Sputum viscosity

Airway clearance therapy is usually accompanied by bron-chodilator treatment [albuterol (also known as salbutamol outside the United States) by nebulizer or metered-dose inhaler] to stimulate mucociliary clearance and prevent bronchospasm associated with other inhaled agents. A mucolytic agent may be administered to reduce sputum viscosity and enhance clearance. 

Q33 In cough, which of the following constituents is used to reduce sputum viscosity ... 

Carbocisteine is classified as a mucolytic as it reduces sputum viscosity and aids its elimination. Carbocisteine is therefore indicated for use in chesty cough. Pholcodine, dextromethorphan and the sedating antihistamines, such... 

Retention of viscous purulent secretions, which contain high concentrations of extracellular DNA—released by degenerating leukocytes that accumulate in response to infection [24]—in the airways contributes both to reduced pulmonary function and to exacerbations of infection [24,25], Digestion of DNA polymers in purulent secretion with DNAse (dornase-a or Pulmozyme) has been shown to reduce sputum viscosity in cystic fibrosis patients. The availability of recombinant DNAse has allowed its use in an aerosol formulation to deliver the enzyme into the deep lung alveoli of CF patients. The purihed glycoprotein contains 260 amino acids with an approximate molecular weight of 37,000 daltons [26], The primary amino-acid sequence is identical to that of the... 

P. L. Shah, S. Scott, A. Laiulcy, G. Martin, C. Marriott, and M. E. Hodson. Preliminary report on in vivo reduction of sputum viscosity in cystic fibrosis patients treated... 

Water inhalation as an aerosol (breathing over a hot basin), though cheap, is not to be despised, and is good expectorant therapy in bronchiectasis. Simply hydrating a dehydrated patient can have a beneficial effect in lowering sputum viscosity. 

Bromhexine is taken orally or by aerosol and reduces sputum viscosity as measured ex vivo. Although it is still used empirically by some physicians, there have been no controlled studies showing a significant improvement in clinical status or lung function. Administration by inhalation aerosol or nasal spray produces a local expectorant/ mucolytic effect (1). Inhaled bromhexine (Paxirasol) reduces the amount of sputum, but does not reduce symptoms (SEDA-17, 208). 

Mucolytlcs - The problems presented by thick, tenacious sputum are central to the treatment of chronic bronchitis. There Is an Important need for effective mucolytlcs, particularly orally effective congiounds. The mucolytic-expectorant bromhexine (I), N-cyclohexyl-N-methyl-(2-amlno-3,5-dlbromobenzyl)ammonium chloride, was shown earlier to fragment the acid mucopolysaccharide fibers In sputum, thereby decreasing sputum viscosity. 

These findings have been corroborated by the study of Bruce Kumar fdio examined oral effectiveness (8 mg t.l.d.) over a ten day period in 5 normal subjects with uninfected sputum. Marked fragmentation of the acid mucopolysaccharide fibers and decreased sputum viscosity occurred by the end of the treatment period, followed five days later by return to control levels or above. 

Secretion clearance is addressed in detail elsewhere in the text. However, physical therapy and careful hydration are the cornerstones of management. Mucupurulent secretions are often noted in acute respiratory failure. Administration of acetylcysteine 600 mg/day will decrease sputum viscosity hut its value in NIV patients has been less well studied. In patients with NMD, manually assisted coughing, air stacking, and mechanical devices can all be used in patients with a facial mask. On rare occasions, bronchial lavage under local anesthesia can be carried out during NIV. Secretion clearance reduces the ventilation pressures required to overcome the impedance to airflow. 

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