Peak cough flow in children with neuromuscular diseases

Patients with neuromuscular diseases (NMDs) present with reduced cough effectiveness due to progressive weakness of respiratory muscles leading to respiratory complications. When weakness or incompetence of these muscles is present, there is a reduction in the peak flow rate (PCF) value during coughing and consequently, a reduction in the effectiveness of the cough itself. PCF is the most reliable measure that allows us, through a simple maneuver, to verify the expulsive capacity of the cough act.  In adult patients with NMD, numerous studies have been conducted to determine the cough peak cut-off measures used to identify patients in need of cough assistance techniques. 
These studies have determined that normal PCF values in adults are greater than 360-400 L/min while individuals with peak cough values less than 270 L/min fall into the category at increased risk of complications during respiratory infections. Therefore, it is well known that the cut-off for the initiation of rehabilitation programs involving cough assist devices is a PCF below 270 L/min. This scale of values has also been incorporated into the assessment of cough quality in the pediatric population under 10 years of age.  In order to be able to confirm the appropriateness of these indications and derive pediatric-specific reference values, further and more specific studies are increasingly needed.

Bibliography

Kotwal, Nidhi et al. “Peak Cough Flow in Children with Neuromuscular Disorders.” Lung vol. 198,2 (2020): 371-375. doi:10.1007/s00408-020-00340-