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EXHALED MARKERS AT COPD EXACERBATIONS
Exacerbations of COPD are an important cause of morbidity in COPD and affect disease progression. There is therefore a need to study the inflammatory mechanisms of exacerbations and, as biopsy studies are difficult at exacerbation, non-invasive measurements are essential. In this issue of Thorax Biernacki and colleagues describe the measurement of the inflammatory mediator leukotriene B4 (LTB4) and 8-isoprostane as a marker of oxidative stress, both in exhaled breath condensate. This study is particularly welcome as it has been performed exclusively in primary care and shows that these measurements are feasible in the community. All the exacerbations had the three major criteria of increased dyspnoea, sputum volume and purulence. Oral steroids were not used as the exacerbations were not considered to be sufficiently severe. At exacerbation, rises were seen in the exhaled markers which decreased by 2 weeks and had fallen further by 2 months, emphasising the important point that inflammatory changes associated with COPD exacerbations last a considerable time. It is interesting to speculate whether the levels of exhaled markers would have decreased faster if oral steroids had been used at exacerbation.
See page 294
LONG TERM NO PLUS OXYGEN
Pulmonary hypertension is an important complication of severe COPD although, despite considerable effort over the years, there has been difficulty with treatments aimed at reducing pulmonary artery pressure. In this issue of Thorax Block and colleagues report the results of the first randomised controlled trial of the use of a combination of nitric oxide (NO) and long term oxygen therapy (LTOT) for 3 months in patients with severe COPD. A feature of this study was that the NO and oxygen mixture was given through a special pulsed inhalation device suitable for domiciliary use. Improvement in pulmonary haemodynamics was found with the combination relative to LTOT alone. More important, there were no reductions in blood pressure or arterial oxygen with the combination as has been observed with previous treatments. The study is further discussed in an accompanying editorial by Pepke-Zaba and Morrell who point out that a number of issues need to be addressed including safety and also whether the observed haemodynamic changes will translate into improvements in exercise tolerance and quality of life.
IS IT ALL TH2 CYTOKINES?
The Th2 subclass of T helper lymphocytes is considered to play a crucial role in the inflammatory response in asthma. In this issue Brown and colleagues report an interesting study of bronchoalveolar lavage (BAL) fluid samples taken from 60 children before elective surgery and analysed using flow cytometry. A new feature of this study is that the authors collected BAL fluid specimens to study cytokine profiles rather than circulating T cells, and also the use of flow cytometry. Contrary to expectations, interferon gamma (Th1) cells were more common in the BAL fluid of atopic asthmatic children than in BAL fluid from atopic non-asthmatic patients or normal control subjects. The authors suggest that interferon gamma is an important cytokine in the development of childhood asthma and question the hypothesis that asthma is a predominantly Th2 driven condition.
See page 311
DISAPPOINTMENT FOR ASTHMA AND HOMEOPATHY
As White and colleagues point out in their paper, childhood asthma is frequently treated with homeopathy although there is no good evidence for its benefit in asthma. They report a multicentre randomised double blind study, performed in five primary care practices and followed for 12 months, of the addition of homeopathy to standard treatment in childhood asthma. Individualised homeopathy was provided by trained classical homeopaths who provided the homeopathy according to their normal practice. There was no significant change in the primary outcome measure—an active quality of life score. In addition, there were no changes in other outcomes such as exacerbations. The authors point out that children were studied in this trial as they were considered more likely to respond to the intervention. Thus, there is no current evidence that homeopathic remedies should be used in the management of childhood asthma.
See page 317
AMINOPHYLLINE VERSUS SALBUTAMOL IN CHILDHOOD ASTHMA
The study by Roberts and colleagues addresses an important issue in routine clinical practice. It describes a randomised trial of intravenous salbutamol bolus compared with aminophylline infusion in children with severe acute asthma who have not responded to standard treatment with nebulisers and systemic steroids. The study found no difference between the two treatments at 2 hours, although aminophylline had the advantage that it was associated with a shorter stay in hospital and there was a trend towards less use of supplementary oxygen therapy. As South points out in his commentary on the paper, there are a number of possible second line treatments for acute childhood asthma that can be now used, although evaluation of these is particularly complex. However, South also adds that any treatment used in this situation must be administered optimally and safely.