Sodium cromoglycate and eformoterol attenuate sensitivity and reactivity to inhaled mannitol in subjects with bronchiectasis.

BACKGROUND AND OBJECTIVE: Dry powder mannitol has the potential to be used to enhance clearance of mucus in subjects with bronchiectasis. A reduction in FEV1 has been recorded in some subjects with bronchiectasis after inhaling mannitol. The aim of this study was to investigate if pre-medicating with either sodium cromoglycate (SCG) or eformoterol could inhibit this reduction in FEV1. METHODS: A double-blind, placebo-controlled, randomized cross-over study was conducted. Lung function and airway response to mannitol was assessed on a control day and then re-assessed after pre-medication with placebo, SCG and eformoterol in nine subjects. Sensitivity to mannitol, expressed as the dose required to induce a 15% fall in FEV1 (PD15), and reactivity to mannitol, expressed as the % fall in FEV1 per mg of mannitol (response-dose ratio, RDR), are reported. RESULTS: Subjects had an FEV1 of 68 ± 14% predicted, FVC of 97 ± 15% predicted and FEV1 /FVC of 71 ± 8%. They were mildly hypoxemic and the SpO2 was 95 ± 2%.They had a PD15 to mannitol of 235 mg (95% CI: 150-368 mg) and a RDR of 0.057% fall in FEV1 per mg (95% CI: 0.038-0.085). After pre-medication with SCG, PD15 increased (773 mg, P < 0.05) and RDR was reduced (0.013, P < 0.05). Pre-medication with eformoterol also resulted in an increased PD15 (1141 mg, P < 0.01) and a reduced RDR (0.009, P < 0.01). A small but significant decrease in SpO2 from baseline was noted after mannitol in the presence of SCG (P < 0.05). CONCLUSIONS: Pre-medication with either SCG or eformoterol protects patients with bronchiectasis from developing a significant reduction in FEV1 after inhaling mannitol.

Inhaled mannitol for the treatment of mucociliary dysfunction in patients with bronchiectasis: effect on lung function, health status and sputum.

OBJECTIVE: Inhaled mannitol increases mucus clearance in patients with bronchiectasis by an unclear mechanism. The effect of mannitol on lung function, health status and sputum properties was investigated. METHODOLOGY: Nine patients with bronchiectasis inhaled 400 mg of mannitol once daily for 12 days. Health status was assessed using the St George's Respiratory Questionnaire (SGRQ). Sputum was analysed for viscosity, elasticity, spinnability, surface tension, contact angle, solids, mucociliary transportability (MCTR) on a frog palate, and cough transportability (CTR) on a simulated cough machine. RESULTS: Lung function was unchanged with treatment (baseline FEV1 82.0 +/- 16.2%) apart from an improvement in FEF from 85.4 +/- 13% (baseline) to 90.7 +/- 14.4% (P < 0.05; 12th treatment; visit 7). The total SGRQ score (mean +/- SD) of 49.3 +/- 13.8 at baseline, decreased by 12.4 +/- 10.2 (P < 0.01; visit 7) and 10.1 +/- 9.4 units (P < 0.02) 6-10 days after treatment cessation. The baseline subscores for symptoms (72.9 +/- 11.8), activity (44.7 +/- 20.9) and impact (44.4 +/- 14.3) were reduced by 0.8 +/- 9.1 (P > 0.7), 8.4 +/- 16.0 (P > 0.1) and 19.2 +/- 13.7 (P < 0.005) units, respectively (visit 7). Mannitol reduced the baseline (mean +/- SE) surface tension from 94.5 +/- 1.4 to 84.7 +/- 2.1 mN/m (P < 0.0001), contact angle from 51.1 +/- 2.8 to 33.2 +/- 2.4 degrees (P < 0.0001), spinnability from 11.6 +/- 0.4 to 10.0 +/- 0.2 mm (P < 0.005), and solids from 5.7 +/- 0.4 to 4.3 +/- 0.7% (P < 0.02), acutely (visit 7). Viscosity, elasticity and MCTR did not change significantly, while CTR was increased from 25.8 +/- 1.0 to 34.1 +/- 2.7 mm (P < 0.003). CONCLUSION: Mannitol significantly improved the health status over 12 days and this improvement was maintained for 6-10 days after cessation of treatment. In addition, mannitol reduced the tenacity, increased the hydration of mucus acutely and improved cough clearability in patients with bronchiectasis.