Cic edizioni internazionali
Shortness of Breath

Management of cough ineffectiveness in neuromuscular disorders

Mini-Review, 28 - 34
doi: 10.11138/sob/2013.2.1.028
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Cough is a vital function for eliminating excess secretions and foreign particles from the airways. An ineffective cough becomes clinically important in patients with disorders of the airways and/or weakness of respiratory muscles, significantly increasing the risk of acute respiratory failure due to mucus accumulation. The choice of the most appropriate treatment for clearing secretions must be carefully evaluated since some techniques target mainly the peripheral, while others the central airways.
In patients suffering from muscular weakness, the latter techniques are preferred because they enhance elastic recoil of the thoracic wall and increase expiratory (cough) flow. In normal subjects, the peak cough flow (PCF) varies from 360 to 1200 L/min. A PCF of at least 270 L/min is necessary to effectively expel secretions; below 160 L/min, the cough is very ineffective. Mechanically assisted coughing (MAC) can become vital to avert acute respiratory failure (ARF).
The history of mechanical insufflation-exsufflation (MI-E) goes back to 1951 with Dr. Alvin Barach adapting a device to provide MI-E via an iron lung valve to create sudden intratank positive pressure after maximum negative intratank pressure to cause
a forced lung exsufflation. In 1952 the MI-E was first applied via an oronasal interface. Initially called a Cof-flator (OEM Company, Norwalk, Connecticut) these devices that provide MI-E went off the marked in the late 1960s but came available again in February of 1992 as clinicians turned away from invasive to more noninvasive respiratory management. Mechanically assisted coughing using this device can in conjunction with an exsufflation-timed abdominal thrust can prevent respiratory insufficiency caused by bronchial mucus retention in neuromuscular disease, reduce the time required to wean from invasive mechanical ventilation, and allows for decannulation of patients with tracheostomy tubes. At present,
guidelines for managing neuromuscular disorders include MAC with specific indications for both adult and paediatric patients.