P131 Fitness to fly assessment in patients with neuromuscular disease

Abstract

measure of gas mixing, Lung Clearance Index (LCI), derived from multiple breath washouts using sulphur hexafluoride as tracer gas and a modified Innocor gas analyser, to detect early airway changes in smokers with normal spirometry. Methods Current cigarette smokers with a smoking history of over 10 pack years and no known cardiac or respiratory disease were recruited from smoking cessation clinics. Spirometry was performed to ERS standards before and after salbutamol. Participants with post-bronchodilator FEV 1 <80% predicted, FEV 1 /FVC<0.7, or a significant bronchodilator response were excluded from analysis. St George's Respiratory Questionnaire (SGRQ) was completed. LCI reported is the mean of at least two technically acceptable repeat measurements.Results 17 participants remained after exclusions, mean age 44 years (range 31e57) and mean smoking history of 25 pack years (range 11e60). Mean (SD) post-bronchodilator FEV 1 and FEF 25e75 was 101 (12) and 80 (23)% predicted respectively. Only one participant had FEF 25e75 <60%. There was a moderate negative correlation between smoking history and FEF 25e75 (r¼À0.51, p¼0.037) but not between smoking history and FEV 1 . Mean (SD) LCI was 7.7 (0.98) with mean (SD) intra-visit coefficient of variation of 3.7 (2.5)%. Eight participants had LCI>7.5 (95% CI for LCI in normal subjects 5.9e7.5), suggesting impaired lung gas mixing. There was a negative correlation between LCI and FEV 1 (r¼À0.55, p¼0.02) and between LCI and FEF 25e75 (r¼À0.66, p¼0.004) but no significant correlation between LCI and smoking history or total SGRQ score. Mean (SD) total SGRQ score was 10.9 (7.5), 12 participants scoring over 7 (95% CI for total SGRQ score in normal subjects 5e7). Total SGRQ did not correlate with smoking history, LCI, FEV 1 or FEF 25e75 . Conclusions These data support the hypothesis that LCI is a sensitive marker of early airway changes in smokers with normal FEV 1 and FEF 25e75 . The effects of smoking cessation on this measure are currently being investigated. Background Differences in peak expiratory flow (PEF) in children have been shown using a short exhalation PEF compared with a forced vital capacity (FVC) manoeuvre, when measured by turbine spirometry. Furthermore, PEF measures using a traditional Wright's scale PEF metre have been compared with those measured by FVC using a pneumotachograph in adults. The traditional Wright's scale may give rise to misleading results in children, and as such universal adoption of the EU scale has been advocated in the UK. To our knowledge, no study has compared PEF measured using a miniWright's EU scale PEF metre and PEF measured by FVC manoeuvres using a pneumotachograph in children. Methods A retrospective review of children attending asthma clinic at a tertiary paediatric asthma clinic were carried out. Children underwent spirometry (Jaeger Masterscreen PFT Pro) using a pneumotachograph in accordance with ATS/ERS guidelines. In addition, peak expiratory flow (PEF) using a mini-Wright's PEF metre (Clement-Clarke International) w...

BTS Clinical Statement on air travel for passengers with respiratory disease

“…Despite the small numbers, none of the patients with an MIP >30 mm Hg or with sea level SpO2 >96% desaturated below 85% during HCT. Preliminary data from a smaller study of 12 patients with MND suggested that sniff nasal inspiratory pressure (SNIP) may more accurately predict the risk of hypoxia during air travel in those with neuromuscular disease and respiratory muscle weakness 127…”

“…Preliminary data from a smaller study of 12 patients with MND suggested that sniff nasal inspiratory pressure (SNIP) may more accurately predict the risk of hypoxia during air travel in those with neuromuscular disease and respiratory muscle weakness. 127 While evidence to date addresses specific patient groups, the principles may be applied to any individual with a restrictive disorder resulting from respiratory muscle weakness or chest wall deformity. Further research on the value of FVC, PaCO2, MIP and/or SNIP in predicting HCT outcome in this group is desirable.…”