The airways microbiome of individuals with asthma treated with high and low doses of inhaled corticosteroids.

BACKGROUND: Inhaled corticosteroids (ICS) are the mainstay of asthma treatment, but evidence suggests a link between ICS usage and increased rates of respiratory infections. We assessed the composition of the asthmatic airways microbiome in asthma patients taking low and high dose ICS and the stability of the microbiome over a 2 week period. METHODS: We prospectively recruited 55 individuals with asthma. Of these, 22 were on low-dose ICS and 33 on high-dose ICS (16 on budesonide, 17 on fluticasone propionate). Sputum from each subject underwent DNA extraction, amplification and 16S rRNA gene sequencing of the bacterial component of the microbiome. 19 subjects returned for further sputum induction after 24 h and 2 weeks. RESULTS: A total of 5,615,037 sequencing reads revealed 167 bacterial taxa in the asthmatic airway samples, with the most abundant being Streptococcus spp. No significant differences in sputum bacterial load or overall community composition were seen between the low- and high-dose ICS groups. However, Streptococcus spp. showed significantly higher relative abundance in subjects taking low-dose ICS (p = 0.002). Haemophilus parainfluenzae was significantly more abundant in subjects on high-dose fluticasone propionate than those on high-dose budesonide (p = 0.047). There were no statistically significant changes in microbiota composition over a 2-week period. DISCUSSION: Whilst no significant differences were observed between the low- and high-dose ICS groups, increased abundance of the potential pathogen H. parainfluenzae was observed in patients taking high-dose fluticasone propionate compared to those taking high-dose budesonide. The microbiota were stable over fourteen days, providing novel evidence of the established community of bacteria in the asthmatic airways. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02671773.

The Its Not JUST Idiopathic pulmonary fibrosis Study (INJUSTIS): description of the protocol for a multicentre prospective observational cohort study identifying biomarkers of progressive fibrotic lung disease.

Introduction: The Its Not JUST Idiopathic pulmonary fibrosis Study (INJUSTIS) is a multicentre, prospective, observational cohort study. The aims of this study are to identify genetic, serum and other biomarkers that may identify specific molecular mechanisms, reflecting disease endotypes that are shared among patients with progressive pulmonary fibrosis regardless of aetiology. Furthermore, it is anticipated that these biomarkers will help predict fibrotic activity that may identify patterns of disease behaviour with greater accuracy than current clinical phenotyping. Methods and analysis: 200 participants with the multidisciplinary team confirmed fibrotic lung disease (50 each of rheumatoid-interstitial lung disease (ILD), asbestosis, chronic hypersensitivity pneumonitis and unclassifiable ILD) and 50 idiopathic pulmonary fibrosis participants, recruited as positive controls, will be followed up for 2 years. Participants will have blood samples, lung function tests, quality of life questionnaires and a subgroup will be offered bronchoscopy. Participants will also be given the option of undertaking blinded home handheld spirometry for the first 3 months of the study. The primary end point will be identification of a biomarker that predicts disease progression, defined as 10% relative change in forced vital capacity (FVC) or death at 12 months. Ethics and dissemination: The trial has received ethical approval from the National Research Ethics Committee Nottingham (18/EM/0139). All participants must provide written informed consent. The trial will be overseen by the INJUSTIS steering group that will include a patient representative, and an independent chairperson. The results from this study will be submitted for publication in peer-reviewed journals and disseminated at regional and national conferences. Trial registration number: NCT03670576.

Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study.

INTRODUCTION: Identifying acute hypercapnic respiratory failure is crucial in the initial management of acute exacerbations of COPD. Guidelines recommend obtaining arterial blood samples but these are more difficult to obtain than venous. We assessed whether blood gas values derived from venous blood could replace arterial at initial assessment. METHODS: Patients requiring hospital treatment for an exacerbation of COPD had paired arterial and venous samples taken. Bland-Altman analyses were performed to assess agreement between arterial and venous pH, CO2 and HCO3-. The relationship between SpO2 and SaO2 was assessed. The number of attempts and pain scores for each sample were measured. RESULTS: 234 patients were studied. There was good agreement between arterial and venous measures of pH and HC)3- (mean difference 0.03 and -0.04, limits of agreement -0.05 to 0.11 and -2.90 to 2.82, respectively), and between SaO2 and SpO2 (in patients with an SpO2 of >80%). Arterial sampling required more attempts and was more painful than venous (mean pain score 4 (IQR 2-5) and 1 (IQR 0-2), respectively, p<0.001). CONCLUSIONS: Arterial sampling is more difficult and more painful than venous sampling. There is good agreement between pH and HCO3- values derived from venous and arterial blood, and between pulse oximetry and arterial blood gas oxygen saturations. These agreements could allow the initial assessment of COPD exacerbations to be based on venous blood gas analysis and pulse oximetry, simplifying the care pathway and improving the patient experience.

Respiratory muscle specific warm-up and elite swimming performance.

BACKGROUND: Inspiratory muscle training has been shown to improve performance in elite swimmers, when used as part of routine training, but its use as a respiratory warm-up has yet to be investigated. AIM: To determine the influence of inspiratory muscle exercise (IME) as a respiratory muscle warm-up in a randomised controlled cross-over trial. METHODS: A total of 15 elite swimmers were assigned to four different warm-up protocols and the effects of IME on 100 m freestyle swimming times were assessed.Each swimmer completed four different IME warm-up protocols across four separate study visits: swimming-only warm-up; swimming warm-up plus IME warm-up (2 sets of 30 breaths with a 40% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); swimming warm-up plus sham IME warm-up (2 sets of 30 breaths with a 15% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); and IME-only warm-up. Swimmers performed a series of physiological tests and scales of perception (rate of perceived exertion and dyspnoea) at three time points (pre warm-up, post warm-up and post time trial). RESULTS: The combined standard swimming warm-up and IME warm-up were the fastest of the four protocols with a 100 m time of 57.05 s. This was significantly faster than the IME-only warm-up (mean difference=1.18 s, 95% CI 0.44 to 1.92, p<0.01) and the swim-only warm-up (mean difference=0.62 s, 95% CI 0.001 to 1.23, p=0.05). CONCLUSIONS: Using IME combined with a standard swimming warm-up significantly improves 100 m freestyle swimming performance in elite swimmers.