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The effect on Paco2 of high concentration oxygen therapy when administered to patients with severe exacerbations of asthma is uncertain.106 patients with severe exacerbations of asthma presenting to the Emergency Department were randomised to high concentration oxygen (8 l/min via medium concentration mask) or titrated oxygen (to achieve oxygen saturations between 93% and 95%) for 60 min. Patients with chronic obstructive pulmonary disease or disorders associated with hypercapnic respiratory failure were excluded. The transcutaneous partial pressure of carbon dioxide (Ptco2) was measured at 0, 20, 40 and 60 min. The primary outcome variable was the proportion of patients with a rise in Ptco2 ≥4 mm Hg at 60 min.The proportion of patients with a rise in Ptco2 ≥4 mm Hg at 60 min was significantly higher in the high concentration oxygen group, 22/50 (44%) vs. 10/53 (19%), RR 2.3 (95% CI 1.2 to 4.4, p0.006). The high concentration group had a higher proportion of patients with a rise in Ptco2 ≥8 mm Hg, 11/50 (22%) vs. 3/53 (6%), RR 3.9 (95% CI 1.2 to 13.1, p=0.016). All 10 patients with a final Ptco2 ≥45 mm Hg received high concentration oxygen therapy, and in five there was an increase in Ptco2 ≥10 mm Hg.High concentration oxygen therapy causes a clinically significant increase in Ptco2 in patients presenting with severe exacerbations of asthma. A titrated oxygen regime is recommended in the treatment of severe asthma, in which oxygen is administered only to patients with hypoxaemia, in a dose that relieves hypoxaemia without causing hyperoxaemia. Clinical trial number ACTRN12607000131459.

Background: There is concern that long-acting β agonist (LABA) drugs may increase the risk of asthma mortality. Methods: A meta-analysis was conducted of asthma deaths in randomised controlled clinical trials from the GlaxoSmithKline database that compared salmeterol with a non-LABA comparator treatment in asthma. The Peto one-step method was used to determine the risk overall (all studies) and in derived datasets based on inhaled corticosteroid (ICS) use. Results: There were 35 asthma deaths in 215 studies with 106 575 subjects. Two studies (SMART and SNS) contributed 30/35 (86%) asthma deaths, the overall findings largely reflecting the characteristics of these studies. The odds ratio for risk of asthma mortality with salmeterol was 2.7 (95% CI 1.4 to 5.3). In 54 placebo controlled studies the risk of death from asthma in patients not prescribed ICS was 7.3 (95% CI 1.8 to 29.4). In 127 studies in which patients were prescribed ICS, the risk of asthma death was 2.1 (95% CI 0.6 to 7.9). In 63 studies in which patients were randomised to receive the combination salmeterol/fluticasone propionate inhaler or ICS, there were no asthma deaths among 22 600 patients. Conclusions: Salmeterol monotherapy in asthma increases the risk of asthma mortality and this risk is reduced with concomitant ICS therapy. There is no evidence that combination salmeterol/fluticasone propionate therapy is associated with an increased risk of asthma mortality, although this interpretation is limited by the low statistical power of available studies.

Context: International guidelines recommend the routine use of oxygen therapy in the treatment of myocardial infarction (MI). Objective: To undertake a systematic review and metaanalysis of randomised placebo-controlled trials of oxygen therapy in MI. Data sources: Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, EMBASE and CINHAL. Study selection: Randomised placebo-controlled trials of oxygen therapy in MI. Data extraction: The primary clinical outcome was mortality. Results: Two of 51 potential studies met the inclusion criteria. The one study with substantive clinical outcome data reported that in uncomplicated MI, high-flow oxygen was associated with a non-significant increased risk of death (risk ratio 2.9, 95% CI 0.8 to 10.3, p = 0.08) and a greater serum aspartate aminotransferase level (difference 19.2 IU/ml, 95% CI 0 to 38.4, p = 0.05) than room air. Conclusion: The limited evidence that does exist suggests that the routine use of high-flow oxygen in uncomplicated MI may result in a greater infarct size and possibly increase the risk of mortality.

INTRODUCTION: The purpose of the quality standards document is to provide healthcare professionals, commissioners, service providers and patients with a guide to standards of care that should be met for home oxygen provision in the UK, together with measurable markers of good practice. Quality statements are based on the British Thoracic Society (BTS) Guideline for Home Oxygen Use in Adults.METHODS: Development of BTS Quality Standards follows the BTS process of quality standard production based on the National Institute for Health and Care Excellence process manual for the development of quality standards.RESULTS: 10 quality statements have been developed, each describing a key marker of high-quality, cost-effective care for home oxygen use, and each statement is supported by quality measures that aim to improve the structure, process and outcomes of healthcare.DISCUSSION: BTS Quality Standards for home oxygen use in adults form a key part of the range of supporting materials that the society produces to assist in the dissemination and implementation of a guideline's recommendations.

Background Exacerbation of COPD is the second commonest reason for hospital admission, with high subsequent readmission and mortality rates among those who survive to discharge. Risk stratification would inform efficient use of services. Methods Consecutive patients admitted with an exacerbation of COPD who survived to discharge were recruited by screening admissions units and searching coding records. Six UK hospitals took part: the derivation and internal validation cohort involved the same two hospitals at different time periods, and the external validation involved four hospitals. Clinical data, and 90-day death and readmission rates were recorded. Multivariate logistic regression analysis was used to develop a tool to predict 90-day readmission, or death without readmission. Performance was assessed by the area under the receiver operator characteristic (AUROC) curve. Results 2,417 patients were analysed (derivation 824, internal validation 824, external validation 791). Female 54.0%, mean (SD) age 72.6 (10.2) years, FEV1 45.3 (18.2) %predicted, 90-day readmission or death 38.7%. In the derivation cohort, the five strongest predictors (odds ratio, 95% confidence interval given for whole population) were: two or more Previous admissions in the preceding year (OR 3.17, 95% CI 2.59–3.87), stable-state dyspnoea assessed by the Extended MRCD score (eMRCD 4 OR 1.46, 95% CI 1.12–1.90; eMRCD 5a OR 2.35 95% CI 1.79–3.08; eMRCD 5b OR 3.00 95% CI 2.19–4.11), Age 80 or more (OR 1.48, 95% CI 1.22–1.81), cor-pulmonale “Right heart failure” (OR 1.93, 95% CI 1.41–2.66), Left heart failure (OR 1.45, 95% CI 1.07–1.97). Two or more previous admissions and eMRCD 5b were assigned a score of 3, eMRCD 5a scored 2, while eMRCD 4 and remaining indices scored 1. The risk of readmission and/or death is shown in Table 1. The AUROC was: derivation 0.73 (95% CI 0.69–0.77); internal validation 0.68 (95% CI 0.64–0.72); and external validation 0.70 (95% CI 0.66–0.73). Discussion In patients hospitalised with an exacerbation of COPD the PEARL score is a robust predictor of readmission and death and may be used to inform efficient use of resources according to risk.

Background Titrated oxygen has been shown to significantly reduce mortality in patients presenting with acute exacerbations of chronic obstructive pulmonary disease (COPD) 1 . All patients at risk of type 2 respiratory failure (T2RF) should be administered oxygen in accordance with British Thoracic Society Guidelines. However, the NEWS system proposed by the Royal College of Physicians makes no allowance for patients at risk of T2RF and may lead to potential over oxygenation in this group of patients 2 . Objective To assess the use of the NEWS in patients with T2RF in our district general hospital and to assess the safety of a modified system. Methods Patients were selected from the Medical Admissions Unit. Inclusion criteria were oxygen prescription or oxygen in situ . Data were collected over 5 consecutive days. Conventional NEWS for these patients were compared with a system currently being piloted at Salford Royal Foundation Trust with modified oxygen saturation levels (SpO2) for patients at risk of T2RF (Table 1) Results 69 patients were assessed. 32% (22/69) had risk factors for T2RF. 21 had COPD and one had sleep apnoea. 55% (12/22) had oxygen saturations in their target range or were above target saturations but on air. 32% (7/22) were on oxygen and had saturations above 92%. 14% (3/22) had saturations below 88%. 73% (16/22) of at risk patients had their scores altered when using the Salford EWS system. 69% (11/16) of these patients had their scores reduced. 4 patient’s scores were reduced by 3, 4 were reduced by 2 and 3 were reduced by 1. 31% (5/16) of patient’s scores were increased. 4 scores were increased by 2 and 1 increased by 1. The score differences were due to over oxygenation. Conclusions The current NEWS system appears to increase the risk of over oxygenation in patients at risk of T2RF. Using a modified score for patients at risk of T2RF will reduces this risk. With thanks Ronan O’Driscoll, Salford Foundation Trust for use of the modified Salford NEWS chart

We appreciate the comments by Snelson and Tunnicliffe1 regarding our study of the effects of high concentration oxygen therapy in acute exacerbations of asthma.2 We concur with the view that the effect of high concentration oxygen therapy on arterial carbon dioxide pressure (PaCO2) is not clinically relevant in all patients presenting to the emergency department (ED) with acute severe asthma. However, we consider that the 3.9-fold …