Severe asthma assessment, management and the organisation of care in Australia and New Zealand: expert forum roundtable meetings

Severe asthma imposes a significant burden on individuals, families and the healthcare system. Treatment is complex, due to disease heterogeneity, comorbidities and complexity in care pathways. New approaches and treatments improve health outcomes for people with severe asthma. However, emerging multidimensional and targeted treatment strategies require a reorganisation of asthma care. Consensus is required on how reorganisation should occur and what areas require further research. The Centre of Excellence in Severe Asthma convened three forums between 2015 and 2018, hosting experts from Australia, New Zealand and the UK. The forums were complemented by a survey of clinicians involved in the management of people with severe asthma. We sought to: (i) identify areas of consensus among experts; (ii) define activities and resources required for the implementation of findings into practice; and (iii) identify specific priority areas for future research. Discussions identified areas of unmet need including assessment and diagnosis of severe asthma, models of care and treatment pathways, add-on treatment approaches and patient perspectives. We recommend development of education and training activities, clinical resources and standards of care documents, increased stakeholder engagement and public awareness campaigns and improved access to infrastructure and funding. Further, we propose specific future research to inform clinical decision-making and develop novel therapies. A concerted effort is required from all stakeholders (including patients, healthcare professionals and organisations and government) to integrate new evidence-based practices into clinical care and to advance research to resolve questions relevant to improving outcomes for people with severe asthma.

Airway Mucus Hyperconcentration in Non-Cystic Fibrosis Bronchiectasis

Rationale: Non-cystic fibrosis bronchiectasis is characterized by airway mucus accumulation and sputum production, but the role of mucus concentration in the pathogenesis of these abnormalities has not been characterized.Objectives: This study was designed to: 1) measure mucus concentration and biophysical properties of bronchiectasis mucus; 2) identify the secreted mucins contained in bronchiectasis mucus; 3) relate mucus properties to airway epithelial mucin RNA/protein expression; and 4) explore relationships between mucus hyperconcentration and disease severity.Methods: Sputum samples were collected from subjects with bronchiectasis, with and without chronic erythromycin administration, and healthy control subjects. Sputum percent solid concentrations, total and individual mucin concentrations, osmotic pressures, rheological properties, and inflammatory mediators were measured. Intracellular mucins were measured in endobronchial biopsies by immunohistochemistry and gene expression. MUC5B (mucin 5B) polymorphisms were identified by quantitative PCR. In a replication bronchiectasis cohort, spontaneously expectorated and hypertonic saline-induced sputa were collected, and mucus/mucin concentrations were measured.Measurements and Main Results: Bronchiectasis sputum exhibited increased percent solids, total and individual (MUC5B and MUC5AC) mucin concentrations, osmotic pressure, and elastic and viscous moduli compared with healthy sputum. Within subjects with bronchiectasis, sputum percent solids correlated inversely with FEV₁ and positively with bronchiectasis extent, as measured by high-resolution computed tomography, and inflammatory mediators. No difference was detected in MUC5B rs35705950 SNP allele frequency between bronchiectasis and healthy individuals. Hypertonic saline inhalation acutely reduced non-cystic fibrosis bronchiectasis mucus concentration by 5%.Conclusions: Hyperconcentrated airway mucus is characteristic of subjects with bronchiectasis, likely contributes to disease pathophysiology, and may be a target for pharmacotherapy.

PPARγ is reduced in the airways of non-CF bronchiectasis subjects and is inversely correlated with the presence of Pseudomonas aeruginosa

BACKGROUND

Chronic airway inflammation in conditions such as cystic fibrosis (CF) and non-CF bronchiectasis is characterised by a predominant neutrophilic inflammatory response, commonly due to the presence of pathogenic bacteria such as Pseudomonas aeruginosa. We hypothesised that down-regulation of the anti-inflammatory nuclear transcription regulator peroxisome proliferator-activated receptor gamma (PPARγ in non-CF bronchiectasis subjects may explain why this exuberant neutrophilic inflammation is able to persist unchecked in the inflamed airway.

METHODS

PPARγ gene expression was assessed in bronchoalveolar lavage fluid (BAL) of 35 macrolide naïve non-CF bronchiectasis subjects and compared with that in 20 healthy controls. Human RNA was extracted from pelleted BAL and PPARγ expression was determined by reverse-transcription quantitative PCR. Bacterial DNA was extracted from paired induced sputum and total bacterial load was determined by 16S rRNA qPCR. Quantification of individual bacterial species was achieved by qPCR.

RESULTS

PPARγ expression was lower in subjects with non-CF bronchiectasis compared with healthy control subjects (control: 1.00, IQR 0.55-1.44, n = 20 vs. Bronchiectasis: 0.49, IQR 0.12-0.89; n = 35; p<0.001, Mann-Whitney U test). This lower PPARγ expression correlated negatively with Pseudomonas aeruginosa (r = -0.53, n = 31; p = 0.002). No significant association was seen between PPARγ and total bacterial levels or levels Haemophilus influenzae.

CONCLUSION

PPARγ is expressed in low levels in the airways of non-CF bronchiectasis subjects, despite an aggressive inflammatory response. This low level PPARγ expression is particularly associated with the presence of high levels of P. aeruginosa, and may represent an intrinsic link with this bacterial pathogen.

Influenza epidemiology in patients admitted to sentinel Australian hospitals in 2015: the Influenza Complications Alert Network

The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with laboratory-confirmed influenza during the 2015 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals with an acute respiratory illness with influenza confirmed by nucleic acid detection. During the period 1 April to 30 October 2015 (the 2015 influenza season), 2,070 patients were admitted with confirmed influenza to one of 17 FluCAN sentinel hospitals. Of these, 46% were elderly (≥ 65 years), 15% were children (< 16 years), 5% were Indigenous Australians, 2.1% were pregnant and 75% had chronic co-morbidities. A high proportion were due to influenza B (51%). There were a large number of hospital admissions detected with confirmed influenza in this national observational surveillance system in 2015 with case numbers similar to that reported in 2014. The national immunisation program is estimated to avert 46% of admissions from confirmed influenza across all at-risk groups, but more complete vaccination coverage in target groups could further reduce influenza admissions by as much as 14%.

Adult non-cystic fibrosis bronchiectasis is characterised by airway luminal Th17 pathway activation

BACKGROUND

Non-cystic fibrosis (CF) bronchiectasis is characterised by chronic airway infection and neutrophilic inflammation, which we hypothesised would be associated with Th17 pathway activation.

METHODS

Th17 pathway cytokines were quantified in bronchoalveolar lavage fluid (BALF), and gene expression of IL-17A, IL-1β, IL-8 and IL-23 determined from endobronchial biopsies (EBx) in 41 stable bronchiectasis subjects and 20 healthy controls. Relationships between IL-17A levels and infection status, important clinical measures and subsequent Pseudomonas aeruginosa infection were determined.

RESULTS

BALF levels of all Th17 cytokines (median (IQR) pg/mL) were significantly higher in bronchiectasis than control subjects, including IL-17A (1.73 (1.19, 3.23) vs. 0.27 (0.24, 0.35), 95% CI 1.05 to 2.21, p<0.0001) and IL-23 (9.48 (4.79, 15.75) vs. 0.70 (0.43, 1.79), 95% CI 4.68 to 11.21, p<0.0001). However, BALF IL-17A levels were not associated with clinical measures or airway microbiology, nor predictive of subsequent P. aeruginosa infection. Furthermore, gene expression of IL-17A in bronchiectasis EBx did not differ from control. In contrast, gene expression (relative to medians of controls) in bronchiectasis EBx was significantly higher than control for IL1β (4.12 (1.24, 8.05) vs 1 (0.13, 2.95), 95% CI 0.05 to 4.07, p = 0.04) and IL-8 (3.75 (1.64, 11.27) vs 1 (0.54, 3.89), 95% CI 0.32 to 4.87, p = 0.02) and BALF IL-8 and IL-1α levels showed significant relationships with clinical measures and airway microbiology. P. aeruginosa infection was associated with increased levels of IL-8 while Haemophilus influenzae was associated with increased IL-1α.

CONCLUSIONS AND CLINICAL RELEVANCE

Established adult non-CF bronchiectasis is characterised by luminal Th17 pathway activation, however this pathway may be relatively less important than activation of non-antigen-specific innate neutrophilic immunity.

Influenza epidemiology, vaccine coverage and vaccine effectiveness in sentinel Australian hospitals in 2013: the Influenza Complications Alert Network

The National Influenza Program aims to reduce serious morbidity and mortality from influenza by providing public funding for vaccination to at-risk groups. The Influenza Complications Alert Network (FluCAN) is a sentinel hospital-based surveillance program that operates at 14 sites in all states and territories in Australia. This report summarises the epidemiology of hospitalisations with confirmed influenza, estimates vaccine coverage and influenza vaccine protection against hospitalisation with influenza during the 2013 influenza season. In this observational study, cases were defined as patients admitted to one of the sentinel hospitals, with influenza confirmed by nucleic acid testing. Controls were patients who had acute respiratory illnesses who were test-negative for influenza. Vaccine effectiveness was estimated as 1 minus the odds ratio of vaccination in case patients compared with control patients, after adjusting for known confounders. During the period 5 April to 31 October 2012, 631 patients were admitted with confirmed influenza at the 14 FluCAN sentinel hospitals. Of these, 31% were more than 65 years of age, 9.5% were Indigenous Australians, 4.3% were pregnant and 77% had chronic co-morbidities. Influenza B was detected in 30% of patients. Vaccination coverage was estimated at 81% in patients more than 65 years of age but only 49% in patients aged less than 65 years with chronic comorbidities. Vaccination effectiveness against hospitalisation with influenza was estimated at 50% (95% confidence interval: 33%, 63%, P<0.001). We detected a significant number of hospital admissions with confirmed influenza in a national observational study. Vaccine coverage was incomplete in at-risk groups, particularly non-elderly patients with medical comorbidities. Our results suggest that the seasonal influenza vaccine was moderately protective against hospitalisation with influenza in the 2013 season.

Australasian respiratory and emergency physicians do not use the pneumonia severity index in community-acquired pneumonia

BACKGROUND AND OBJECTIVE

The value of community-acquired pneumonia (CAP) severity scoring tools is almost exclusively reliant upon regular and accurate application in clinical practice. Until recently, the Australasian Therapeutic Guidelines has recommended the use of the Pneumonia Severity Index (PSI) in spite of poor user-friendliness.

METHODS

Electronic and postal survey of respiratory and emergency medicine physician and specialist registrar members of the Royal Australasian College was undertaken to assess the use of the PSI and the accuracy of its application to hypothetical clinical CAP scenarios. The confusion, urea, respiratory rate, blood pressure, age 65 or older (CURB-65) score was also assessed as a simpler alternative.

RESULTS

Five hundred thirty-six (228 respiratory, 308 emergency) responses were received. Only 12% of respiratory and 35% of emergency physicians reported using the PSI always or frequently. The majority were unable to accurately approximate PSI scores, with significantly fewer respiratory than emergency physicians recording accurate severity classes (11.8% vs 21%, OR 0.50, 95% CI: 0.37-0.68, P < 0.0001). In contrast, significantly more respiratory physicians were able to accurately calculate the CURB-65 score (20.4% vs 15%, OR 1.45, 95% CI: 1.10-1.91, P = 0.006).

CONCLUSIONS

Australasian specialist physicians primarily responsible for the acute management of CAP report infrequent use of the PSI and are unable to accurately apply its use to hypothetical scenarios. Furthermore, respiratory and emergency physicians contrasted distinctly in their use and application of the two commonest severity scoring systems--the recent recommendation of two further alternative scoring tools by Australian guidelines may add to this confusion. A simple, coordinated approach to pneumonia severity assessment across specialties in Australasia is needed.

Effect of long-term, low-dose erythromycin on pulmonary exacerbations among patients with non-cystic fibrosis bronchiectasis: the BLESS randomized controlled trial

IMPORTANCE

Macrolide antibiotics such as erythromycin may improve clinical outcomes in non-cystic fibrosis (CF) bronchiectasis, although associated risks of macrolide resistance are poorly defined.

OBJECTIVE

To evaluate the clinical efficacy and antimicrobial resistance cost of low-dose erythromycin given for 12 months to patients with non-CF bronchiectasis with a history of frequent pulmonary exacerbations.

DESIGN, SETTING, AND PARTICIPANTS

Twelve-month, randomized (1:1), double-blind, placebo-controlled trial of erythromycin in currently nonsmoking, adult patients with non-CF bronchiectasis with a history of 2 or more infective exacerbations in the preceding year. This Australian study was undertaken between October 2008 and December 2011 in a university teaching hospital, with participants also recruited via respiratory physicians at other centers and from public radio advertisements.

INTERVENTIONS

Twice-daily erythromycin ethylsuccinate (400 mg) or matching placebo.

MAIN OUTCOME MEASURES

The primary outcome was the annualized mean rate of protocol-defined pulmonary exacerbations (PDPEs) per patient. Secondary outcomes included macrolide resistance in commensal oropharyngeal streptococci and lung function.

RESULTS

Six-hundred seventy-nine patients were screened, 117 were randomized (58 placebo, 59 erythromycin), and 107 (91.5%) completed the study. Erythromycin significantly reduced PDPEs both overall (mean, 1.29 [95% CI, 0.93-1.65] vs 1.97 [95% CI, 1.45-2.48] per patient per year; incidence rate ratio [IRR], 0.57 [95% CI, 0.42-0.77]; P = .003), and in the prespecified subgroup with baseline Pseudomonas aeruginosa airway infection (mean difference, 1.32 [95% CI, 0.19-2.46]; P = .02). Erythromycin reduced 24-hour sputum production (median difference, 4.3 g [interquartile range [IQR], 1 to 7.8], P = .01) and attenuated lung function decline (mean absolute difference for change in postbronchodilator forced expiratory volume in the first second of expiration, 2.2 percent predicted [95% CI, 0.1% to 4.3%]; P = .04) compared with placebo. Erythromycin increased the proportion of macrolide-resistant oropharyngeal streptococci (median change, 27.7% [IQR, 0.04% to 41.1%] vs 0.04% [IQR, -1.6% to 1.5%]; difference, 25.5% [IQR,15.0% to 33.7%]; P < .001).

CONCLUSION AND RELEVANCE

Among patients with non-CF bronchiectasis, the 12-month use of erythromycin compared with placebo resulted in a modest decrease in the rate of pulmonary exacerbations and an increased rate of macrolide resistance.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12609000578202.

Clinical and epidemiological profile of patients with severe H1N1/09 pandemic influenza in Australia and New Zealand: an observational cohort study

Background Pandemic influenza H1N1/09 emerged in April 2009 and spread widely in Australia and New Zealand. Although an unprecedented number of cases required intensive care, comparative community-based studies with seasonal influenza strains have not shown any significant differences in clinical symptoms or severity. Methods The authors performed active surveillance on confirmed influenza-related admissions and compared the clinical profile of patients with pandemic H1N1/09 influenza and patients with seasonal influenza at eight hospitals in Australia and one hospital in New Zealand. Results During the 1 July and 30 November 2009, 560 patients with confirmed influenza were admitted, of which 478 had H1N1/09, and 82 had other seasonal strains. Patients with H1N1/09 influenza were younger, were more likely to have fever and were more likely to be pregnant but less likely to have chronic obstructive pulmonary disease and ischaemic heart disease than patients with seasonal strains. Other clinical features and comorbidities were reported in similar proportions. Admission to intensive care was required in 22% of patients with H1N1/09 influenza and 12% in patients with other strains. Hospital mortality was 5% in patients with H1N1 influenza. Conclusions The clinical features of H1N1/09 influenza and seasonal strains were similar in hospitalised patients. A higher proportion of patients had comorbidities than had been reported in community-based studies. Although the overall mortality was similar, the authors found evidence that H1N1/09 caused severe disease in a higher proportion of hospitalised patients.

The health behaviour and clinical characteristics of ambulance users with acute asthma

OBJECTIVE

This study sought to determine if ambulance service users differ in their health behaviours to "walk-in" patients attending an emergency department (ED) with acute asthma.

METHOD

Retrospective cross-sectional study of people with acute asthma stratified by ambulance use attending two ED. The health-promoting lifestyle profile and health risk appraisal tools assessed health and risk-taking behaviours, and the clinical variables assessed include: forced expiratory volume in 1 s, admission rates, severity, asthma medications, anxiety and depression.

RESULTS

Of the 142 patients, 26% used the ambulance service as transport to the ED. Ambulance users were significantly older than walk-in patients (40 vs 32 years, p < or = 0.05) and were less likely to return to follow-up appointments (odds ratio (OR) 2.93, 95% CI 1.16 to 7.37). Walk-in patients were more likely to report higher levels of education (OR 4.36, 95% CI 1.11 to 17.09). There was no difference between the groups for health-promoting behaviours. In reducing risks to their health and after adjusting for age and gender, there was a trend towards ambulance users undertaking preventive health measures more often than walk-in patients.

CONCLUSIONS

Ambulance users with acute asthma are more likely to be older, married and less educated. There is no evidence that this group is less responsible in managing their health; however, fewer ambulance users attended their follow-up appointment and the implication for ongoing care requires further investigation.

Effect of a simple educational intervention on the hospital management of community-acquired pneumonia

BACKGROUND AND OBJECTIVES

Both the speed of commencement and the appropriateness of i.v. antibiotic administration influence outcomes in patients hospitalized with community-acquired pneumonia (CAP). While quality improvement projects have been linked to better CAP management and outcomes, there are limited data evaluating simple and achievable interventions.

METHODS

A simple educational programme targeting rapid and appropriate antibiotic administration for the inpatient treatment of CAP was evaluated using a retrospective chart review of all patients admitted through the emergency department with CAP during 'pre-intervention' and 'post-intervention' periods.

RESULTS

There were 108 pre-intervention patients (56 women, median age 63 years) and 88 post-intervention patients (43 women, median age 61 years) included in the evaluation. Comparison of indicators of care in the post-intervention period with those in the pre-intervention period showed there were significant changes in: median time to antibiotic administration (2.5 h vs 3.5 h, 95% CI: 0-1.25, P = 0.01); subjects not prescribed macrolide antibiotics (2.3% vs 10.2%, 95% CI for OR 1.02-46.19, P = 0.04); hospital length of stay (3.5 vs 6 days, 95% CI: 1-3, P < 0.001) and mortality (0% vs 6.5%, 95% CI for OR 1.13 to infinity, P = 0.02).

CONCLUSION

A simple, inexpensive educational intervention was associated with significant improvements in the hospital management of CAP. The widespread introduction of similar programmes has the potential to effect substantial improvements in management, and possibly patient outcomes, and requires prospective confirmation in a larger, randomized sample.

Effect of Albuterol on Maximal Exercise Capacity in Cystic Fibrosis

BACKGROUND

Inhaled, short-acting beta-adrenergic agonists (SAbetaAs) are widely prescribed in cystic fibrosis (CF) subjects, despite a lack of convincing data for efficacy and the potential for these agents to result in airway instability. We tested the hypothesis that inhaled albuterol would improve maximal exercise performance in CF subjects with airflow obstruction, as a result of acute bronchodilation.

METHODS

Randomized, double-blind, placebo-controlled crossover study of the effect of inhaled albuterol on maximal exercise performance in 20 stable adult CF patients (mean +/- SD age, 23.3 +/- 6.1 years; FEV(1), 57.65 +/- 17.13% of predicted).

RESULTS

Ventilatory limitation to exercise was demonstrated in 16 subjects (80%). Significant bronchodilation occurred with exercise alone (end-exercise FEV(1), 2.24 +/- 0.8 L; vs preexercise FEV(1), 2.09 +/- 0.77 L; p < 0.0001), but albuterol resulted in significantly greater exercise-induced bronchodilation than placebo (change in FEV(1), 0.3 +/- 0.15 L vs 0.15 +/- 0.11 L; 95% confidence interval [CI], + 0.07 to + 0.23; p < 0.001). However, there was no difference in maximal workload achieved (albuterol, 158 +/- 46 W; vs placebo, 158 +/- 45 W; 95% CI, - 4.41 to + 4.71; p = 0.95), nor any other measure of exercise performance including maximal oxygen uptake.

CONCLUSIONS

Despite causing significant acute bronchodilation, inhaled albuterol did not improve maximal exercise performance in ventilatory-limited CF adults, adding to the body of literature that fails to show any clinical benefit of SAbetaAs in CF subjects. The current results provide further evidence to question the widespread use of these agents, although the potential for adrenergic beta-agonists to instead improve submaximal exercise performance merits further investigation.

The effects of salbutamol, beclomethasone, and dexamethasone on fibronectin expression by cultured airway smooth muscle cells

Possible mechanisms of adverse drug effects in asthma include worsening of cellular hyperplasia and stimulation of extracellular matrix deposition. In this study, salbutamol, dexamethasone and beclomethasone were investigated to ascertain their ability to induce mitogenesis and stimulate fibronectin expression in cultured canine airway smooth muscle cells. In cells maintained in serum-free media for 72 h, salbutamol (1 nM-10 microM) caused mitogenesis. The control cells had 2.57 +/- 0.34 x 10(5) cells per ml (mean +/- SEM, N = 13), while salbutamol (1 microM) caused a maximal increase in cell number to 3.57 +/- 0.23 x 10(5) cells/ml (P < 0.01). In cells stimulated to replicate by addition of either fetal bovine serum or canine serum, no additional mitogenic effect of salbutamol was seen. Salbutamol did not have a detectable quantitative effect on fibronectin matrix expression. The glucocorticoids, beclomethasone and dexamethasone, significantly altered fibronectin expression by cultured airway smooth muscle cells. Beclomethasone increased fibronectin expression, while dexamethasone decreased expression.

Cytokines and inflammatory mediators do not indicate acute infection in cystic fibrosis

Various treatment regimens and difficulties with research design are encountered with cystic fibrosis (CF) because no standard diagnostic criteria exist for defining acute respiratory exacerbations. This study evaluated the role of serial monitoring of concentrations of selected cytokines and inflammatory mediators in serum and sputum as predictors of respiratory exacerbation, as useful outcome measures for CF, and to guide therapy. Interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-alpha), neutrophil elastase-alpha-1-protease inhibitor complex (NE complex), protein, and alpha-1-protease inhibitor (alpha-1-PI) were measured in serum and sputum collected from CF patients during respiratory exacerbations and periods of well-being. Levels of NE complex, protein, and alpha-1-PI in sputum rose during respiratory exacerbations and fell after institution of antibiotic therapy (P = 0.078, 0.001, and 0.002, respectively). Mean (+/- standard error of the mean) levels of IL-8 and TNF-alpha were extremely high in sputum (13,780 +/- 916 and 249.4 +/- 23.5 ng/liter, respectively) but did not change significantly with clinical deterioration of the patient (P > 0.23). IL-8 and TNF-alpha were generally undetectable in serum, and therefore these measures were unhelpful. Drop in forced expiratory volume in 1 s was the only clinical or laboratory parameter that was close to being a determinant of respiratory exacerbation (P = 0.055). This study provides evidence of intense immunological activity occurring continually within the lungs of adult CF patients. Measurement of cytokines and inflammatory mediators in CF sputum is not helpful for identifying acute respiratory exacerbations.

Are antipseudomonal antibiotics really beneficial in acute respiratory exacerbations of cystic fibrosis?

BACKGROUND

Although anti-pseudomonal antibiotics are routinely used in the treatment of acute respiratory exacerbations of adult cystic fibrosis (CF), the specific efficacy of such treatment remains uncertain, the mechanism of action of these agents is not fully understood, and the role of sputum susceptibility testing in clinical decision making is controversial.

AIMS

We investigated the relationship between susceptibility testing and clinical outcome in adult CF patients colonised with Pseudomonas aeruginosa.

METHODS

Sputum samples were collected before, during and after respiratory exacerbations from 31 admissions (17 patients). Sputum colony counts and MIC of P. aeruginosa were performed.

RESULTS

Sputum colony counts did not change significantly during or after intravenous (IV) antibiotic therapy. Clinical outcome parameters (lung function, 12-minute walking distance, sputum weight and quality of life) were compared with susceptibility of P. aeruginosa colonies isolated at admission to the antibiotics used, and no correlation was evident. There was no evidence for the development of cross-resistance and there was no change in the proportion of mucoid colonies with therapy.

CONCLUSIONS

While this study has a small patient sample size, it highlights the inconsistency of the role of antipseudomonal drugs also shown in other similar studies. The presence of P. aeruginosa in sputum of acutely ill CF patients prompts us to prescribe i.v. antipseudomonal drugs. If this approach was valid, we would expect to find a reduction in sputum colony counts and improvement in clinical parameters with the use of antibiotics to which the organisms were sensitive. The fact that such a relationship cannot be consistently demonstrated in this and other studies suggests that the use of antipseudomonal therapy in these patients requires more critical bacteriological and clinical evaluation.

Buteyko breathing techniques in asthma: a blinded randomised controlled trial

OBJECTIVE

To evaluate the effect of Buteyko breathing techniques (BBT) in the management of asthma.

DESIGN

Prospective, blinded, randomised study comparing the effect of BBT with control classes in 39 subjects with asthma. The study was conducted from January 1995 to April 1995.

PARTICIPANTS AND SETTING

Subjects recruited from the community, aged 12 to 70 years, with asthma and substantial medication use.

MAIN OUTCOME MEASURES

Medication use; morning peak expiratory flow (PEF); forced expiratory volume in one second (FEV1); end-tidal (ET) CO2; resting minute volume (MV); and quality of life (QOL) score, measured at three months.

RESULTS

No change in daily PEF or FEV1 was noted in either group. At three months, the BBT group had a median reduction in daily beta 2-agonist dose of 904 micrograms (range, 29 micrograms to 3129 micrograms), whereas the control group had a median reduction of 57 micrograms (range, -2343 micrograms to 1143 micrograms) (P = 0.002). Daily inhaled steroid dose fell 49% (range, -100% to 150%) for the BBT group and 0 (range, -82% to +100%) for the control group (P = 0.06). A trend towards greater improvement in QOL score was noted for BBT subjects (P = 0.09). Initial MV was high and similar in both groups; by three months, MV was lower in the BBT group than in the control group (P = 0.004). ET CO2 was low in both groups and did not change with treatment.

CONCLUSION

Those practising BBT reduced hyperventilation and their use of beta 2-agonists. A trend toward reduced inhaled steroid use and better quality of life was observed in these patients without objective changes in measures of airway calibre.

Home intravenous therapy in cystic fibrosis: a prospective randomized trial examining clinical, quality of life and cost aspects

In this study, we set out to determine if home intravenous (i.v.) antibiotic therapy in adult patients with cystic fibrosis (CF) is a feasible, effective and less costly alternative to hospitalization, and to assess the impact of home therapy on quality of life. The study was a prospective, randomized, two-factor mixed design involving adults presenting with respiratory exacerbations of CF. Patients were randomized such that they were discharged home after 2-4 days, or remained in hospital. Seventeen patients had 31 admissions (13 home and 18 hospital). Following 10 days of therapy, there were no significant differences between home or hospital arms with respect to body weight, 12 minute walking distance, sputum weight, pulse oximetry, or improvement in lung function (forced expiratory volume in one second (FEV1), or forced vital capacity (FVC)). Patients who remained in hospital were less fatigued and noted a greater degree of mastery. Patients discharged early noted less disruption to their family life, personal life and sleeping pattern. The total cost for the home therapy arm was approximately half that of the hospital therapy arm. Home intravenous antibiotic therapy in patients with cystic fibrosis was a feasible, cost-effective alternative to receiving therapy in hospital. Although there was no clinical compromise associated with home therapy, there were advantages and disadvantages in terms of quality of life.

Home intravenous therapy in cystic fibrosis: a prospective randomized trial examining clinical, quality of life and cost aspects

In this study, we set out to determine if home intravenous (i.v.) antibiotic therapy in adult patients with cystic fibrosis (CF) is a feasible, effective and less costly alternative to hospitalization, and to assess the impact of home therapy on quality of life. The study was a prospective, randomized, two-factor mixed design involving adults presenting with respiratory exacerbations of CF. Patients were randomized such that they were discharged home after 2-4 days, or remained in hospital. Seventeen patients had 31 admissions (13 home and 18 hospital). Following 10 days of therapy, there were no significant differences between home or hospital arms with respect to body weight, 12 minute walking distance, sputum weight, pulse oximetry, or improvement in lung function (forced expiratory volume in one second (FEV1), or forced vital capacity (FVC)). Patients who remained in hospital were less fatigued and noted a greater degree of mastery. Patients discharged early noted less disruption to their family life, personal life and sleeping pattern. The total cost for the home therapy arm was approximately half that of the hospital therapy arm. Home intravenous antibiotic therapy in patients with cystic fibrosis was a feasible, cost-effective alternative to receiving therapy in hospital. Although there was no clinical compromise associated with home therapy, there were advantages and disadvantages in terms of quality of life.

Homologous serum increases fibronectin expression and cell adhesion in airway smooth muscle cells

This study describes altered patterns of growth and upregulation of fibronectin expression of cultured canine airway smooth muscle cells grown in homologous serum, which provides a model of the vascular leakage occurring in asthma, compared to fetal bovine serum (FBS). Cells were incubated in increasing concentrations of serum (2.5-40%) for 72 hours. Both homologous serum and FBS caused cellular proliferation which reached a maximum increase at 2.5-5% serum concentration. Differences in the cellular responses to the two types of sera were noted at higher concentrations of sera. At a concentration of 40% FBS, airway smooth muscle cells increased in number by 307 +/- 16% (n = 5) compared to serum-free control cells, whereas in canine serum the increase in growth was significantly smaller, 239 +/- 25% (n = 7) (P < 0.05). Airway fibrocytes similarity treated increased in number by 256 +/- 43% (n = 3) in 40% FBS, but exhibited a reduction in cell number to 80 +/- 10% (n = 3) of controls in 40% homologous serum (P < 0.05). Smooth muscle cells demonstrated a dose-dependent increase in fibronectin expression when grown in homologous serum but not in FBS, suggesting phenotypic change occurred in these cells when exposed to homologous serum. These data suggest that the leakage of plasma in the asthmatic airway may trigger phenotypic change in both airway smooth muscle cells and airway fibrocytes leading to cellular proliferation and expression of extracellular matrix molecules. These in vitro changes are consistent with the histological findings in clinical asthma.

Measuring the systemic effects of inhaled beclomethasone: timed morning urine collections compared with 24 hour specimens

BACKGROUND

Inhaled glucocorticoid therapy has systemic effects including hypothalamic-pituitary-adrenal (HPA) suppression. The optimal test for detecting these effects has not been defined.

METHODS

Timed urine collections and 09.00 hour plasma cortisol levels were obtained from 12 normal volunteers receiving inhaled placebo, beclomethasone (BDP) 800 or 2000 micrograms/day. The 24 hour urine samples were collected as follows: first hour after waking (hour 1), the next two hours after waking (hours 2 and 3), remainder of day, and overnight, with results expressed as urine cortisol/creatinine (UCC) ratios and as hourly cortisol output in the timed collections. Twenty four hour urinary cortisol excretion was also calculated. Medication was blinded and given in random order with a washout period of at least 11 days between each treatment arm.

RESULTS

None of the UCC ratios changed with BDP 800 micrograms/day. UCC ratios at hour 1, hour 2 and 3, and overnight, and 24 hour urinary free cortisol excretion were reduced after BDP 2000 micrograms/day, whilst remainder of day UCC ratio and the plasma cortisol level did not change significantly. Cortisol output showed similar changes. In a follow up study BDP 1400 micrograms/day also reduced UCC ratios for the first two hours after waking.

CONCLUSIONS

UCC ratios are as sensitive as the more cumbersome 24 hour urinary free cortisol excretion, and more sensitive than single morning plasma cortisol measurements, in detecting the effects of inhaled beclomethasone on the HPA axis.

Airway smooth muscle proliferation in asthma: the potential of vascular leakage to contribute to pathogenesis

Proliferation of the non-vascular smooth muscle in the walls of the bronchi and bronchioles is a prominent histopathological feature of asthma and is thought to contribute to airway hyperreactivity and narrowing. Increased vascular permeability with plasma leakage is also a feature of asthma pathology and causes submucosal oedema. We hypothesize that, in asthmatics, the accumulation of enriched plasma in the environment surrounding airway smooth muscle promotes respiratory smooth muscle mitogenesis and hyperplasia. This situation represents the in vivo correlate of the increase in airway smooth muscle cell growth seen in vitro with increasing concentrations of serum in the culture medium. Thus, we hypothesize that vascular leakage in the airways in asthma is a primary pathogenic event leading to airway smooth muscle hyperplasia and hypertrophy, and consequently airway narrowing, promoting the characteristic bronchial hyperreactivity associated with narrowing of the airway lumen.

Heparin inhibits the immediate response to antigen in the skin and lungs of allergic subjects

Although heparin is used as an anticoagulant, its biologic function remains unclear. Substantial evidence exists that suggests it may modulate many aspects of immune function and inflammation. We demonstrated, in a double-blind, placebo-controlled, crossover study involving 10 allergic subjects, that a small dose of heparin (25 U/kg) administered intravenously 10 min before challenge reduced the acute cutaneous reaction to 10 allergens and histamine from a group-average sum of mean (+/- SD) wheal diameters at a baseline of 29.9 +/- 10 mm and after normal saline placebo (29.5 +/- 10.7 mm) to after heparin (14.4 +/- 10.4 mm) (p < 0.02, Wilcoxon's signed rank test). In 15 subjects with asthma and dust mite allergy, nebulized heparin 20,000 units administered in a double-blind, placebo-controlled, crossover fashion 10 min before challenge inhibited the bronchospasm induced by inhaled dust mite extract. Log2 of the provocative dose of mite extract causing a 20% fall in FEV1 at baseline was 4.1 +/- 1.5 protein nitrogen units (PNU); after normal saline it was 4.5 +/- 2.0 PNU, and after heparin it was 5.1 +/- 2.5 PNU (p = 0.04). These data suggest heparin may have an inhibitory role in acute mast-cell-mediated allergic inflammation.

Corticosteroids in acute severe asthma: effectiveness of low doses

BACKGROUND

Although the need for corticosteroids in acute severe asthma is well established the appropriate dose is not known.

METHODS

The response to intravenous hydrocortisone 50 mg (low dose), 100 mg (medium dose), and 500 mg (high dose), administered every six hours for 48 hours and followed by oral prednisone, was compared in patients with acute asthma in a double blind randomised study. After initial emergency treatment with bronchodilators subjects received oral theophylline or intravenous aminophylline and nebulised salbutamol four hourly. Patients were given low, medium, or high doses of intravenous hydrocortisone and then 20, 40, or 60 mg/day respectively of oral prednisone with a reducing regimen over the following 12 days. Beclomethasone dipropionate, 400 micrograms twice daily by metered dose inhaler, was also started. Peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), and visual analogue dyspnoea scores (VAS) were recorded daily in hospital and PEF and VAS twice daily after discharge for a total of 12 days.

RESULTS

The 66 subjects (40 female) who completed the study had a mean (SD) age of 31(14) years. On presentation mean (SD) FEV1% predicted in the low (n = 22), medium (n = 20), and high dose (n = 24) groups was 17(13), 19(12), and 19(11) and after emergency bronchodilator treatment 32(20), 30(12), and 36(13). After 24 hours of treatment the respective post-bronchodilator FEV1% predicted values were 62(22), 62(23), and 65(28) compared with 71(24), 69(22), and 71(24) after 48 hours. No significant difference between the groups was detected. PEF and VAS improved with treatment over the 12 days but was not influenced by steroid dose.

CONCLUSIONS

Hydrocortisone 50 mg intravenously four times a day for two days followed by low dose oral prednisone is as effective in resolving acute severe asthma as 200 or 500 mg of hydrocortisone followed by higher doses of prednisone.

House dust control and asthma: a placebo-control trial of cleaning air filtration

Using a placebo-control single-blind crossover trial, we investigated the effects of dust control measures alone and combined with electrostatic and high efficiency particulate air filters in the bedrooms of patients with asthma. Of 12 young asthmatics allergic to house dust and dust mite who entered the trial, nine completed all four 2-week intervals. No statistically significant improvement in symptom scores or peak expiratory flow above that recorded during the placebo interval occurred during any treatment phase. We conclude that house dust suppression adds little to the management of otherwise well controlled young asthmatic patients.