SESSION TYPE: COPD: Therapeutic Options
PRESENTED ON: Sunday, October 21, 2012 at 10:30 AM - 11:45 AM
PURPOSE: This study compares displacement of simulated airway mucus(mucus) treated with a combination of two osmolytes(isotonic saline solution[ISS, 3%] combined with sucrose solution[SS,2%]) to mucus treated with ISS(3%) or SS(2%) alone and control (not treated) inside a tracheal model during controlled coughs at low velocity.
METHODS: Simulated mucus similar in rheological properties to respiratory secretions of Chronic Obstructive Pulmonary Disease(COPD) patients(CHEST, 2010, 137:355-361), prepared using 0.01molar locust bean gum solution (Sigma, St Louis, MO) cross-linked with 12ml of sodium tetra-borate(0.02 molar) were nebulized with ISS(3%) or SS(2%) solutions or a combination of the two osmolytes (ISS[3%] and SS[2%]). Displacement of 0.3ml aliquots of all mucus (treated and untreated) were measured during coughs of 300ms at iso-velocity of 12±0.5m/s (low cough velocity of a typical adult COPD patient) ) generated using a computer controlled solenoid valve inside an inverted "D" shaped, horizontally oriented, Plexiglas model trachea (trachea, cross-sectional area =2.44cm^2).
RESULTS: Storage modulus (G’, a measure of elasticity) of mucus was decreased significantly (p<0.0001, GLMM) by sucrose solution but was increased by ISS solution compared to control (untreated). Both osmolytes(ISS, SS) and the combination of osmolytes did not alter the viscosity of mucus significantly. Combination of the two osmolytes resulted in an optimum G’ which increased displacement significantly(p<0.0001, GLMM) during cough compared to mucus treated with either osmolyte alone or control.
CONCLUSIONS: Treating mucus with isotonic saline solution(3%) combined with sucrose solution(2%) is more effective in enhancing displacement inside trachea during cough at low cough velocity compared to treating mucus with ISS(3%) or SS(2%) alone or untreated.
CLINICAL IMPLICATIONS: Mucus requires an optimum value of storage modulus for clearance by cough. Excess elasticity may decrease mucus transportability while inadequate elasticity may reduce transfer of kinetic energy to mucus from cough airflow. Osmolytes may increase or decrease elasticity of mucus. Combined use of osmolytes in appropriate amount may be effective in hydrating mucus thereby promoting mucus clearance during cough in COPD patients with low velocities of cough.
DISCLOSURE: The following authors have nothing to disclose: Anpalaki Ragavan, Cahit Evrensel, Peter Krumpe
No Product/Research Disclosure InformationUniversity of Nevada, Reno, Reno, NV