Timing of hypertonic saline inhalation for cystic fibrosis

Inhalation of hypertonic saline improves sputum rheology, accelerates mucociliary clearance and improves clinical outcomes of people with cystic fibrosis.

To determine whether the timing of hypertonic saline inhalation (in relation to airway clearance techniques or in relation to time of day) has an impact on its clinical efficacy in people with cystic fibrosis.

We identified relevant randomised and quasi-randomised controlled trials from the Cochrane Cystic Fibrosis Trials Register, the Physiotherapy Evidence Database (PEDro), and international cystic fibrosis conference proceedings.Date of the last search of the Group's Cystic Fibrosis Trials Register: 6 December 2011.

Any trial of hypertonic saline in people with cystic fibrosis where timing of inhalation was the randomised element in the study protocol with either: inhalation up to six hours before airway clearance techniques compared to inhalation during airway clearance techniques compared to inhalation up to six hours after airway clearance techniques; or morning compared to evening inhalation with any definition provided by the author.

Both authors independently assessed the trials identified by the search for potential inclusion in the review.

The search strategy identified 50 trial reports which represented 24 unique studies. One study, published only as an abstract, is awaiting further assessment. None of the other studies compared timing regimens for the inhalation of hypertonic saline and we excluded these from the review.

This review did not identify any evidence comparing the timing of hypertonic saline inhalation in relation to airway clearance physiotherapy. Until such evidence becomes available, clinicians could advise patients to inhale hypertonic saline before airway clearance, because this is the only regimen evaluated in the studies that established the efficacy of the use of hypertonic saline. This review also did not identify any evidence comparing the timing of hypertonic saline inhalation in relation to time of day. Until such evidence becomes available, clinicians could advise patients to inhale hypertonic saline morning and evening; but if only one dose per day is tolerated, the time of day at which it is inhaled could be based on convenience or tolerability.Given the competing theoretical rationales about why hypertonic saline could be more effective if inhaled at certain times, a trial comparing these various timing regimens should be conducted.