asthma in preschool children.

DESIGN

Double blind, placebo controlled, random order crossover trial with two week practice run in period.

SETTING

Outpatient clinic referrals in secondary referral centre.

PATIENTS

39 children aged 2-6 years selected for the following: able to use Nebuhaler; parents able to complete record card; poorly controlled asthma (defined); not already on systemic or inhaled steroids. Eleven withdrew for various reasons not connected with intolerance to budesonide. Age, sex, other atopies, and symptoms during run in period were similar in the 28 children who completed the trial and in the 11 who withdrew.

INTERVENTIONS

Budesonide 200 micrograms or placebo (both one puff) given twice daily during 6-week treatment or control periods, using Nebuhaler after prior training. Three week "washout" at crossover. Compliance monitored by weighing canisters. Patients withdrawn if their acute attacks required treatment with systemic steroids.

END POINT

Control of asthma.

MEASUREMENTS AND MAIN RESULTS

Peak expiratory flow rate measured twice daily where cooperation allowed. Diary of symptoms and concomitant drug use kept daily. Results showed mean peak flow significantly higher (12% in mornings, 14% in evenings) in second three weeks of intervention compared with control period (95% confidence intervals 6.3-17.3% and 7.2-21.0%). Supplementary bronchodilator drugs reduced by 50% during intervention periods.

CONCLUSIONS

Budesonide given by Nebuhaler is effective prophylaxis for preschool children with frequent asthma.

Once a day theophylline in chronic childhood asthma?

The therapeutic effects of either morning or evening administration of a once-daily controlled release theophylline preparation (Uniphyllin) were studied in 17 asthmatic children. Neither morning nor evening administration produced therapeutic plasma theophylline levels throughout 24h. Similarly, bronchodilation was not maintained during the same period. However, morning peak expiratory flow rates were significantly improved following evening dosage, suggesting a role for evening administration when nocturnal symptoms predominate.

Cystic fibrosis: ultrasonographic findings in the pancreas and hepatobiliary system correlated with clinical data and pathology

Abdominal ultrasonography was performed on 35 adult patients with proven cystic fibrosis. Thirty-three patients showed pancreatic abnormalities. The most marked ultrasonographic features were increased parenchymal echogenicity, atrophy, non-visualisation of the duct and cyst formation. There was no correlation between these features and the severity of the pulmonary disease, the age of the patient, weight or glucose intolerance. Abnormalities of the biliary tract were demonstrated in nine (26%) patients and were associated with poor nutritional status. Multivariate analysis revealed a significant association between the following: hepatomegaly, increased liver echogenicity, splenomegaly, biliary disease; secondly, between lung function and serum albumin. Ultrasonography is useful in showing organ morphology but not in assessing disease severity.

Delivery of sodium cromoglycate by pressurized aerosol

Sodium cromoglycate (SCG) has recently been formulated as a pressurized aerosol. Twenty-five asthmatic outpatients taking SCG via the Spinhaler were studied in a double-dummy, double-blind cross-over trial in which subjects took Spincaps containing 20 mg of SCG for 2 months, and for the alternate 2 months were treated with SCG aerosol delivering 1 mg/actuation. There was no evidence of clinical deterioration occurring during the period on aerosol SCG. During this period however cough frequency was significantly lower and when data for the 8-13 and 14-46 year age groups were analysed separately, this decrease was seen to be confined to the younger group. Furthermore, this group but not the adults, showed a significant improvement in morning peak expiratory flow rate. We conclude that the aerosol preparation of SCG is a useful alternative to delivery by Spinhaler for patients who are able to coordinate, and that it may have special advantages for children.

Plasma terbutaline levels in asthma

Plasma terbutaline levels and peak expiratory flow rates were measured in 5 asthmatic children using doses of 0.25 and 0.075 mg/kg. The higher dose resulted in safe, non-toxic plasma levels and returned the peak expiratory flow rate to normal. This dose (maximum 5 mg) is safe in children.

The clinical and laboratory correlates of nasal polyps in cystic fibrosis

The clinical histories, chest X-ray appearances, skin prick test results, pulmonary function and IgE levels of 20 patients with cystic fibrosis (C.F.) complicated by nasal polyps have been compared with those of 97 C.F. controls. The patients who had developed polyps had a different clustering of symptoms to the controls with heavier birthweights, later presentations, milder gastrointestinal symptoms in infancy, less infection with Staphylococcus aureus and better vital capacities. There was no evidence on history, skin testing or IgE levels that the polyps patients were more allergic. It is likely, therefore, that nasal polyps in C.F. are due to a primary effect of the C.F. gene, although they could also be the effect of chronic nasal infection.

Salbutamol: tablets, inhalational powder, or nebuliser?

A study was carried out to ascertain the most effective method of giving salbutamol. Seventeen children with severe asthma received active salbutamol (4 mg via a nebuliser, 400 micrograms as an inhalational powder, or a 4 mg tablet) together with complementary placebos on a double-blind, triple-dummy randomly allocated basis. The bronchodilatation effect was assessed by measuring the peak expiratory flow rate. The bronchodilatation effect was greatest when patients received nebulised salbutamol (p less than 0.05) but lasted longest when they received the tablet (p less than 0.0001); the onset of the effect was rapid with all forms of administration. These results indicate that nebulised salbutamol gives the best relief in severe asthma; in less severe cases, however, a regimen combining the inhalational powder and tablets is sufficient and more convenient.

Shwachman's syndrome. A review of 21 cases

21 patients (10 male, 11 female) aged between 11 months and 29 years with Shwachman's syndrome are reviewed. All patients had exocrine pancreatic insufficiency. Haematological features included neutropenia in 19 (95%), anaemia in 10 (50%), and thrombocytopenia in 14 (70%); one patient developed erythroleukaemia. Severe infections occurred in 17 (85%) from which 3 (15%) died. Only one child exceeded the 3rd centile for height, and growth retardation was particularly evident in the older patients. All had skeletal abnormalities or delayed skeletal maturation, or both. Metaphyseal dyschondroplasia affected 13 of the older patients and was associated with skeletal deformities. Eight of 9 children under 2 1/2 years had rib abnormalities. Respiratory function tests in children under 2 years demonstrated reduced thoracic gas volume and chest wall compliance. Older patients had reduced forced expiratory volume and forced vital capacity. Neurological assessment showed developmental retardation or reduced IQ assessments, or both, in 85% of patients studied. Other neurological abnormalities included hypotonia, deafness, and retinitis pigmentosa. Neonatal problems had been present in 16 (80%) of the patients and 5 were of low birthweights. Hepatomegaly with biochemical evidence of liver involvement occurred in the younger patients and resolved with age. Other associated features included dental abnormalities, renal dysfunction, an icthyotic maculopapular rash in 13 (65%), delayed puberty, diabetes mellitus, and various dysmorphic features. These findings stress the diverse manifestations of the syndrome and extend knowledge on a number of aspects. Sibship segregation ratios support an autosomal mode of inheritance and an hypothesis for the pathophysiological basis of this syndrome is advanced.

Inhaled powder compared with aerosol administration of fenoterol in asthmatic children

Fenoterol as a powdered inhalation was shown to have a longer and stronger bronchodilator effect than the same dose inhaled from a standard metered dose aerosol in a double-blind double-placebo controlled cross-over study in 13 severely asthmatic children. The powder method of administration is free from many of the disadvantages of pressurised aerosols and may prove the method of choice in childhood.

Response to bronchial provocation and exercise in children with cystic fibrosis

Ten of fifteen cystic fibrosis children with positive skin prick tests to common antigens gave an immediate bronchial reaction to the antigen inhaled, five of them also gave a late reaction; however only one gave a history of asthma. The antigen most commonly eliciting a positive skin reaction in cystic fibrosis patients is Aspergillus fumigatus. In six children tested to this antigen the bronchial response varied, two were negative, one gave an immediate reaction and three gave a dual (immediate and late) reaction. None of the children showed the characteristic pattern of response to exercise seen in asthmatic patients, an initial rise in Peak Expiratory Flow Rate followed by a fall of greater than 14% below the resting level. Two patients showed an abnormal rise in Peak Expiratory Flow Rate during exercise, a pattern described previously in cystic fibrosis. The results suggest that bronchial allergy, immediate or late does completely explain susceptibility to asthma, and that other factors including perhaps the type of bronchial reactivity shown by bronchoconstriction after exercise may be required. However the majority of the children tested had bronchial allergy and anti-allergy therapy such as inhaled sodium cromoglycate may have a place in the management of selected patients with cystic fibrosis.

Cystic fibrosis, atopy, and airways lability

In a survey of cystic fibrosis (CF) in the Avon area, 48 children with CF from 40 families together with 71 of their parents were studied by spirometry, exercise tests, and pinch tests. A control group of 42 young adults was similarly tested; control data for children were taken from previously published work. The prevalence of atopy (any positive prick test) in children with CF was 48%. Sensitivity to grass pollens and house dust mite was no more common in these children (29%) than in a normal population (34%). Hypersensitivity to Aspergillus fumigatus was found in 35% of children with CF and was associated with severe lung disease. The parents had a normal pattern and prevalence of atopy. Exercise-induced airways obstruction was present in only 22% of children with CF; its association with severe lung disease rendered interpretation difficult. The parents had a normal response to exercise. Both hypersensitivity to A. fumigatus and exercise-induced airways lability had the features of acquired characteristics. There was nothing in the present study to support the hypothesis that the possession of a CF gene predisposed to atopy.

The relationship between chest radiographic scores and respiratory function tests in children with cystic fibrosis

Chest radiographic scores and respiratory function on 80 sets of results from 50 patients with Cystic Fibrosis were analyzed. Chest radiographic scores were assessed independently using the method of Chrispin and Norman. Respiratory function tests were found to correlate well with the chest radiographic score, the best correlation being with the forced expiratory volume in 0.75 sec. to forced vital capacity ratio F.E.V. 0.75/ F.V.C. (r = -0.674 n = 80 p less than 0.001).