The authors respond to: CPAP in cystic fibrosis: is it time to surrender yet?

Measuring the efficacy of one airway clearance technique over another is still challenging and sometimes frustrating in an evidence-based era. We want our patients clear and intuitively we assume that what they expectorate is what we have really cleared. As Sirens caught Ulysses along his journey, respiratory therapists and physiotherapists are often tempted to believe that sputum is the best available end point of any treatment. Despite this, patients use sputum output to measure the relative effectiveness of different airway clearance regimens1 and patients’ preferences continue to be a factor when introducing an airway clearance technique.2 The paper by Aquino and colleagues in the November issue of RESPIRATORY CARE3 evaluated if CPAP increases the effects of hypertonic saline on mucus clearance, sputum physical properties and expectoration in patients with cystic fibrosis (CF). Their crossover study randomized 15 patients to CPAP alone or CPAP followed by hypertonic saline aerosol. Direct cough was standardized as a series of 3 coughs on command and used as control intervention. Relying on outcome measures such as sputum volume, clearability, and wettability, Aquino et al concluded that CPAP alone did not improve sputum clearance or augment the effect of hypertonic saline. As respiratory therapists and physiotherapists involved in the care of patients with CF, we want to highlight 2 crucial points and report our experience, for a better interpretation of the results.