Data in support for the measurement of serum 25-hydroxyvitamin D (25OHD) by tandem mass spectrometry

This article provides data and a method related to a research paper entitled “Assessing vitamin D nutritional status: is capillary blood adequate?” (Jensen et al., 2016) [1]. Circulating 25OHD, the accepted biomarker of the vitamin D nutritional status, is routinely measured by automated immunoassays, that although may be performed in hospital central laboratories, often suffer from a lack of specificity with regards to the different vitamin D metabolites, “Measurement of circulating 25-hydroxyvitamin D: a historical review” (Le Goff et al., 2015) [2]. Mass spectrometry offers this specificity. This article describes the performance of an in-house tandem mass spectrometry method for the individual measurement of 25OHD₃, 25OHD₂ and 3-épi-25OHD₃.

Assessing vitamin D nutritional status: Is capillary blood adequate?

BACKGROUND

Venous blood is the usual sample for measuring various biomarkers, including 25-hydroxyvitamin D (25OHD). However, it can prove challenging in infants and young children. Hence the finger-prick capillary collection is an alternative, being a relatively simple procedure perceived to be less invasive. We elected to validate the use of capillary blood sampling for 25OHD quantification by liquid chromatography tandem-mass spectrometry (LC/MS-MS).

METHODS

Venous and capillary blood samples were simultaneously collected from 15 preschool-aged children with asthma 10days after receiving 100,000IU of vitamin-D3 or placebo and 20 apparently healthy adult volunteers. 25OHD was measured by an in-house LC/MS-MS method.

RESULTS

The venous 25OHD values varied between 23 and 255nmol/l. The venous and capillary blood total 25OHD concentrations highly correlated (r(2)=0.9963). The mean difference (bias) of capillary blood 25OHD compared to venous blood was 2.0 (95% CI: -7.5, 11.5) nmol/l.

CONCLUSION

Our study demonstrates excellent agreement with no evidence of a clinically important bias between venous and capillary serum 25OHD concentrations measured by LC/MS-MS over a wide range of values. Under those conditions, capillary blood is therefore adequate for the measurement of 25OHD.

Determinants Of Oral corticosteroid Responsiveness in Wheezing Asthmatic Youth (DOORWAY): protocol for a prospective multicentre cohort study of children with acute moderate-to-severe asthma exacerbations

INTRODUCTION

Oral corticosteroids are the cornerstone of acute asthma management in the emergency department. Recent evidence has raised doubts about the efficacy of this treatment in preschool-aged children with viral-induced wheezing and in smoking adults. The aims of the study were to: (1) document the magnitude of response to oral corticosteroids in children presenting to the emergency department with moderate or severe asthma; (2) quantify potential determinants of response to corticosteroids and (3) explore the role of gene polymorphisms associated with the responsiveness to corticosteroids.

METHODS AND ANALYSIS

The design is a prospective cohort study of 1008 children aged 1-17 years meeting a strict definition of asthma and presenting with a clinical score of ≥4 on the validated Pediatric Respiratory Assessment Measure. All children will receive standardised severity-specific treatment with prednisone/prednisolone and cointerventions (salbutamol with/without ipratropium bromide). Determinants, namely viral aetiology, environmental tobacco smoke and single nucleotide polymorphism, will be objectively documented. The primary efficacy endpoint is the failure of emergency department (ED) management within 72 h of the ED visit. Secondary endpoints include other measures of asthma severity and time to recovery within 7 days of the index visit. The study has 80% power for detecting a risk difference of 7.5% associated with each determinant from a baseline risk of 21%, at an α of 0.05.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from all participating institutions. An impaired response to systemic steroids in certain subgroups will challenge the current standard of practice and call for the immediate search for better approaches. A potential host-environment interaction will broaden our understanding of corticosteroid responsiveness in children. Documentation of similar effectiveness of corticosteroids across determinants will provide the needed reassurance regarding current treatment recommendations.

RESULTS

Results will be disseminated at international conferences and manuscripts targeted at emergency physicians, paediatricians, geneticists and respirologists.

TRIAL REGISTRATION NUMBER

This study is registered at Clinicaltrials.gov (NCT02013076).

Asthma action plans are highly variable and do not conform to best visual design practices

BACKGROUND

Asthma action plans improve asthma outcomes and are recommended in guidelines. However, delivery by physicians and usage by patients remain low. This may be because of variability in existing plans and a failure to consider visual design and usability factors in plan development.

OBJECTIVE

To characterize the variability in both the content and the format of existing plans, and the extent to which their format conforms to evidence-based visual design recommendations.

METHODS

We collected plans from the internet, Canadian experts and associations, guidelines, and published trials. We inductively developed analytic criteria for format and content analyses.

RESULTS

We collected 69 unique English or French-language adult outpatient plans from around the world. We found large variability in format, and plans fulfilled a mean of only 3.5 out of 8 evidence-based visual design recommendations. Content was also variable, including different descriptions of the baseline clinical state and descriptions and instructions at each "action point" (point recommending a change in treatment).

CONCLUSION

Existing plans vary widely in content and format. Accordingly, studies evaluating the effectiveness of action plans may not be directly comparable. Also, visual design may affect usability, uptake, and effectiveness. Our results suggest that this has not been adequately addressed in most plans, and design evidence and experts should be included in future development.

Doctor shopping before and after a visit to a paediatric emergency department

BACKGROUND

Use of multiple care providers is known to be associated with poor continuity of care.

OBJECTIVES

To estimate the prevalence of and identify risk factors for doctor shopping by parents of children with common acute illnesses seen in the emergency department (ED) of a children's hospital.

SETTING

ED at the Montreal Children's Hospital (MCH), Montreal, Quebec.

METHODS

Doctor shopping was defined as visiting three or more different care sites (the MCH ED, other EDs, outpatient clinics or private offices) for a single illness episode, including all visits occurring within successive 72 h periods up to a maximum of 15 days before and after an ED visit from April 1995 to March 1996. Logistic regression was used to compare characteristics of illness episodes with doctor shopping versus those without.

RESULTS

Of the total 40,150 visits during the study period, doctor shopping was observed in 18% of the visits. The risk of doctor shopping was positively associated with an initial visit at other EDs (odds ratio [OR] 9.08, 95% CI 7.16 to 11.52), outpatient clinics (OR 4.47, 95% CI 3.71 to 5.37) or private offices (OR 1.71, 95% CI 1.48 to 1.96) versus those who visited the MCH ED first. The risk did not differ according to whether a paediatrician versus a general practitioner saw the child during the initial visit (OR 0.99, 95% CI 0.86 to 1.15). Some diagnoses (the reference category was upper respiratory infection), including urinary tract infection (OR 3.31, 95% CI 2.58 to 4.23) and gastroenteritis (OR 1.59, 95% CI 1.35 to 1.88), were associated with an increased risk of doctor shopping, while asthma was associated with a reduced risk (OR 0.71, 95% CI 0.60 to 0.86).

CONCLUSION

Doctor shopping is common among parents of children with acute illnesses. Parents of children who were seen in the MCH ED first were less likely to doctor shop, perhaps because the parents were more confident about the advice and treatment received. Further research should investigate the underlying reasons for doctor shopping, eg, services other than an ED were not available and parents' perceptions of the quality of health services.

Canadian Thoracic Society Asthma Management Continuum--2010 Consensus Summary for children six years of age and over, and adults

BACKGROUND/OBJECTIVE

To integrate new evidence into the Canadian Asthma Management Continuum diagram, encompassing both pediatric and adult asthma.

METHODS

The Canadian Thoracic Society Asthma Committee members, comprised of experts in pediatric and adult respirology, allergy and immunology, emergency medicine, general pediatrics, family medicine, pharmacoepidemiology and evidence-based medicine, updated the continuum diagram, based primarily on the 2008 Global Initiative for Asthma guidelines, and performed a focused review of literature pertaining to key aspects of asthma diagnosis and management in children six years of age and over, and adults.

RESULTS

In patients six years of age and over, management of asthma begins with establishing an accurate diagnosis, typically by supplementing medical history with objective measures of lung function. All patients and caregivers should receive self-management education, including a written action plan. Inhaled corticosteroids (ICS) remain the first-line controller therapy for all ages. When asthma is not controlled with a low dose of ICS, the literature supports the addition of long-acting beta2-agonists in adults, while the preferred approach in children is to increase the dose of ICS. Leukotriene receptor antagonists are acceptable as second-line monotherapy and as an alternative add-on therapy in both age groups. Antiimmunoglobulin E therapy may be of benefit in adults, and in children 12 years of age and over with difficult to control allergic asthma, despite high-dose ICS and at least one other controller.

CONCLUSIONS

The foundation of asthma management is establishing an accurate diagnosis based on objective measures (eg, spirometry) in individuals six years of age and over. Emphasis is placed on the similarities and differences between pediatric and adult asthma management approaches to achieve asthma control.

WITHDRAWN: Cow's milk protein avoidance and development of childhood wheeze in children with a family history of atopy

BACKGROUND

In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease, when breast-feeding is not possible or supplemental feeding is needed. Most infant formulas are based on cow's milk protein. Alternative choices include soya based and hydrolysed cows milk formulas.

OBJECTIVES

To estimate the effect of dietary avoidance of cow's milk protein on the development of asthma or wheeze in children.

SEARCH STRATEGY

We searched the Cochrane database for eligible trials until February 2002. We obtained the full text papers of all abstracts identified as RCTs and two reviewers independently reviewed them.

SELECTION CRITERIA

We included randomised controlled trials involving children with a family history of atopy in at least one first degree relative, if feeding with cow's milk based standard formula was compared to dietary avoidance of cow's milk protein, using soya or other hypoallergenic formula during the initial four months of life or longer.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. A priori defined subgroups were the types of hypoallergenic artificial feed and dietary restrictions on mother and/or child's diet.

MAIN RESULTS

Six trials used hydrolysed formula for at least four months, in addition to dietary restrictions and in some cases dust-mite reduction measures. The risk of infants experiencing asthma or wheeze during the first year of life was reduced compared to standard cow's milk based formula (Relative Risk 0.40, 95% Confidence Intervals 0.19 to 0.85). Feeding soya-based formula as opposed to standard cow's milk formula did not reduce the risk of having asthma or wheeze at any age.

AUTHORS' CONCLUSIONS

Breast-milk should remain the feed of choice for all babies. In infants with at least one first degree relative with atopy, hydrolysed formula for a minimum of four months combined with dietary restrictions and environment measures may reduce the risk of developing asthma or wheeze in the first year of life. There is insufficient evidence to suggest that soya-based milk formula has any benefit.

Corticosteroids for preventing relapse following acute exacerbations of asthma

BACKGROUND

Acute asthma is responsible for many emergency department (ED) visits annually. Between 12 to 16% will relapse to require additional interventions within two weeks of ED discharge. Treatment of acute asthma is based on rapid reversal of bronchospasm and reducing airway inflammation.

OBJECTIVES

To determine the benefit of corticosteroids (oral, intramuscular, or intravenous) for the treatment of asthmatic patients discharged from an acute care setting (i.e. usually the emergency department) after assessment and treatment of an acute asthmatic exacerbation.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register and reference lists of articles. In addition, authors of all included studies were contacted to locate unpublished studies. The most recent search was run in October 2006.

SELECTION CRITERIA

Randomized controlled trials comparing two types of corticosteroids (oral, intra-muscular, or inhaled) with placebo for outpatient treatment of asthmatic exacerbations in adults or children.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Six trials involving 374 people were included. One study used intramuscular corticosteroids, five studies used oral corticosteroids. The review was split into two reviews and although the latest search yielded no additional placebo controlled trials an additional IM study was included. Significantly fewer patients in the corticosteroid group relapsed to receive additional care in the first week (Relative risk (RR) 0.38; 95% confidence interval (CI) 0.2 to 0.74). This favourable effect was maintained over the first 21 days (RR 0.47; 95% CI 0.25 to 0.89) and there were fewer subsequent hospitalizations (RR 0.35; 95% CI 0.13 to 0.95). Patients receiving corticosteroids had less need for beta(2)-agonists (mean difference (MD) -3.3 activations/day; 95% CI -5.6 to -1.0). Changes in pulmonary function tests (SMD 0.045; 95% CI -0.47 to 0.56) and side effects (SMD 0.03; 95% CI -0.38 to 0.44) in the first 7 to 10 days, while rarely reported, showed no significant differences between the treatment groups. Statistically significant heterogeneity was identified for the side effect results; all other outcomes were homogeneous. From these results, as few as ten patients need to be treated to prevent relapse to additional care after an exacerbation of asthma.

AUTHORS' CONCLUSIONS

A short course of corticosteroids following assessment for an asthma exacerbation significantly reduces the number of relapses to additional care, hospitalizations and use of short-acting beta(2)-agonist without an apparent increase in side effects. Intramuscular and oral corticosteroids are both effective.

Long-acting beta2-agonists versus anti-leukotrienes as add-on therapy to inhaled corticosteroids for chronic asthma

BACKGROUND

Patients who continue to experience asthma symptoms despite taking regular inhaled corticosteroids (ICS) represent a management challenge. Leukotriene receptor antagonists (LTRA) and long-acting beta(2)-agonists (LABA) agents may both be considered as add-on therapy to inhaled corticosteroids (ICS).

OBJECTIVES

We compared the efficacy and safety profile of adding either daily LABA or LTRA in asthmatic patients who remained symptomatic on ICS.

SEARCH STRATEGY

The Cochrane Airways Group Specialised Register was searched for randomised controlled trials up to and including March 2006. Reference lists of all included studies and reviews were screened to identify potentially relevant citations. Inquiries regarding other published or unpublished studies supported by the authors of the included studies or pharmaceutical companies who manufacture these agents were made. Conference proceedings of major respiratory meetings were also searched.

SELECTION CRITERIA

Only randomised controlled trials conducted in adults or children with recurrent asthma where a LABA (for example, salmeterol or formoterol) or LTRA (for example, montelukast, pranlukast, zafirlukast) was added to ICS for a minimum of 28 days were considered for inclusion. Inhaled short-acting beta(2)-agonists and short courses of oral steroids were permitted as rescue medications. Other daily asthma treatments were permitted, providing the dose remained constant during the intervention period. Two reviewers independently reviewed the literature searches.

DATA COLLECTION AND ANALYSIS

Data extraction and trial quality assessment were conducted independently by two reviewers. Whenever possible, primary study authors were requested to confirm methodology and data extraction and to provide additional information and clarification when needed. Where necessary, expansion of graphic reproductions and estimation from other data presented in the paper was performed.

MAIN RESULTS

Fifteen randomised controlled trials met the inclusion criteria; eleven trials including 6,030 participants provided data in sufficient detail to permit aggregation. All eleven trials pertained to adults with moderate airway obstruction (% predicted FEV(1) 66-76%) at baseline. Montelukast (n=9) or Zafirlukast (n=2) was compared to Salmeterol (n=9) or Formoterol (n=2) as add-on therapy to 400-565 mcg of beclomethasone or equivalent. Risk of exacerbations requiring systemic corticosteroids was significantly lower with LABA+ICS when compared to LTRA+ICS (RR= 0.83, 95% Confidence Interval (95%CI): 0.71, 0.97): the number needed to treat with LABA compared to LTRA, to prevent one exacerbation over 48 weeks, was 38 (95% CI: 23 to 247). The following outcomes also improved significantly with the addition of LABA compared to LTRA to inhaled steroids (Weighted Mean Difference; 95%CI): morning PEFR (16 L/min; 13 to 18), evening PEFR (12 L/min; 9 to 15), FEV(1) (80 mL; 60 to 100), rescue-free days (9%; 5% to 13%), symptom-free days (6%; 2 to 11), rescue beta(2)-agonists (-0.5 puffs/day; -0.2 to -1), quality of life (0.1; 0.05 to 0.2), symptom score (Standard Mean Difference -0.2; -0.1 to -0.3), night awakenings (-0.1/week; -0.06 to -0.2) and patient satisfaction (RR 1.12; 1.07 to 1.16). Risk of withdrawals due to any reason was significantly lower with LABA+ICS compared to LTRA+ICS (Risk Ratio 0.83, 95% CI 0.73 to 0.95). Withdrawals due to adverse events or due to poor asthma control, hospitalisation, osteopenia, serious adverse events, overall adverse events, headache or cardiovascular events were not significantly different between the two study groups.

AUTHORS' CONCLUSIONS

In asthmatic adults inadequately controlled on low doses of inhaled steroids, the addition of LABA is superior to LTRA for preventing exacerbations requiring systemic steroids, and for improving lung function, symptoms, and the use of rescue beta(2)-agonists.

Written action plans for asthma in children

BACKGROUND

While all asthma consensus statements recommend the use of written action plan (WAP) as a central part of asthma management, a recent systematic review of randomised trials highlighted the paucity of trials where the only difference between groups was the provision or not of a written action plan.

OBJECTIVES

The objectives of this review were firstly to evaluate the independent effect of providing versus not providing a written action plan in children and adolescents with asthma, and secondly to compare the effect of different written action plans.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (November 2004), which is derived from searches of CENTRAL, MEDLINE, EMBASE, CINAHL, as well as handsearched respiratory journals, and meeting abstracts. We also searched bibliographies of included studies and identified review articles.

SELECTION CRITERIA

Randomised controlled trials were included if they compared a written action plan with no written action plan, or different written action plans with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials, assessed trial quality and extracted the data. Study authors were contacted for additional information.

MAIN RESULTS

Four trials (three RCTs and one quasi-RCT) involving 355 children were included. Children using symptom-based WAPs had lower risk of exacerbations which required an acute care visit (N = 5; RR 0.73; 95% CI 0.55 to 0.99). The number needed to treat to prevent one acute care visit was 9 (95% CI 5 to 138). Symptom monitoring was preferred over peak flow monitoring by children (N = 2; RR 1.21; 95% CI 1.00 to 1.46), but parents showed no preference (N = 2; RR 0.96; 95% CI 0.18 to 2.11). Children assigned to peak flow-based action plans reduced by 1/2 day the number of symptomatic days per week (N = 2; mean difference: 0.45 days/week; 95% CI 0.04 to 0.26). There were no significant group differences in the rate of exacerbation requiring oral steroids or admission, school absenteeism, lung function, symptom score, quality of life, and withdrawals.

AUTHORS' CONCLUSIONS

The evidence suggests that symptom-based WAP are superior to peak flow WAP for preventing acute care visits although there is insufficient data to firmly conclude whether the observed superiority is conferred by greater adherence to the monitoring strategy, earlier identification of onset of deteriorations, higher threshold for presentation to acute care settings, or the specific treatment recommendations.

Inhaled corticosteroids versus sodium cromoglycate in children and adults with asthma

BACKGROUND

Inhaled corticosteroids (ICS) and sodium cromoglycate (SCG) have become established as effective controller medications for children and adults with asthma, but their relative efficacy is not clear.

OBJECTIVES

To compare the relative effectiveness and adverse effects of ICS and SCG among children and adults with chronic asthma.

SEARCH STRATEGY

Systematic search of the Cochrane Airways Group's special register of controlled trials (to Feb. 2004), hand searches of the reference lists of included trials and relevant review papers, and written requests for identification of additional trials from pharmaceutical manufacturers.

SELECTION CRITERIA

Randomized controlled trials comparing the effect of ICS with SCG in children and adults with chronic asthma.

DATA COLLECTION AND ANALYSIS

All studies were assessed independently for eligibility by three review authors. Disagreements were settled by consensus. Trial authors were contacted to supply missing data or to verify methods. Eligible studies were abstracted and fixed- and random-effects models were implemented to pool studies. Separate analyses were conducted for paediatric and adult studies. Subgroup analyses and meta-regression models were fit to explore heterogeneity of lung function outcomes by type of RCT, category of ICS or SCG dosage, asthma severity of participants, and study quality on outcomes.

MAIN RESULTS

Of 67 identified studies, 17 trials involving 1279 children and eight trials involving 321 adults with asthma were eligible. Thirteen (76%) of the paediatric studies and six (75%) of the adult studies were judged to be high quality. Among children, ICS were associated with a higher final mean forced expiratory volume in 1 second [FEV1] (weighted mean difference [WMD] 0.07 litres, 95% confidence interval [CI] 0.02 to 0.11) and higher mean final peak expiratory flow rate [PEF] (WMD 17.3 litres/minute, 95% CI 11.3 to 23.3) than SCG. In addition, ICS were associated with fewer exacerbations (WMD -1.18 exacerbations per year, 95% CI -2.15 to - 0.21), lower asthma symptom scores, and less rescue bronchodilator use than SCG. There were no group differences in the proportion of children with adverse effects. Among adults, ICS were similarly associated with a higher mean final FEV1 (WMD 0.21 litres, 95% CI 0.13 to 0.28) and a higher final endpoint PEF (WMD 28.2 litres/minute, 95% CI 18.7 to 37.6) than SCG. ICS were also associated with fewer exacerbations (WMD -3.30 exacerbations per year, 95% CI -5.62 to -0.98), lower asthma symptom scores among cross-over trials but not parallel trials, and less rescue bronchodilator use than SCG. There were no differences in the proportion of adults with adverse effects. In subgroup analyses involving lung function measures, paediatric and adult studies judged to be of high quality had results consistent with the overall results. Lung function measures in children were higher in studies with medium BDP-equivalent steroid dosages than low BDP-equivalent dosages, while adult studies could not be compared by steroid dosage since they all incorporated similar dosages. There were no significant differences in lung function by the asthma severity of participants for adult or child studies.

AUTHORS' CONCLUSIONS

ICS were superior to SCG on measures of lung function and asthma control for both adults and children with chronic asthma. There were few studies reporting on quality of life and health care utilization, which limited our ability to adequately evaluate the relative effects of these medications on a broader range of outcomes. Although there were no differences in adverse effects between ICS and SCG, most trials were short and may not have been of sufficient duration to identify long-term effects. Our results support recent consensus statements in the U.S. and elsewhere that favour the use of ICS over SCG for control of persistent asthma.

Oral xanthines as maintenance treatment for asthma in children

BACKGROUND

Xanthines have been used in the treatment of asthma as a bronchodilator, though they may also have anti-inflammatory effects. The current role of xanthines in the long-term treatment of childhood asthma needs to be reassessed.

OBJECTIVES

To determine the efficacy of xanthines (e.g. theophylline) in the maintenance treatment of paediatric asthma.

SEARCH STRATEGY

A search of the Cochrane Airways Group Specialised Register was undertaken with predefined search terms. Searches are current to May 2005.

SELECTION CRITERIA

Randomised controlled trials,lasting at least four weeks comparing a xanthine with placebo, regular short-acting beta-agonist (SABA), inhaled corticosteroids (ICS), cromoglycate (SCG), ketotifen (KET) or leukotriene antagonist, in children with diagnosed with chronic asthma between 18 months and 18 years old.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected each study for inclusion in the review and extracted data. Primary outcome was percentage of symptom-free days.

MAIN RESULTS

Thirty-four studies (2734 participants) of adequate quality were included. Xanthine versus placebo (17 studies): The proportion of symptom free days was larger with xanthine compared with placebo (7.97% [95% CI 3.41, 12.53]). Rescue medication usage was lower with xanthine, with no significant difference in symptom scores or hospitalisations. FEV1 , and PEF were better with xanthine. Xanthine was associated with non - specific side-effects. Data from behavioural scores were inconclusive. Xanthine versus ICS (four studies) : Exacerbations were less frequent with ICS, but no significant difference on lung function was observed. Individual studies reported significant improvements in symptom measures in favour of steroids, and one study reported a difference in growth rate in favour of xanthine. No difference was observed for study withdrawal or tremor. Xanthine was associated with more frequent headache and nausea. Xanthine versus regular SABA (10 studies): No significant difference in symptoms, rescue medication usage and spirometry. Individual studies reported improvement in PEF with beta-agonist. Beta-agonist treatment led to fewer hospitalisations and headaches. Xanthine was associated with less tremor. Xanthine versus SCG (six studies ): No significant difference in symptoms, exacerbations and rescue medication. Sodium cromoglycate was associated with fewer gastro-intestinal side-effects than xanthine. Xanthine versus KET (one study): No statistical tests of significance between xanthine and ketotifen were reported. Xanthine + ICS versus placebo + same dose ICS (three studies) : Results were conflicting due to clinical/methodological differences, and could not be aggregated.

AUTHORS' CONCLUSIONS

Xanthines as first-line preventer alleviate symptoms and reduce requirement for rescue medication in children with mild to moderate asthma. When compared with ICS they were less effective in preventing exacerbations. Xanthines had similar efficacy as single preventative agent compared with regular SABA and SCG. Evidence on AEs (adverse effects) was equivocal: there was evidence for increased AEs overall, but no evidence that any specific AE (including effects on behaviour and attention) occurred more frequently than with placebo. There is insufficient evidence from available studies to make firm conclusions about the effectiveness of xanthines as add-on preventative treatment to ICS, and there are no published paediatric studies comparing xanthines with alternatives in this role. Our data suggest that xanthines are only suitable as first-line preventative asthma therapy in children when ICS are not available. They may have a role as add-on therapy in more severe asthma not controlled by ICS, but further studies are needed to examine this, and to define the risk-benefit ratio compared with other agents.

Long-acting beta2-agonists versus placebo in addition to inhaled corticosteroids in children and adults with chronic asthma

BACKGROUND

Long-acting inhaled beta2-adrenergic agonists are recommended as 'add-on' medication to inhaled corticosteroids in the maintenance therapy of asthmatic adults and children aged two years and above.

OBJECTIVES

To quantify in asthmatic patients the safety and efficacy of the addition of long-acting beta2-agonists to inhaled corticosteroids on the incidence of asthma exacerbations, pulmonary function and other measures of asthma control.

SEARCH STRATEGY

We identified randomised controlled trials (RCTs) through electronic database searches (the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE and CINAHL), bibliographies of RCTs and correspondence with manufacturers, until April 2004.

SELECTION CRITERIA

RCTs were included that compared the addition of inhaled long-acting beta2-agonists to corticosteroids with inhaled corticosteroids alone for asthma therapy in children aged two years and above and in adults.

DATA COLLECTION AND ANALYSIS

Studies were assessed independently by two review authors for methodological quality and data extraction. Confirmation was obtained from the trialists when possible. The primary endpoint was rate of asthma exacerbations requiring systemic corticosteroids. Secondary endpoints included pulmonary function tests (PFTs), symptom scores, adverse events and withdrawal rates.

MAIN RESULTS

Of 594 identified citations, 49 trials met the inclusion criteria: 27 full-text publications, one unpublished full-text report and 21 abstracts. Twenty-three citations (21 abstracts and two full-text publications) provided data in insufficient detail, 26 trials contributed to this systematic review. All but three trials were of high methodological quality. Most interventions (N = 26) were of four-month duration or less. Eight trials focused on children and 18 on adults, with participants generally symptomatic with moderate airway obstruction despite their current inhaled steroid regimen. If a trial had more than one intervention or control group, additional control to intervention comparisons were considered separately. Formoterol (N = 17) or salmeterol (N = 14) were most frequently added to low-dose inhaled corticosteroids (200 to 400 microg/day of beclomethasone (BDP) or equivalent). The addition of a daily long-acting beta2-agonist (LABA) reduced the risk of exacerbations requiring systemic steroids by 19% (relative risk (RR) 0.81, 95% CI 0.73 to 0.90). The number needed to treat for one extra patient to be free from exacerbation for one year was 18 (95% CI 13 to 33). The addition of LABA significantly improved FEV1 (weighted mean difference (WMD) 170 mL, 95% CI 110 to 240) using a random-effects model, increased the proportion of symptom-free days (WMD 17%, 95% CI 12 to 22, N = 6 trials) and rescue-free days (WMD 19%, 95% CI 12 to 26, N = 2 trials). The group treated with LABA plus inhaled corticosteroid showed a reduction in the use of rescue short-acting beta2-agonists (WMD -0.7 puffs/day, 95% CI -1.2 to -0.2), experienced less withdrawals due to poor asthma control (RR 0.5, 95% CI 0.4 to 0.7) and less withdrawals due to any reason (RR 0.9, 95% CI 0.8 to 0.98), using a random-effects model. There was no group difference in risk of overall adverse effects (RR 0.98, 95% CI 0.92 to 1.05), withdrawals due to adverse health events (RR 1.29, 95% CI 0.96 to 1.75) or specific adverse health events.

AUTHORS' CONCLUSIONS

In patients who are symptomatic on low to high doses of inhaled corticosteroids, the addition of a long-acting beta2-agonist reduces the rate of exacerbations requiring systemic steroids, improves lung function, symptoms and use of rescue short-acting beta2-agonists. The similar number of serious adverse events and withdrawal rates in both groups provides some indirect evidence of the safety of long-acting beta2-agonists as add-on therapy to inhaled corticosteroids.

Combination of inhaled long-acting beta2-agonists and inhaled steroids versus higher dose of inhaled steroids in children and adults with persistent asthma

BACKGROUND

In asthmatic patients inadequately controlled on inhaled corticosteroids and/or those with moderate persistent asthma, two main options are recommended: the combination of a long-acting inhaled beta2 agonist (LABA) with inhaled corticosteroids (ICS) or use of a higher dose of inhaled corticosteroids.

OBJECTIVES

To determine, in asthmatic patients, the effect of the combination of long-acting beta2 agonists and inhaled corticosteroids compared to a higher dose of inhaled corticosteroids on the incidence of asthma exacerbations, on pulmonary function and on other measures of asthma control and to look for characteristics associated with greater benefit for either treatment option.

SEARCH STRATEGY

We identified randomized controlled trials (RCTs) through electronic database searches (MEDLINE, EMBASE and CINAHL), bibliographies of RCTs and correspondence with manufacturers until April 2004.

SELECTION CRITERIA

RCTs were included that compared the combination of inhaled LABA and ICS to a higher dose of inhaled corticosteroids, in children aged 2 years and older, and in adults with asthma.

DATA COLLECTION AND ANALYSIS

Studies were assessed independently by two authors for methodological quality and data extraction. Confirmation was obtained from the trialists when possible. The primary endpoint was rate of patients experiencing one or more asthma exacerbations requiring oral corticosteroids. Secondary endpoints included pulmonary function tests (PFTs), symptoms, use of rescue beta2 agonists, adverse events and withdrawal rates. The meta-analysis was done with RevMan Analyses and the meta-regression, with Stata.

MAIN RESULTS

Of 593 citations identified, 30 (three pediatric; 27 adult) trials were analysed recruiting 9509 participants, including one study providing two control-intervention comparisons. Only one trial included corticosteroid-naive patients. Participants were symptomatic, generally (N=20 trials) presenting with moderate (FEV1 60-79% of predicted) rather than mild airway obstruction. Trials tested the combination of salmeterol (N=22) or formoterol (N=8) with a median of 400 mcg of beclomethasone or equivalent (BDP-eq) compared to a median of 800 to 1000 mcg/day of BDP-eq. Trial duration was 24 weeks or less in all but four trials. There was no significant group difference in the rate of patients with exacerbations requiring systemic corticosteroids [N=15, RR=0.88 (95% CI: 0.77, 1.02)]. The combination of LABA and ICS resulted in greater improvement from baseline in FEV1 [N=7, WMD=0.10 L (95% CI: 0.07, 0.12)], in symptom-free days [N=8 , WMD=11.90% (95% CI:7.37, 16.44), random effects model], and in the daytime use of rescue beta2 agonists than a higher dose of ICS [N=4, WMD= -0.99 puffs/day (95% CI: -1.41, -0.58), random effects model]. There was no significant group difference in the rate of overall adverse events [N=15, RR=0.93 (95% CI: 0.84, 1.03), random effects model], or specific side effects, with the exception of a three-fold increase rate of tremor in the LABA group [N= 10, RR=2.96 (95%CI: 1.60, 5.45)]. The rate of withdrawals due to poor asthma control favoured the combination of LABA and ICS [N=20, RR=0.69 (95%CI: 0.52, 0.93)].

AUTHORS' CONCLUSIONS

In adult asthmatics, there was no significant difference between the combination of LABA and ICS and a higher dose of ICS for the prevention of exacerbations requiring systemic corticosteroids. Overall, the combination therapy led to greater improvement in lung function, symptoms and use of rescue beta2 agonists, (although most of the results are from trials of up to 24 weeks duration). There were less withdrawals due to poor asthma control in this group than when using a higher dose of inhaled corticosteroids. Apart from an increased rate of tremor, the two options appear safe although adverse effects associated with long-term ICS treatment were seldom monitored.

Intravenous aminophylline for acute severe asthma in children over two years receiving inhaled bronchodilators

BACKGROUND

Since the advent of inhaled beta2-agonists, anticholinergic agents and glucocorticoids, the role of aminophylline in paediatric acute asthma has become less clear. There remains some consensus that it is beneficial in children with acute severe asthma, receiving maximised therapy (oxygen, inhaled bronchodilators, and glucocorticoids).

OBJECTIVES

To determine if the addition of intravenous aminophylline produces a beneficial effect in children with acute severe asthma receiving conventional therapy.

SEARCH STRATEGY

The Cochrane Airways Group register of trials was used to identify relevant studies. The latest search was carried out in December 2004

SELECTION CRITERIA

Randomised-controlled trials comparing intravenous aminophylline with placebo in addition to usual care in children met the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies and extracted data. Disagreement in the selection of trials was resolved by consensus. Attempts were made to contact authors to verify accuracy of data.

MAIN RESULTS

Seven trials met the inclusion criteria (380 participants). Methodological quality was high. All studies recruited children with acute severe asthma and requiring hospital admission. Six studies sought participants who were unresponsive to nebulised short-acting beta-agonist and administered systemic steroids to study participants. In two studies where some children were able to perform spirometry, baseline FEV1 was between 35 and 45% predicted. The addition of aminophylline to steroids and beta2-agonist significantly improved FEV1% predicted over placebo at 6-8 hours, 12-18 hours and 24 hours. Aminophylline led to a greater improvement in PEF% predicted over placebo at 12-18 hours. There was no significant difference in length of hospital stay, symptoms, frequency of nebulsations and mechanical ventilation rates. There were insufficient data to permit aggregation for oxygenation and duration of supplemental oxygen therapy. Aminophylline led to a three-fold increase in the risk of vomiting. There was no significant difference between treatment groups with regard to hypokalaemia, headaches, tremour, seizures, arrhythmias and deaths.

AUTHORS' CONCLUSIONS

In children with a severe asthma exacerbation, the addition of intravenous aminophylline to beta2-agonists and glucocorticoids (with or without anticholinergics) improves lung function within 6 hours of treatment. However there is no apparent reduction in symptoms, number of nebulised treatment and length of hospital stay. There is insufficient evidence to assess the impact on oxygenation, PICU admission and mechanical ventilation. Aminophylline is associated with a significant increased risk of vomiting.

Addition of inhaled long-acting beta2-agonists to inhaled steroids as first line therapy for persistent asthma in steroid-naive adults

BACKGROUND

Consensus statements recommend the addition of long-acting inhaled beta2-agonists only in asthmatic patients who are inadequately controlled on inhaled corticosteroids.

OBJECTIVES

To compare the efficacy of initiating anti-inflammatory therapy using the combination of inhaled corticosteroids and long-acting beta2-agonists (ICS+LABA) as compared to inhaled corticosteroids alone (ICS alone) in steroid-naive children and adults with persistent asthma.

SEARCH STRATEGY

We identified randomised controlled trials (RCTs) through electronic database searches (Cochrane Airways Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and CINAHL) until April 2004, bibliographies of identified RCTs and correspondence with manufacturers.

SELECTION CRITERIA

RCTs comparing the combination of inhaled corticosteroids and long-acting beta2-agonists (ICS + LABA) to inhaled corticosteroids (ICS) alone in steroid-naive children and adults with asthma.

DATA COLLECTION AND ANALYSIS

Studies were assessed independently by each reviewer for methodological quality and data extraction. Confirmation was obtained from the trialists when possible. The primary endpoint was rate of asthma exacerbations requiring systemic corticosteroids. Secondary endpoints included pulmonary function tests (PFTs), symptoms, use of other measures of asthma control, adverse events, and withdrawal rates.

MAIN RESULTS

Eighteen trials met the inclusion criteria; nine (totaling 1061 adults) contributed sufficient data to be analysed. Baseline forced expiratory volume in one minute (FEV1) was less than 80% predicted value in four trials and equal to or greater than 80% in five trials. The long-acting beta2-agonists (LABA) formoterol (N=2) or salmeterol (N=7) were added to a dose of at least 800 microg/day of beclomethasone dipropionate (BDP) equivalent of inhaled corticosteroids (ICS) in three trials and to at least 400 microg/day in the six remaining trials. Treatment with ICS plus LABA was not associated with a lower risk of exacerbations requiring oral corticosteroids than ICS alone (relative risk (RR) 1.2; 95% confidence interval (CI) 0.8 to 1.9). FEV1 improved significantly with LABA (weighted mean difference (WMD) 210 ml; 95% CI 120 to 300), as did symptom-free days (WMD 10.74%; 95% CI 1.86 to 19.62), but the change in use of rescue fast-acting beta2-agonists was not significantly different between the groups (WMD -0.4 puff/day, 95% CI -0.9 to 0.1). There was no significant group difference in adverse events (RR 1.1; 95% CI 0.8 to 1.5), withdrawals (RR 0.9; 95% CI 0.6 to 1.2), or withdrawals due to poor asthma control (RR 1.3; 95% CI 0.5 to 3.4).

AUTHORS' CONCLUSIONS

In steroid-naive patients with mild to moderate airway obstruction, the initiation of inhaled corticosteroids in combination with long-acting beta2-agonists does not significantly reduce the rate of exacerbations over that achieved with inhaled corticosteroids alone; it does improve lung function and symptom-free days but does not reduce rescue beta2-agonist use as compared to inhaled steroids alone. Both options appear safe. There is insufficient evidence at present to recommend use of combination therapy rather than ICS alone as a first-line treatment.

Long-acting beta2-agonists versus anti-leukotrienes as add-on therapy to inhaled corticosteroids for chronic asthma

BACKGROUND

Patients who continue to experience asthma symptoms despite taking regular inhaled corticosteroids (ICS) represent a management challenge. Leukotriene receptor antagonists (LTRA) and long-acting beta2-agonists (LABA) agents may both be considered as add-on therapy to inhaled corticosteroids (ICS).

OBJECTIVES

We compare the efficacy and safety profile of adding either daily LABA or LTRA in asthmatic patients with asthma who remained symptomatic on ICS.

SEARCH STRATEGY

MEDLINE, EMBASE, CINAHL databases were searched for randomised controlled trials up to and including January 2004. Reference lists of all included studies and reviews were screened to identify potentially relevant citations. Inquiries regarding other published or unpublished studies supported by the authors of the included studies or pharmaceutical companies who manufacture these agents were made. Conference proceedings of major respiratory meetings were also searched.

SELECTION CRITERIA

Only randomised controlled trials conducted in adults or children with recurrent asthma where a LABA (for example, salmeterol or formoterol) or LTRA (for example, montelukast, pranlukast, zafirlukast) was added to ICS for a minimum of 28 days were considered for inclusion. Inhaled short-acting beta2-agonists and short courses of oral steroids were permitted as rescue medications. Other daily asthma treatments were permitted, providing the dose remained constant during the intervention period. Two reviewers independently reviewed the literature searches.

DATA COLLECTION AND ANALYSIS

Data extraction and trial quality assessment were conducted independently by two reviewers. Whenever possible, primary study authors were requested to confirm methodology and data extraction and to provide additional information and clarification when needed. Where necessary, expansion of graphic reproductions and estimation from other data presented in the paper was performed.

MAIN RESULTS

Twelve randomised controlled trials met the inclusion criteria; only eight trials including 5,895 patients, provided data in sufficient details to allow aggregation. All eight trials pertained to adults with moderate airway obstruction (% predicted FEV1 66-76%) at baseline. Montelukast (n=6) or Zafirlukast (n=2) was compared to Salmeterol (n=7) or Formoterol (n=1) as add-on therapy to 400-565 mcg of beclomethasone or equivalent. Risk of exacerbations requiring systemic corticosteroids was significantly lower with LABA+ICS when compared to LTRA+ICS (RR= 0.83, 95% Confidence Interval (95%CI): 0.71, 0.97): the number needed to treat with LABA compared to LTRA, to prevent one exacerbation over 48 weeks, was 38 (95% CI: 23 to 247). The following outcomes also improved significantly with the addition of LABA compared to LTRA to inhaled steroids (Weighted Mean Difference; 95%CI): morning PEFR (16 L/min; 13 to 18), evening PEFR (12 L/min; 9 to 15), FEV(1) (80 mL; 60 to 100), rescue-free days (9%; 4 to 14), symptom-free days (6%; 2 to 11), rescue beta2-agonists (-0.4 puffs/day; -0.2 to -0.5), quality of life (0.1; 0.05 to 0.2), symptom score (Standard Mean Difference -0.2; -0.1 to -0.3), night awakenings (-0.1/week; -0.06 to -0.2) and patient satisfaction (RR 1.12; 1.07 to 1.16). Risk of withdrawals due to any reason was significantly lower with LABA+ICS compared to LTRA+ICS (Relative Risk 0.84, 95% CI 0.74 to 0.96). Withdrawals due to adverse events or due to poor asthma control, hospitalisation, osteopenia, serious adverse events, overall adverse events, headache or cardiovascular events were not significantly different between the two study groups.

AUTHORS' CONCLUSIONS

In asthmatic adults inadequately controlled on low doses of inhaled steroids, the addition of LABA is superior to LTRA for preventing exacerbations requiring systemic steroids, and for improving lung function, symptoms, and use of rescue beta2-agonists.

Inhaled sodium cromoglycate for asthma in children

BACKGROUND

Sodium cromoglycate has been recommended as maintenance treatment for childhood asthma for many years. Its use has decreased since 1990, when inhaled corticosteroids became popular, but it is still used in many countries.

OBJECTIVES

To determine the efficacy of sodium cromoglycate compared to placebo in the prophylactic treatment of children with asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register (November 2002), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2002), MEDLINE (January 1966 to November 2002), EMBASE (January 1985 to November 2002) and reference lists of articles. We also contacted the pharmaceutical company manufacturing sodium cromoglycate

SELECTION CRITERIA

All double-blind placebo-controlled randomised trials, which addressed the effectiveness of inhaled sodium cromoglycate as maintenance therapy, studying children aged 0 up to 18 years with asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study results were pooled.

MAIN RESULTS

Of 3500 titles retrieved from the literature, 25 papers reporting on 24 studies could be included in the review. The studies were published between 1970 and 1997 and together included 1074 participants. Most were cross-over studies. Few studies provided sufficient information to judge the concealment of allocation. Four studies provided results for the proportion of symptom-free days. Pooling the results did not reveal a statistically significant difference between sodium cromoglycate and placebo. For most of the other outcomes, the results were similar: small effect size and a confidence interval including the point of no difference. The funnel plot showed an under representation of small studies with negative results, suggesting publication bias.

REVIEWER'S CONCLUSIONS

The evidence of the efficacy of sodium cromoglycate over placebo is not proven. Publication bias is likely to have overestimated the beneficial effects of sodium cromoglycate as maintenance therapy in childhood asthma.

Cow's milk protein avoidance and development of childhood wheeze in children with a family history of atopy

BACKGROUND

In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease when breast-feeding is not possible or supplemental feeding is needed. Most infant formulas are based on cow's milk protein. Alternative choices include soya based and hydrolysed cows milk formulas.

OBJECTIVES

To estimate the effect of dietary avoidance of cow's milk protein on the development of asthma or wheeze in children.

SEARCH STRATEGY

The Cochrane database was searched for eligible trials until February 2002. The full text papers of all abstracts identified as RCTs were obtained and reviewed independently by two reviewers.

SELECTION CRITERIA

Randomised controlled trials involving children with a family history of atopy in at least one first degree relative were considered if feeding with cow's milk based standard formula was compared to dietary avoidance of cow's milk protein using soya or other hypoallergenic formula during the initial four months of life or longer.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data independently. A priori defined subgroups were the types of hypoallergenic artificial feed and dietary restrictions on mother and/or child's diet.

MAIN RESULTS

Six trials used hydrolysed formula for at least 4 months in addition to dietary restrictions and in some cases dust-mite reduction measures. The risk of infants experiencing asthma or wheeze during the first year of life was reduced compared to standard cow's milk based formula (Relative Risk =0.40, 95% Confidence Intervals 0.19, 0.85). Feeding soya-based formula as opposed to standard cow's milk formula did not reduce the risk of having asthma or wheeze at any age.

REVIEWER'S CONCLUSIONS

Breast-milk should remain the feed of choice for all babies. In infants with at least one first degree relative with atopy, hydrolysed formula for a minimum of 4 months combined with dietary restrictions and environment measures may reduce the risk of developing asthma or wheeze in the first year of life. There is insufficient evidence to suggest that soya-based milk formula has any benefit.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes agents are currently being studied as alternative first line agents to inhaled corticosteroids in mild to moderate chronic asthma.

OBJECTIVES

To compare the safety and efficacy of anti-leukotriene agents with inhaled glucocorticoids (ICS) and to determine the dose-equivalence of anti-leukotrienes to daily dose of ICS.

SEARCH STRATEGY

Medline (1966 to Jan 2002), Embase (1980 to Jan 2002), and Cinahl (1982 to Jan 2002) were searched and reference lists of review articles and trials. We contacted colleagues and international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

Randomised controlled trials that compared leukotriene antagonists with inhaled corticosteroids during a minimal 30-day intervention period in asthmatic patients aged 2 years and older.

DATA COLLECTION AND ANALYSIS

Two reviewers performed assessments of methodological quality and data extraction independently and blindly. The primary outcome was the rate of exacerbations requiring systemic corticosteroids. Secondary outcomes included lung function, indices of chronic asthma control, adverse effects and withdrawal rates.

MAIN RESULTS

14 trials met the inclusion criteria; 10 were of high methodological quality; 8 are published in full-text. All were in mild-to-moderate chronic asthma, Two included children or adolescents. Trial duration was 4 - 37 weeks. In most trials, daily dose of ICS was 400 mcg of beclomethasone-equivalent. Patients treated with anti-leukotrienes were 60% more likely to suffer an exacerbation requiring systemic steroids [12 trials; Relative Risk 1.61; 95% Confidence Interval (CI) 1.15, 2.25]. Significant differences favouring ICS were noted in most secondary outcomes, eg improvement in FEV1 [7 trials; Weighted Mean Difference 120 ml; 95% CI: 80, 170 ml ]; symptom scores [5 trials: Standardized Mean Difference 0.3; 95% CI 0.2, 0.4]. Other significant benefits of ICS were seen for nocturnal awakenings, rescue medication use, and quality of life. Risk of side effects was not different between groups, but anti-leukotriene therapy was associated with 30% increased risk of "withdrawals for any cause" or "withdrawals due to poor asthma control".

REVIEWER'S CONCLUSIONS

For most asthma outcomes, ICS at 400 mcg/day of beclomethasone-equivalent are more effective than anti-leukotriene agents given in the usual licensed doses. The exact dose-equivalence of anti-leukotriene agents in mcg of ICS remains to be determined.

What is new since the last (1999) Canadian Asthma Consensus Guidelines?

The objective of the present document is to review the impact of new information on the recommendations made in the last (1999) Canadian Asthma Consensus Guidelines. It includes relevant published studies and observations or comments regarding what are considered to be the main issues in asthma management in children and adults in office, emergency department, hospital and clinical settings. Asthma is still insufficiently controlled in a large number of patients, and practice guidelines need to be integrated better with current care. This report re-emphasises the need for the following: objective measures of airflow obstruction to confirm the diagnosis of asthma suggested by the clinical evaluation; identification of contributing factors; and the establishment of a treatment plan to rapidly obtain and maintain optimal asthma control according to specific criteria. Recent publications support the essential role of asthma education and environmental control in asthma management. They further support the role of inhaled corticosteroids as the mainstay of anti-inflammatory therapy of asthma, and of both long acting beta2-agonists and leukotriene antagonists as effective means to improve asthma control when inhaled corticosteroids are insufficient. New developments, such as combination therapy, and recent major trials, such as the Children's Asthma Management Project (CAMP) study, are discussed.

Efficacy of fluticasone nasal spray for pediatric obstructive sleep apnea

OBJECTIVE

We tested the hypothesis that a 6-week course of a nasal glucocorticoid spray would decrease the severity of obstructive sleep apnea in children with adenotonsillar hypertrophy.

STUDY DESIGN

We conducted a randomized, triple-blind, placebocontrolled, parallel-group trial of nasal fluticasone propionate versus placebo in 25 children aged 1 to 10 years with obstructive sleep apnea proven on polysomnography. The primary outcome was the change from baseline in the frequency of mixed and obstructive apneas and hypopneas.

RESULTS

Thirteen children received fluticasone, and 12 received placebo. The mixed/obstructive apnea/hypopnea index decreased from 10.7 +/- 2.6 (SE) to 5.8 +/- 2.2 in the fluticasone group but increased from 10.9 +/- 2.3 to 13.1 +/- 3.6 in the placebo group, P =.04. The mixed/obstructive apnea/hypopnea index decreased in 12 of 13 subjects treated with fluticasone versus 6 of 12 treated with placebo, P =.03. The frequencies of hemoglobin desaturation and respiratory movement/arousals also decreased more in the fluticasone group. Changes from baseline in tonsillar size, adenoidal size, and symptom score were not significantly different between groups.

CONCLUSION

Nasal fluticasone decreased the frequency of mixed and obstructive apneas and hypopneas, suggesting that topical corticosteroids may be helpful in ameliorating pediatric obstructive sleep apnea.

Interventions for educating children who have attended the emergency room for asthma

BACKGROUND

Asthma is one of the most common reasons for paediatric admissions to hospital, with substantial cost to the community. There is some evidence to suggest that many hospital admissions could be prevented with effective education about asthma and its management.

OBJECTIVES

To conduct a systematic review of the literature in order to identify whether asthma education leads to improved health outcomes in children who have attended the emergency department for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register, including Medline, Embase, and Cinahl databases, and reference lists of trials and review articles.

SELECTION CRITERIA

Randomised controlled trials or controlled clinical trials of asthma education for children who had attended the emergency department for asthma, with or without hospitalisation, within the previous 12 months.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Eight trials involving 1407 patients were included, in all the education was provided by nurses or researchers. Compared to control (usual care or lower intensity education) education did not reduce subsequent emergency department (ED) visits [4 trials; relative risk (RR)= 0.87, 95% confidence interval (CI) 0.37 to 2.08], hospital admissions [5 trials; RR=0.74, 95% CI 0.38 to 1.46] and unscheduled doctor visits [5 trials; RR= 0.74, 95% CI 0.49 to 1.12). Each analysis showed evidence of heterogeneity among the studies (P<0.01). Subgroup analyses by the overall difference in scale of intervention between treatment and control groups (comprehensive programme versus information only) or the timing of the intervention/recruitment (early versus delayed) gave similar results to the main analysis and still revealed significant heterogeneity between trials.

REVIEWER'S CONCLUSIONS

On the basis of the published trials, there is no firm evidence to support the use of asthma education for children who have attended the emergency department for asthma as a means of reducing subsequent ED visits, hospital admissions or unscheduled doctor visits. Some trials appeared to show clear evidence of benefit, but reasons for differences between these and the negative studies is not clear. More research is required

Intravenous aminophylline for acute severe asthma in children over 2 years using inhaled bronchodilators

BACKGROUND

Intravenous aminophylline was the bronchodilator of choice for many years until supplanted by more effective bronchodilators in the treatment of acute paediatric asthma. Recently there has been renewed interest in this therapy for children with acute severe asthma.

OBJECTIVES

To determine whether addition of intravenous aminophylline produces a beneficial effect in children with acute severe asthma receiving oxygen, maximised inhaled bronchodilators and oral/intravenous glucocorticoids.

SEARCH STRATEGY

The Cochrane Airways Group register of trials (based on MEDLINE, EMBASE, CINAHL and hand searched respiratory journals) and reference lists of relevant articles were used to identify relevant studies. The latest search was carried out in October 2000.

SELECTION CRITERIA

Only randomised-controlled trials comparing intravenous aminophylline with placebo in children treated with inhaled bronchodilators and systemic glucocorticoids for acute asthma were considered for this review.

DATA COLLECTION AND ANALYSIS

Full text of 35 trials were anonymized for author, date and publication and two blinded independent reviewers selected eligible studies for inclusion. Disagreement was resolved through consensus. Seven trials met the inclusion criteria. Attempts were made to contact authors to verify accuracy. Results were reported as weighted mean differences (WMD) or relative risk (RR) with 95% confidential intervals (CI).

MAIN RESULTS

Patients in these trials were predominantly school-aged children hospitalised for acute severe asthma with a baseline FEV1 at 35-40% of predicted and/or a baseline Pulmonary Index of 6-7. Aminophylline significantly improved percentage predicted FEV1 by 6 - 8 hours (WMD 8.4%; 95% CI: 0.82, 15.92%). The effect was maintained for 24 hours. Improvements were also seen in symptom scores at 6-8 hours (WMD= -0.71; 95% CI: -0.82,-0.60). There was no reduction in hospital stay or in number of nebulisers required. Vomiting was more likely with aminophylline therapy (Relative Risk = 3.69; 95% CI: 2.15, 6.33).

REVIEWER'S CONCLUSIONS

Addition of intravenous aminophylline should be considered early in the treatment of children hospitalised with acute severe asthma with sub optimal response to the initial inhaled bronchodilator therapy. Although the improvement is sustained for 24 hours, there is no apparent reduction in length of hospital stay or number of inhaled beta2-agonists nebulisations. Treatment with aminophylline is associated with an increased risk of vomiting.

The Preschool Respiratory Assessment Measure (PRAM): a responsive index of acute asthma severity

OBJECTIVE

To elaborate and validate a Preschool Respiratory Assessment Measure (PRAM) that would accurately reflect the severity of airway obstruction and the response to treatment in young patients with asthma.

STUDY DESIGN

A prospective cohort study was performed in 217 children aged 3 to 6 years who presented to a pediatric emergency department with acute asthma. Respiratory resistance measured by forced oscillation served as a gold standard. Children were randomized to either the test group, in which multivariate analyses were performed to elaborate the PRAM, or the validation group, in which the characteristics of the PRAM were tested.

RESULTS

For the test group (N = 145), the best multivariate model contained 5 variables: wheezing, air entry, contraction of scalenes, suprasternal retraction, and oxygen saturation. In the validation group (N = 72), the PRAM correlated substantially with the change in resistance (r = 0.58) but modestly with the % predicted resistance measured before (r = 0.22) and after bronchodilation (r = 0.36). A change of 3 (95% CI: 2.2, 3.0) indicated a clinically important change.

CONCLUSIONS

PRAM appears to be a responsive but moderately discriminative tool for assessing acute asthma severity. This measure, designed for preschool-aged children, has been validated against a concurrent measure of lung function.

Nocturnal pulse oximetry as an abbreviated testing modality for pediatric obstructive sleep apnea

OBJECTIVE

To determine the utility of pulse oximetry for diagnosis of obstructive sleep apnea (OSA) in children.

METHODS

We performed a cross-sectional study of 349 patients referred to a pediatric sleep laboratory for possible OSA. A mixed/obstructive apnea/hypopnea index (MOAHI) greater than or equal to 1 on nocturnal polysomnography (PSG) defined OSA. A sleep laboratory physician read nocturnal oximetry trend and event graphs, blinded to clinical and polysomnographic results. Likelihood ratios were used to determine the change in probability of having OSA before and after oximetry results were known.

RESULTS

Of 349 patients, 210 (60%) had OSA as defined polysomnographically. Oximetry trend graphs were classified as positive for OSA in 93 and negative or inconclusive in 256 patients. Of the 93 oximetry results read as positive, PSG confirmed OSA in 90 patients. A positive oximetry trend graph had a likelihood ratio of 19.4, increasing the probability of having OSA from 60% to 97%. The median MOAHI of children with a positive oximetry result was 16.4 (7.5, 30.2). The 3 false-positive oximetry results were all in the subgroup of 92 children who had diagnoses other than adenotonsillar hypertrophy that might have affected breathing during sleep. A negative or inconclusive oximetry result had a likelihood ratio of.58, decreasing the probability of having OSA from 60% to 47%. Interobserver reliability for oximetry readings was very good to excellent (kappa =.80).

CONCLUSIONS

In the setting of a child suspected of having OSA, a positive nocturnal oximetry trend graph has at least a 97% positive predictive value. Oximetry could: 1) be the definitive diagnostic test for straightforward OSA attributable to adenotonsillar hypertrophy in children older than 12 months of age, or 2) quickly and inexpensively identify children with a history suggesting sleep-disordered breathing who would require PSG to elucidate the type and severity. A negative oximetry result cannot be used to rule out OSA.

Combined inhaled anticholinergic agents and beta-2-agonists for initial treatment of acute asthma in children

BACKGROUND

Anti-cholinergic agents and beta2-agonist drugs are both bronchodilators used to reverse acute bronchospasm in children with asthma. These drugs have different modes of action, so may have complementary or additive effects.

OBJECTIVES

The objective of this review was to assess the effects of adding inhaled anti-cholinergics to beta2-agonists in acute paediatric asthma.

SEARCH STRATEGY

We searched Medline (1966 to 1996), Embase (1980 to 1995), Cinahl (1982 to 1995) and reference lists of studies. We also contacted drug manufacturers and researchers.

SELECTION CRITERIA

Randomised trials comparing the combination of inhaled anti-cholinergics and beta2-agonists with beta2-agonists alone in children aged 18 months to 17 years with acute asthma.

DATA COLLECTION AND ANALYSIS

Assessments of trial quality and data extraction were done by two reviewers independently.

MAIN RESULTS

Ten trials involving a total of 836 children were included. Most trials were of high quality. When only one dose of anti-cholinergic inhalation was added to beta2-agonist therapy, there was an improvement in forced expiratory volume in one second after 60 minutes with combination therapy (weighted mean difference 16.1%, 95% confidence interval 5.5 to 26. 7% reduction). There was no reduction in hospital admission (odds ratio 0.80, 95% confidence interval 0.35 to 1.82, using a random effects model). For multiple doses in children with severe asthma, there was a reduction in forced expiratory volume in 1 second (weighted mean difference 9.8% predicted, 95% confidence interval 6. 5 to 13.1% predicted). There may also be a reduction in hospital admission (odds ratio 0.62, 95% confidence interval 0.38 to 0.99). Eleven children would need to be given multiple doses of anti-cholinergics in combination with beta2-agonists to avoid one hospital admission compared to children given beta2-agonists alone.

REVIEWER'S CONCLUSIONS

In children with acute asthma, the addition of multiple doses of anti-cholinergics to inhaled beta2-agonists appears to improve lung function modestly and may decrease hospital admission. There is no associated increase in adverse effects. Single doses of anti-cholinergics may improve lung function in children with severe asthma, but do not appear to reduce hospital admissions.

Early emergency department treatment of acute asthma with systemic corticosteroids

BACKGROUND

The airway edema and secretions associated with acute asthma are most effectively treated with anti-inflammatories such as corticosteroids delivered by inhaled, oral, intravenous or intra-muscular routes. There is an unresolved debate about the use of systemic corticorticoids in the early treatment of acute asthma for emergency department patients.

OBJECTIVES

To determine the benefit of treating patients with acute asthma with systemic corticosteroids within an hour of presenting to the emergency department (ED).

SEARCH STRATEGY

Randomised controlled trials were identified from the Cochrane Airways Group Asthma Register. Primary authors and content experts were contacted to identify eligible studies. Bibliographies from included studies and known reviews were searched.

SELECTION CRITERIA

Only randomised controlled trials (RCTs) or quasi-randomised trials were eligible for inclusion. Studies were included if patients presenting to the ED with acute asthma were treated with IV/IM or oral corticosteroids (CS) vs. placebo within 1 hour of arrival and either admission rate or pulmonary function results were reported.

DATA COLLECTION AND ANALYSIS

Trial selection, data extraction and quality assessment were carried out independently by two reviewers, and confirmed with corresponding authors.

MAIN RESULTS

Twelve studies involving 863 patients (435 corticosteroids; 428 placebo) were included. Early use of CS for acute asthma in the ED significantly reduced admission rates (N = 11; pooled OR: 0.40, 95% CI: 0.21 to 0.78). This would correspond with a number needed to treat of 8 (95% CI: 5 to 21). This benefit was more pronounced for those not receiving systemic CS prior to ED presentation (N = 7; OR: 0.37, 95% CI: 0.19 to 0.70) and those with more severe asthma (N = 7; OR: 0.35, 95% CI: 0.21 to 0. 59). Oral CS therapy in children was particularly effective (N = 3; OR: 0.24, 95% CI: 0.11 to 0.53); no trials in adults used the oral route. Side effects were not significantly different between corticosteroid treatments and placebo.

REVIEWER'S CONCLUSIONS

Use of corticosteroids within 1 hour of presentation to an ED significantly reduces the need for hospital admission in patients with acute asthma. Benefits appear greatest in patients with more severe asthma, and those not currently receiving steroids. Children appear to respond well to oral steroids.

Corticosteroids for preventing relapse following acute exacerbations of asthma

BACKGROUND

Acute asthma is responsible for many emergency department visits annually. Between 12-16% will relapse to require additional interventions within two weeks of ED discharge. Treatment of acute asthma is based on rapid reversal of bronchospasm and reducing airway inflammation and this review examines the evidence for using systemic corticosteroids to improve outcomes after discharge from the ED.

OBJECTIVES

To determine the benefit of corticosteroids (oral, intramuscular, or intravenous) for the treatment of asthmatic patients discharged from an acute care setting (i.e. usually the emergency department) after assessment and treatment of an acute asthmatic exacerbation.

SEARCH STRATEGY

The Cochrane Airways Group "Asthma and Wheez* RCT" register was searched using the terms: a) Asthma OR Wheez* b) Glucocorticoid OR Steroid* AND c) Exacerbat* OR Relapse* OR Emerg*. In addition, authors of all included studies were contacted to determine if unpublished studies which met the inclusion criteria were available. Bibliographies from included studies, known reviews and texts were also searched for additional citations.

SELECTION CRITERIA

Only randomized controlled trials were eligible for selection. Studies were included in this review if they dealt with the outpatient treatment of asthmatic exacerbations using glucocorticoids at discharge and reported either relapse rate or PFTs. Two independent reviewers first identified potentially relevant studies and then selected articles for inclusion. Methodological quality was assessed independently by two reviewers. Agreement was assessed using kappa (k) statistics.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers; authors were contacted to verify the extracted data and clarify missing information. When author contact was unsuccessful, missing data were estimated from graphs where possible. Sensitivity, sub-group and overall analyses were performed using the Cochrane Review Manager.

MAIN RESULTS

A search that yielded 229 references identified 169 (73%) original publications. Reviewers identified 8 studies for potential inclusion (k =0.76); 18 references were added by searching publication reference lists and contact with authors. Of these 26 articles, a total of 7 were included in the overview. Two studies used intramuscular corticosteroids, five studies used oral corticosteroids. Significantly fewer patients in the corticosteroid group relapsed to receive additional care in the first week (odds ratio (OR) 0.35; 95% confidence interval (CI): 0.17, 0.73). This favourable effect was maintained over the first 21 days (OR 0.33; 95% CI: 0.13, 0.82). Patients receiving corticosteroids had less need for beta-agonists (weighted mean difference (WMD) -3.3 activations/day; 95% CI: -5.5, -1.0). Changes in pulmonary function tests (SMD 0.045; 95% CI: -0.47, 0.56) and side effects (SMD 0.03; 95% CI : -0.38, 0.44) in the first 7-10 days, while rarely reported, showed no differences between the treatment groups. Statistically significant heterogeneity was identified for the side effect results; all other outcomes were homogeneous. It appears that IM corticosteroids are similarly efficacious to a 7-10 day tapering course of oral agents. From these results, as few as 13 patients need to be treated to prevent relapse to additional care after an exacerbation of asthma.

REVIEWER'S CONCLUSIONS

A short course of corticosteroids following assessment for an acute exacerbation of asthma significantly reduces the number of relapses to additional care and decreases beta-agonist use without an apparent increase in side effects. Intramuscular corticosteroids appear as effective as oral agents.

What do nurses and residents know about childhood asthma?

OBJECTIVES

To assess residents' and pediatric nurses' basic knowledge of childhood asthma and to identify areas needing educational reinforcement.

DESIGN

Survey using a validated self-administered questionnaire containing 25 true-false and six short open-ended questions.

PARTICIPANTS

Pediatric residents and family medicine residents who were on rotation at a tertiary care pediatric hospital over a six-month period, and pediatric nurses on duty in the emergency department, on the wards and on the pediatric intensive care unit over a month period.

RESULTS

The participation rate was 80% (28 of 35) of pediatric residents, 89% (33 of 37) of family medicine residents, and 50% (81 of 163) of pediatric nurses. The mean score (+/- standard deviation) on the 31-point questionnaire was 27.7+/-1.8 for pediatric residents, 25.5+/-3.6 for family medicine residents, and 22.3+/-3.8 for pediatric nurses (ANOVA, P<0.001). Most (at least 75%) participants correctly identified bronchospasm and airway inflammation as two potential mechanisms of asthma and were able to list three routinely used drugs to treat exacerbations. However, 32% of pediatric residents, 12% of family medicine residents and 72% of pediatric nurses failed to identify all three main symptoms of asthma (wheezing, cough, dyspnea). Although most participants recognized that children with frequent exacerbations should receive prophylactic therapy, 25% of pediatric residents, 52% of family medicine residents and 81% of pediatric nurses were unable to name at least two preventive asthma medications. More than 50% of participants could not name two drugs used in the prevention of exercise-induced asthma.

CONCLUSIONS

Residents and nurses had adequate basic knowledge of the treatment of acute exacerbations. However, most individuals needed reinforcement in preventive asthma therapy and daily management.

Clinical decisionmaking based on venous versus capillary blood gas values in the well-perfused child

STUDY OBJECTIVE

In children aged 1 month to 18 years, we sought to examine the correlation between venous and arterialized capillary blood gas values, and to determine whether the source of blood sample influenced the interpretation of the acid-base status and clinical management.

METHODS

In a cross-sectional study, venous and capillary blood gas values were simultaneously obtained in acutely ill well-perfused patients treated in a pediatric emergency department. Intraclass correlation coefficients for capillary and venous measured gas values were calculated. Crude agreement and intraobserver concordance were calculated for responses of 2 intensivists to the interpretation and clinical management questions, based on capillary and venous gas results.

RESULTS

Intraclass correlation coefficients for 78 capillary and venous paired measured gas values were.92 (pH), .80 (PCO 2 ), and .67 (PO 2 ). The alpha of concordance values between capillary and venous blood gas values, with 95% confidence intervals (CIs) were as follows, respectively, for physician A and B: interpretation, .61 (.47 to .73) and .48 (.41 to .55); need for bicarbonate,.85 (.73 to.97) and.80 (.72 to.88); and need for intubation .73 (.64 to .82), and .83 (.75 to .91).

CONCLUSION

In the well-perfused patient, we believe that venous samples are an acceptable alternative to capillary blood samples for determination of blood gas values and for making clinical management decisions.

Should inhaled anticholinergics be added to beta2 agonists for treating acute childhood and adolescent asthma? A systematic review

OBJECTIVES

To estimate the therapeutic and adverse effects of addition of inhaled anticholinergics to beta2 agonists in acute asthma in children and adolescents.

DESIGN

Systematic review of randomised controlled trials of children and adolescents taking beta2 agonists for acute asthma with or without the addition of inhaled anticholinergics.

MAIN OUTCOME MEASURES

Hospital admission, pulmonary function tests, number of nebulised treatments, relapse, and adverse effects.

RESULTS

Of 37 identified trials, 10 were relevant and six of these were of high quality. The addition of a single dose of anticholinergic to beta2 agonist did not reduce hospital admission (relative risk 0.93, 95% confidence interval 0.65 to 1.32). However, significant group differences in lung function supporting the combination treatment were observed 60 minutes (standardised mean difference -0.57, -0.93 to -0.21) and 120 minutes (-0.53, -0.90 to -0.17) after the dose of anticholinergic. In contrast, the addition of multiple doses of anticholinergics to beta2 agonists, mainly in children and adolescents with severe exacerbations, reduced the risk of hospital admission by 30% (relative risk 0.72, 0.53 to 0.99). Eleven (95% confidence interval 5 to 250) children would need to be treated to avoid one admission. A parallel improvement in lung function (standardised mean difference -0.66, -0.95 to -0.37) was noted 60 minutes after the last combined inhalation. In the single study where anticholinergics were systematically added to every beta2 agonist inhalation, irrespective of asthma severity, no group differences were observed for the few available outcomes. There was no increase in the amount of nausea, vomiting, or tremor in patients treated with anticholinergics.

CONCLUSIONS

Adding multiple doses of anticholinergics to beta2 agonists seems safe, improves lung function, and may avoid hospital admission in 1 of 11 such treated patients. Although multiple doses should be preferred to single doses of anticholinergics, the available evidence only supports their use in school aged children and adolescents with severe asthma exacerbation.

Randomized controlled trial of ipratropium bromide and frequent low doses of salbutamol in the management of mild and moderate acute pediatric asthma

OBJECTIVES

To compare the effectiveness and safety of alternative nebulized drug protocols in children with mild or moderate asthma exacerbations.

METHODS

We conducted a blinded, randomized, controlled trial with a 2 x 2 factorial design. Two interventions, nebulized salbutamol in frequent low doses (0.075 mg/kg every 30 minutes) and the addition of ipratropium bromide (250 micrograms), were compared with salbutamol in hourly high doses (0.15 mg/kg every 60 minutes) in children with mild or moderate acute asthma. The primary end point was the improvement in respiratory resistance. Secondary end points included oxygen saturation, corticosteroid use, patient disposition, and relapse status.

RESULTS

A total of 298 participants aged 3 to 17 years were studied, and 15% were admitted to the hospital; 14% of the children had relapses. No increased bronchodilation was associated with frequent low doses versus hourly high doses of salbutamol (RR = 0.9 [95% confidence interval 0.7, 1.3]) or the addition of ipratropium bromide versus placebo (RR = 1.0 [0.8, 1.3]). No group differences were observed in secondary end points. Salbutamol in frequent low doses was associated with increased vomiting (RR = 2.5 [1.1, 6.0]).

CONCLUSION

Our results do not support the use of frequent low doses of nebulized salbutamol or the addition of ipratropium bromide compared with hourly high doses of salbutamol in children with mild or moderate asthma.

Respiratory resistance in the emergency department: a reproducible and responsive measure of asthma severity

OBJECTIVES

To determine, in preschool children with an acute asthma exacerbation, the responsiveness to change of respiratory resistance measurements obtained by the forced oscillation (Rfo) technique, and to identify the magnitude of change indicative of airway obstruction reversibility.

DESIGN/SETTING

A prospective observational study of 114 children, aged 3 to 17 years, untrained in the Rfo technique and treated for acute asthma in a tertiary-care pediatric emergency department (ED).

MEASUREMENTS

A physical examination followed by three measurements of respiratory resistance by forced oscillation were obtained at 8 Hz (Rfo8) and at 16 Hz (Rfo16). In cooperative children, routine spirometry that included FEV1 was also performed on the Custo Vit R (Custo Med; Munich, Germany). All measurements were obtained twice during the course of the ED treatment, before and after treatment with nebulized bronchodilators.

RESULTS

The Rfo8 and Rfo16 measurements were highly reproducible (reproducibility coefficients >0.85). Both the Rfo8 and Rfo16 were at least as responsive to change (responsiveness coefficients of 2.3 and 1.2, respectively) as was FEV1 (2.0) and the four clinical signs most sensitive to change (0.6 to 1.0). A 19% change in Rfo8 was suggestive of significant reversibility.

CONCLUSIONS

In the assessment of children aged > or =3 years with acute asthma exacerbation, the respiratory resistance measurements are highly reproducible and responsive to change, particularly when obtained at 8 Hz. A 19% change from baseline Rfo8 is suggestive of reversibility. This technique appears to be an attractive alternative in the evaluation of children who are too young or too sick to perform spirometry reproducibly.

Pediatric reference values for respiratory resistance measured by forced oscillation

OBJECTIVES

To determine, in North American children, reference values for respiratory resistance measurements by the forced oscillation (Rfo) technique and to examine whether sitting height, as index of truncal length, is a better determinant of resistance, less influenced by race and gender, than standing height.

DESIGN/SETTING

A prospective cross-sectional study of healthy nonobese children, carefully selected for absence of atopy, exposure to tobacco smoke, and recent upper respiratory tract infection.

MEASUREMENTS

Three measurements of respiratory resistance by forced oscillation were obtained at the fixed frequencies of 8 Hz (Rfo8), 12 Hz (Rfo12), and at 16 Hz (Rfo16) using the Custo Vit R (Custo Med GMBH; Munich, Germany). In cooperative children, routine spirometry (FEV1, FVC, and peak expiratory flow rate [PEFR]) was also performed.

RESULTS

We recruited 217 healthy children aged 3 to 17 years. Reproducible measurements of Rfo8 were obtained for 206 children, Rfo12 for 197 children, and Rfo16 for 209 children. Normal FEV1, FVC, and PEFR values were documented in all 69 subjects who were able to reproducibly cooperate with spirometry. Multiple linear regression identified measurements of either sitting or standing height as the best, and equally strong, determinants of respiratory resistance at all three frequencies. Gender and race were not important factors once either sitting or standing height measurement was considered. Our regression equations at 8 Hz are comparable to published reference values obtained at fixed frequencies of 6, 8, and 10 Hz using other instruments. However, in comparison to our results, prior values tended to underestimate resistance in the shortest children or to overestimate it in the tallest ones. Our regression equation for Rfo12 is similar to the only previously published one, while no reference values at 16 Hz were available for comparison.

CONCLUSIONS

Height is the best predictor for total respiratory resistance at 8, 12, and 16 Hz in children aged > or = 3 years. Use of sitting height does not appear to be a stronger determinant of resistance than standing height.

Sleep-disordered breathing in children with myelomeningocele

BACKGROUND

Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined.

METHODS

A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry.

RESULTS

A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%.

CONCLUSIONS

The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.

Do systemic corticosteroids effectively treat obstructive sleep apnea secondary to adenotonsillar hypertrophy?

To determine if pediatric obstructive sleep apnea syndrome (OSAS) caused by adenotonsillar hypertrophy (ATH) could be treated by a short course of systemic corticosteroids, we conducted an open-label pilot study in which standardized assessments of symptomatology, OSAS severity, and adenotonsillar size were performed before and after a 5-day course of oral prednisone, 1.1+/-0.1 (+/-SE) mg/kg per day. Outcome measures included symptom severity, adenotonsillar size, and polysomnographic measures of OSAS. Selection criteria included age from 1 to 12 years, ATH, symptomatology suggesting OSAS, an apnea/hypopnea index (AHI) > or = 3/hour, and intent to perform adenotonsillectomy. Only one of nine children showed enough improvement to avoid adenotonsillectomy. Symptomatology did not improve after corticosteroid treatment but did after removal of tonsils and adenoids. Polysomnographic indices of OSAS severity did not improve after corticosteroid treatment. After corticosteroids, tonsillar size decreased in only two patients, adenoidal size was only marginally reduced, and the size of the nasopharyngeal airway was not significantly increased. These results suggest that a short course of prednisone is ineffective in treating pediatric OSAS caused by ATH.

Measurement of respiratory resistance in the emergency department: feasibility in young children with acute asthma

OBJECTIVES

To assess, in acutely ill asthmatic children, the feasibility of obtaining reproducible measurements of two independent lung function tests, namely spirometry and respiratory resistance, using the forced oscillation technique (Rfo).

DESIGN/SETTING

A prospective observational study of 150 previously untrained children, aged 2 to 17 years, treated for acute asthma in a tertiary-care pediatric emergency department.

MEASUREMENTS

Following a standardized physical examination, three measurements of respiratory resistance by forced oscillation were attempted at 8 Hz (Rfo8) and at 16 Hz (Rfo16), followed by spirometry, all using the same instrument (Custo Vit R; Custo Med; Munich, Germany).

RESULTS

On the initial assessment, 98 (65%) children, aged 2 to 17 years, were able to reproducibly perform the Rfo8 measurement, 77 (51%) were able to reproducibly perform the Rfo16 measurement, while only 65 (43%) subjects managed to reliably perform spirometry. A notable proportion of preschool-aged children cooperated with the Rfo8 technique: 19% of 3-year-olds, 40% of 4-year-olds, and 83% of 5-year-olds. The superior success rate with Rfo8 as compared with spirometry was seen in all age groups but was most striking both in preschoolers (relative risk [RR]=10.5; 95% confidence interval [CI], 8.0 to 13.8) and in children aged 6 to 9 years (RR= 1.28; 95% CI, 1.18 to 1.39). Rfo8 values correlated significantly with clinical markers of asthma severity such as respiratory rate (r=0.38) and heart rate (r=0.23) as well as with FEV1 values (r2=0.73).

CONCLUSIONS

This study demonstrates the feasibility of obtaining reproducible measurements of respiratory resistance in a notable proportion of untrained, acutely ill, asthmatic children. The forced oscillation technique appears as an attractive alternative to objectively assess lung function in children too young or too ill to cooperate with spirometry.

Cardiorespiratory sleep studies for children can often be performed in the home

We developed a portable recording system, suitable for unattended use in a patient's home, that quantitates the essential diagnostic elements of pediatric obstructive sleep apnea syndrome (OSAS): obstructive, mixed and central apneas and hyponeas; hemoglobin saturation, sleep vs. wakefulness; body and head positions; snoring: and sleep disturbance. The present paper reviews validation studies and summarizes two recent studies that demonstrate the unique advantages of performing clinical and research cardiorespiratory sleep studies in the child's home. Development of inexpensive, portable records that integrate audiovisual and physiologic information will make such home recordings more widely available.

Can sleep and wakefulness be distinguished in children by cardiorespiratory and videotape recordings?

Polysomnography, including EEG recording, is the standard method to diagnose obstructive sleep apnea (OSA) in children and adults. Diagnosis of OSA would be considerably simplified if it was shown that sleep could be distinguished from wakefulness without EEG recordings. Therefore, we compared sleep/wakefulness classification using a simplified cardiorespiratory-video (CRV) method with standard polysomnography in 20 children undergoing in-hospital evaluation for OSA. The channels for the simplified montage were chosen because they (1) were suitable for unattended, home recordings, (2) allowed the diagnosis of apneas, hypopneas, desaturation, and movement/arousals, and (3) did not require attachment to the head or face that might disturb the childs sleep. Sleep staging by the two methods was blinded to results of the other method. We evaluated 21,832 30-s epochs--1,092+/-111 (SD) per child. Across 20 subjects, 79.7+/-7.1% of the epochs were sleep. The simplified montage agreed with polysomnographic classification of sleep/wakefulness for 93.8+/-2.5% of the epochs. Of all sleep epochs, 97.7 (96.4, 98.1%) median (interquartile range), were correctly classified; sleep predictive value of the CRV method was 95.2+/-2.8%. Of all epochs classified as wakefulness by polysomnography, 80.1+/-12.8% were correctly classified by the CRV method. The wakeful predictive value was 88.7+/-2.6%. Kappa values averaged 0.8+/-0.1, indicating that agreement between the CRV method and polysomnography did not occur by chance and that the level of agreement was excellent. Thus, sleep can be distinguished from wakefulness in children being evaluated for OSA using a combination of cardiorespiratory and videotape recordings. These results suggest that the CRV method would be useful in a pediatric laboratory setting where EEG recordings are not always possible. They also suggest that overnight, unattended CRV recordings in a childs own home could correctly distinguish sleep from wakefulness.

Pulse oximetry: accuracy of methods of interpreting graphic summaries

Although pulse oximetry has been used to determine the frequency and extent of hemoglobin desaturation during sleep, movement artifact can result in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pulmonologists' and technicians' interpretations of graphic displays of desaturation events, derived an objective method for interpreting such events, and validated the method on an independent data set. Eighty-seven randomly selected desaturation events were classified as valid (58) or artifactual (29) based on cardiorespiratory recordings (gold standard) that included pulse waveform and respiratory inductive plethysmography signals. Using oximetry recordings (test method), nine pediatric pulmonologists and three respiratory technicians ("readers") averaged 50 +/- 11% (SD) accuracy for event classification. A single variable, the pulse amplitude modulation range (PAMR) prior to desaturation, performed better in discriminating valid from artifactual events with 76% accuracy (P < 0.05). Following a seminar on oximetry and the use of the PAMR method, the readers' accuracy increased to 73 +/- 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% artifactual), the PAMR method of assessing oximetry graphs yielded 82% accuracy; transcutaneous oxygen tension records confirmed a drop in oxygenation during 49 of 54 (89%) valid desaturation events. In conclusion, the most accurate method (91%) of assessing desaturation events requires recording of the pulse and respiratory waveforms. However, a practical, easy-to-use method of interpreting pulse oximetry recordings achieved 76-82% accuracy, which constitutes a significant improvement from previous subjective interpretations.

Home testing for pediatric obstructive sleep apnea syndrome secondary to adenotonsillar hypertrophy

The objective of this study was to determine the accuracy and practicality of home testing for pediatric obstructive sleep apnea syndrome (OSAS) secondary to adenotonsillar hypertrophy. Twenty-one children aged 2-12 years and referred for possible OSAS were studied twice, once at home and once in the sleep laboratory. The home test consisted of two parts: 1) a cardiorespiratory recording of saturation (SaO2), pulse rate, pulse waveform, electrocardiogram, and respiratory inductive plethysmography; and 2) an 8-hour videotape recording of the sleeping child. In the laboratory, standard nocturnal polysomnography including electroencephalography was performed. Experiences with another 62 children who underwent home testing alone were also reviewed and are reported. At home, saturation, respiratory, and video data were obtained 96.4 +/- 13.3% (mean +/- SD) 99.4 +/- 1.6%, and 90.0 +/- 78% of the time, respectively. The sleep efficiency was greater at home than in the laboratory, 91.1 +/- 3.9% vs. 86.1 +/- 7.2%, with a mean difference of 5.0% (P < 0.01). The median environmentally induced movement/arousal index was lower in the home than in the laboratory, 0.0 (inter-quartile range, 0.0-0.3 vs. 2.4/hr (inter-quartile range 1.2-4.2), with a median difference of 2.4/h (P < 0.001). Study duration, apnea/hypopnea index, desaturation index, respiratory and spontaneous movement/arousal indices, and oxygen saturation during sleep were similar for home and laboratory studies. Although neither sleep state nor PCO2 (transcutaneous or end-tidal) was measured in the home, this information would have modified patient management in, at most, one case. In the second group of 62 children, exclusively studied at home, all studies were successfully recorded despite a wide range of sleep efficiencies, apnea/hypopnea indices, and desaturation indices. We conclude that home testing, using a simplified cardiorespiratory montage plus video recording, is accurate and of practical use in the routine evaluation of OSAS in patients with adenotonsillar hypertrophy.

Movement/arousals. Description, classification, and relationship to sleep apnea in children

Movement/arousal has been described as a characteristic of adult obstructive sleep apnea syndrome (OSAS), but opinions differ as to whether or not OSAS in children increases the frequency of movement/arousal. The problem that we decided to address was the lack of a comprehensive definition and characterization of movement/arousals in children. We therefore quantified and classified movement/arousals during nocturnal polysomnography in 15 children 5.2 +/- 2.7 SD yr of age being evaluated for OSAS. Movement/arousals were defined by modifying the standard criteria for scoring arousals in adults. Median respiratory disturbance index was 4.4/h, with a range of 1 to 28/h. Videotape review was required to adequately distinguish technician-induced from spontaneous movement/arousals. Although movement/arousal durations varied from 1 s to prolonged awakenings, a high frequency of brief, 1- to 3-s movement/arousals occurred in all classification categories: respiratory, 44%; technician-induced, 33%; spontaneous, 36%. When comparing a 16-channel PSG montage with that of a seven-channel cardiorespiratory montage, we found that 84% of all movement/arousals could be detected using the abbreviated montage. In conclusion, we propose a simple classification system that distinguishes three types of movement/arousals: respiratory, technician-induced, and spontaneous. Our results further suggest that a simple montage using cardiorespiratory channels and videotaping would be suitable for home study and sensitive for identifying movement/arousals.

Relapse following emergency treatment for acute asthma: can it be predicted or prevented?

We prospectively followed 314 children discharged from a children's hospital emergency department (ED) following an asthma attack, to identify risk, factors for relapse, i.e. a second ED visit for asthma within the next 10 days. Parents were surveyed concerning their child's past medical history, drugs received prior to the index visit, triggering factors, physician availability, parental anxiety, and sociodemographic variables. Data on severity of the attack, emergency treatment, response to treatment and drugs prescribed on discharge were extracted from the medical record. Ninety-six of the 314 children (31%) relapsed, most (68%) within 24 hours. Using multiple logistic regression, a predictive model was developed on 211 patients ("test sample"). The best model contained two variables: (1) the number of ED visits for acute asthma in the previous year (odds ratio [OR] = 2.4 for 4 or more vs fewer visits, 95% CI = 1.3-4.4) and (2) the intake of an oral short-acting theophylline preparation during the course of the acute treatment (OR = 0.4, 95% CI = 0.2-0.7). The sensitivity, specificity and positive predictive values of this model for predicting relapse were 73, 53, and 40%, respectively. When applied to a second randomly selected "validation sample" of 103 children, sensitivity was 73%, specificity 50%, and PPV 41%, thus indicating the stability of the model. The model identifies the number of ED visits in the previous year as an important risk factor for relapse. It also suggests that oral short-acting theophylline may still have a role in the treatment of patients in whom the contribution of inflammation to airway obstruction is minimal.