Emma E. Wilson

The utility of exhaled nitric oxide in patients with suspected asthma

The value of FENO measurements in patients with symptoms suggestive of asthma is unclear. We performed an observational study to assess the ability of FENO to diagnose asthma and to predict response to inhaled corticosteroids (ICS). Our findings suggest FENO is not useful for asthma diagnosis but is accurate at predicting ICS response.

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.

Untargeted metabolic profiling of saliva by liquid chromatography-mass spectrometry for the identification of potential diagnostic biomarkers of asthma

Current clinical tests employed to diagnose asthma are inaccurate and limited by their invasive nature. New metabolite profiling technologies offer an opportunity to improve asthma diagnosis using non-invasive sampling. A rapid analytical method for metabolite profiling of saliva is reported using ultra-high performance liquid chromatography combined with high resolution time-of-flight mass spectrometry (UHPLC-MS). The only sample pre-treatment required was protein precipitation with acetonitrile. The method has been applied to a pilot study of saliva samples obtained by passive drool from well phenotyped patients with asthma and healthy controls. Stepwise data reduction and multivariate statistical analysis was performed on the complex dataset obtained from the UHPLC-MS analysis to identify potential metabolomic biomarkers of asthma in saliva. Ten discriminant features were identified that distinguished between moderate asthma and healthy control samples with an overall recognition ability of 80% during training of the model and 97% for model cross-validation. The reported method demonstrates the potential for a non-invasive approach to the clinical diagnosis of asthma using mass spectrometry-based metabolic profiling of saliva.

Exhaled nitric oxide and inhaled corticosteroid dose reduction in asthma: a cohort study

To the Editor: Inhaled corticosteroids (ICS) reduce airway inflammation; however, guidelines recommend titrating ICS dose based on symptoms [1], which are not closely associated with airway inflammation [2]. Once symptoms are controlled for ≥3 months, ICS reduction is recommended [3] but step-down is often not implemented. Studies suggest that the majority of patients treated with ICS can have their therapy stepped down, although there is no clear evidence on how best to achieve this [4]. We assessed whether exhaled nitric oxide fraction ( F eNO) measurements could predict a loss of symptom control or exacerbation following a reduction in ICS dose in a cohort study of people with well-controlled asthma recruited from primary care. All participants had a recorded asthma diagnosis, were aged 18–75 years, and had received at least one ICS prescription in the last year. The study was restricted to nonsmokers ( 1.5 at visit 1 (indicating poor control) were excluded. Participants were seen at the same time of day on four occasions: days 0, 14, 21 and 110. At each visit, ACQ-5, F eNO (Flex Flow; Aerocrine, Solna, Sweden) and spirometry were performed. Symptoms were assessed using the ACQ-5 [6]. Airway inflammation was measured using F eNO at 50 mL·s−1; participants were blinded to their measurements. Differential …