Hypertonic Saline

Hypertonic saline is a mucus-thinning agent often prescribed for patients with cystic fibrosis (CF). It is a solution of sodium chloride (a common salt) at concentrations greater than physiological concentrations. (Blood and tissues have a salt concentration of about 0.9 percent).

Available in several concentrations, hypertonic saline is taken by CF patients as a mist using a nebulizer, usually several times per day. 

How hypertonic saline helps CF patients

CF is a chronic, inherited condition caused by mutations in the CFTR gene, which encodes for a protein that channels salt across cell membranes. Mutations in the gene cause the CFTR protein not to function properly and lead to salt not being trafficked normally. This, in turn, produces a buildup of thick sticky mucus in different organs and tissues. In the lungs, this mucus causes obstructions and difficulty breathing, making patients more susceptible to infections.

Hypertonic saline draws water out of epithelial tissue through osmosis, thinning the mucus and making it easier to cough up. The charged particles of the solution can also help break up the mucus, and prevent infections from gaining a foothold in the lungs.

Hypertonic saline in clinical trials for CF

A review article published in the Cochrane Database of Systematic Reviews examined the results of 19 clinical studies assessing hypertonic saline as a therapy for CF. The trials included 966 patients in total, from 4 months to 64 years old.

It concluded that regular use of hypertonic saline by CF patients over 12 results in a mild improvement in lung function at four weeks as measured by forced expiratory volume in 1 second (FEV1, or the volume of air that a patient can breathe out in 1 second). However, this improvement was very mild and not visible at later points in the studies.

The review also found that hypertonic saline reduced the frequency of pulmonary exacerbations (severe lung infections that reduce lung capacity) in patients over age 6, and may improve quality of life.

Other information

Because hypertonic saline is a simple salt solution, many patients are tempted to prepare their own but this is not recommended as the solution wouldn’t be sterile and may be a source of lung infections. 

Many patients experience cough, tightness in the chest, and sore throat following the administration of hypertonic saline.


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