Use of the Lung Flute for sputum induction in children with cystic fibrosis: a pilot study

This study aimed to assess the effectiveness of the Lung Flute in obtaining a sputum sample from children with cystic fibrosis (CF) that were not productive of sputum with coughing alone. Children attending an outpatient CF clinic who were not able to provide a sample with coughing alone were eligible. Each child used the Lung Flute on two occasions at least one month apart. The primary outcome was expectoration of a sputum sample. Secondary outcomes were sputum microbiology, time taken for the procedure, and ease of use of the device as assessed by the patient using a visual analogue scale (VAS), with 0/10 representing very easy and 10/10 representing very hard. Twenty-five children participated (15 males, mean age 12.7 range 6.5-17.9). Overall, a sputum sample was obtained on 26/50 (52%) uses of the device. In children that presented with a moist cough, a sample was obtained on 17/17 (100%) occasions, compared to 9/33 (27%) occasions when a child presented with a dry cough. A positive culture result for at least one known CF pathogen was found in 24/26 samples. Culture results from obtained samples resulted in management changes in 12 cases. Mean time taken to obtain a sample was 9.8 min (SD 2.2). Mean ease of use on the VAS was 1.5 (SD 1.6).

Conclusion: The lung flute appears to be a clinically useful and easy device for sputum induction in children with CF. Further research comparing its effectiveness to other sputum induction methods is warranted.