Effects of the Cornet Device on Mucus Clearance: A Narrative Review

Abstract

Background: Impaired mucociliary clearance is a hallmark of chronic respiratory diseases such as cystic fibrosis (CF), non-CF bronchiectasis, and chronic obstructive pulmonary disease (COPD), leading to recurrent infection, airway damage, and reduced quality of life. The RC-Cornet (CEGLA Medizintechnik, Montabaur, Germany) is a handheld oscillating positive expiratory pressure (OPEP) device designed to mobilise and facilitate expectoration of bronchial secretions.
Objective: To critically appraise the design, proposed mechanism of action, and device-specific clinical evidence for the RC-Cornet, and to distinguish this evidence from that concerning oscillating PEP devices and airway clearance techniques (ACTs) more broadly.
Methods: A structured narrative review was conducted, following a pre-specified search strategy across PubMed/MEDLINE, Embase, the Cochrane Library, and Physiotherapy Evidence Database (PEDro), supplemented by hand-searching of reference lists and relevant clinical guidelines. Only peer-reviewed, indexed sources were used as primary evidence; non-scholarly and unindexed web sources were excluded.
Results: Device-specific evidence for the RC-Cornet consists predominantly of small randomised and crossover trials (mainly in COPD, from a single German research group), conference abstracts, and case reports, with no adequately powered, placebo-controlled trial isolating hard clinical outcomes. The device appears to reduce airway resistance and improve markers of sputum mobilisation acutely, and one small trial suggests it may enhance the bronchodilating effect of nebulised ipratropium bromide, but confirmatory replication is lacking.
Conclusion: The RC-Cornet is a plausible, low-cost, portable adjunct for airway clearance in patients with hypersecretory respiratory disease. However, the evidence base specific to this device remains limited in volume, methodological rigour, and generalisability. Claims of efficacy, safety, cost-effectiveness, and bronchodilator synergy should be regarded as hypothesis-generating rather than established, pending larger, adequately powered, and ideally sham-controlled trials with clinically meaningful endpoints.