MyAirCoach: The use of home-monitoring and mHealth systems to predict deterioration in asthma control and the occurrence of asthma exacerbations; Study protocol of an observational study

© Published by the BMJ Publishing Group Limited. Introduction Asthma is a variable lung condition whereby patients experience periods of controlled and uncontrolled asthma symptoms. Patients who experience prolonged periods of uncontrolled asthma have a higher incidence of exacerbations and increased morbidity and mortality rates. The ability to determine and to predict levels of asthma control and the occurrence of exacerbations is crucial in asthma management. Therefore, we aimed to determine to what extent physiological, behavioural and environmental data, obtained by mobile healthcare (mHealth) and home-monitoring sensors, as well as patient characteristics, can be used to predict episodes of uncontrolled asthma and the onset of asthma exacerbations. Methods and analysis In an 1-year observational study, patients will be provided with mHealth and home-monitoring systems to record daily measurements for the first-month (phase I) and weekly measurements during a follow-up period of 11 months (phase II). Our study population consists of 150 patients, aged ≥18 years, with a clinician's diagnosis of asthma, currently on controller medication, with uncontrolled asthma and/or minimally one exacerbation in the past 12 months. They will be enrolled over three participating centres, including Leiden, London and Manchester. Our main outcomes are the association between physiological, behavioural and environmental data and (1) the loss of asthma control and (2) the occurrence of asthma exacerbations. Ethics This study was approved by the Medical Ethics Committee of the Leiden University Medical Center in the Netherlands and by the NHS ethics service in the UK. Trial registration number NCT02774772

Continuous wave optical parametric oscillator for quartz-enhanced photoacoustic trace gas sensing

A continuous wave optical parametric oscillator, generating up to 300 mW idler output in the 3–4 μm wavelength region, and pumped by a fiber-amplified DBR diode laser is used for trace gas detection by means of quartz-enhanced photoacoustic spectroscopy (QEPAS). Mode-hop-free tuning of the OPO output over 5.2 cm-1 and continuous spectral coverage exceeding 16.5 cm-1 were achieved via electronic pump source tuning alone. Online monitoring of the idler wavelength, with feedback to the DBR diode laser, provided an automated closed-loop control allowing arbitrary idler wavelength selection within the pump tuning range and locking of the idler wavelength with a stability of 1.7×10-3 cm-1 over at least 30 min.\ud \ud Using this approach, we locked the idler wavelength at an ethane absorption peak and obtained QEPAS data to verify the linear response of the QEPAS signal at different ethane concentrations (100 ppbv-20 ppmv) and different power levels. The detection limit for ethane was determined to be 13 ppbv (20 s averaging), corresponding to a normalized noise equivalent absorption coefficient of 4.4×10-7 cm-1  W/Hz1/2

Diode-laser Based Photo-acoustic Spectroscopy In Atmospheric No­2 Detection

We have developed a simple, low cost, and compact NO2 detection system. It\u27s based on photoacoustic spectroscopy (PAS) method uses a diode laser as a source of radiation. The PAS system has a detection limit of 10 ppbv for NO2. With this set-up we were able to detect the NO2 concentration from urban air near our campus. We have also investigated the NO2 dissociation effect on the PAS system via NO measurements using a direct absorption spectroscopy method on quantum cascade laser (QCL) system. Keywords: photoacoustic spectroscop

Liver enzymes are not directly involved in atrial fibrillation: a prospective cohort study

Background: Epidemiological evidence proposes the direct involvement of the liver enzymes in atrial fibrillation. These relationships are controversial and mechanistically unclear. As part of the British Regional Heart Study, we investigated whether change in liver enzymes over time associates with atrial fibrillation in men initially free of this heart condition. Materials and Methods: We prospectively investigated change (delta) in liver enzymes and new-onset atrial fibrillation in a representative sample of 1428 men aged 60-79 years. Results: Mean follow-up was 12.3 years, after which 108 new atrial fibrillation cases were identified. The liver enzymes did not differ at baseline or follow-up, except for gamma-glutamyl transferase which was higher at follow-up in men who developed atrial fibrillation compared to those who did not (P<0.0001). Change in GGT was greater in men who developed AF than those who did not (+6.12 vs. –2.60U/l, P=0.036). N-terminal pro-brain natriuretic peptide (baseline and follow-up, P<0.0001) and total bilirubin (follow-up only, P<0.0001) were also higher in men who developed atrial fibrillation while serum haemoglobin was similar at baseline and follow-up (P≥0.74). Atrial fibrillation was associated with change in gamma-glutamyl transferase (OR, 1.18; 95%CI, 1.01–1.37) after multiple adjustments and exclusions. However, after adjusting for baseline (P=0.088) or change (P=0.40) in N-terminal pro-brain natriuretic peptide, the association between atrial fibrillation and change in gamma-glutamyl transferase was lost. Conclusion: The direct relationship between atrial fibrillation and liver enzymes is absent and depends, at least in part, on the progression of heart failure as captured by N-terminal pro-brain natriuretic peptide