Cough in Neuromuscular Disease
Note: The content on this page or elsewhere on this website should not be used as a substitute for medical care.  For medical care or advice, please seek the care of a clinician who specializes in the breathing issues of those with Neuromuscular Disease (NMD).

One of the key components to the management of neuromuscular breathing weakness is cough augmentation, making a cough stronger.  Those with weakened breathing muscles can have cough insufficiency, preventing the individual from having a strong and/or effective cough, one that fails to bring secretions (mucus) and/or inhaled dust, food, or liquid up and out of the airways. 
 
Your Neuromuscular Disease (NMD) care team should develop a plan for cough augmentation and secretion (mucus) clearance before you are in emergent need of it. This helps to improve quality of life and prolong life. Periodic evaluation of cough strength can ensure this therapy is started, the equipment is ordered and delivered, and the individual and/or caregivers are trained and experienced in how to use it before it is urgently needed. 

Peak expiratory cough flow, a measure that your neuromuscular breathing specialist can obtain during checkups, is typically used to determine when to start cough augmentation therapy. A peak expiratory cough flow of 160 L/min or less is the typical threshold, but individuals with a peak expiratory cough flow of 270 L/min are considered at risk for complications associated with a respiratory infection because their cough strength can weaken further during infection. Having a maximum or “peak” expiratory pressure of 60 cm H2O or a history of repeated hospitalizations for respiratory infection and an inability to cough to effectively clear secretions are also indicators that it is time for an individual with NMD to start cough augmentation therapy in the home.
 
Effective secretion clearance can prevent atelectasis, a condition where tiny air sacs, “alveoli” within the lung collapse, pneumonia, acute respiratory failure, and hospitalization which can lead to poor outcomes. Options for making a weak and/or ineffective cough stronger and clearing secretions from the airways include manual cough assistance, use of a modified Ambu bag/manual resuscitator to deliver a stronger breath that more fully fills the lungs, and mechanical cough assistance.

​Most with NMD find mechanical cough assistance to be the most effective and often can be done independently. You may hear or see the terms “mechanically assisted cough (MAC),” “insufflation/exsufflation” or “cough assist” all used to describe the most commonly used mechanical form of cough augmentation in the United States (US). 
 
How does mechanical cough assistance work?  It delivers through an oronasal mask, a mouthpiece, or a translaryngeal or tracheostomy tube, a large positive pressure breath of air at a specified speed (insufflation).  After the lungs expand, the device reverses the flow of air at a specified speed to deliver a negative pressure breath (exsufflation).  This simulates a stronger cough, pushing secretions up and out of the airways. Note: Your respiratory care company may provide the device without the mouthpiece unless your physician requests it in their order.  Individuals who use the mouthpiece must have the ability to form and hold a lip seal on the mouthpiece.  Those without bulbar muscle weakness are good candidates for mouthpiece cough assistance.
 
Why use mechanical cough assistance versus suction?
The left main stem bronchus of the lungs can be easily missed in invasive airway suctioning.  Mechanical cough assistance can clear both left and right airways. Many individuals also find it less uncomfortable than suctioning.  In addition to those who use invasive ventilation via tracheostomy tubes, some who use noninvasive ventilation also use a portable suction device in addition to their mechanical cough device.  Mechanical cough assistance can bring secretions out of the airways and deposit them into the mouth.  When the secretions are thick, sticky, and difficult to remove from the mouth, a suction machine can be used with a yankauer suction tip.

Other Options for Airway Clearance
The Intermittent Percussive Ventilation (IPV®) device and the Metaneb® System (Hill-Rom, Inc.), are other options for airway clearance in addition to using cough assistance (manual or mechanical) and a suction machine with a yankauer suction tip. Loosening secretions stuck in the outer areas, the periphery of the lungs, may be easier with the IPV or Metaneb as these loosen mucus from the outer pulmonary areas, bringing it into the central airway where a mechanical cough assistance machine begins its work. Finally, a suction machine can complete the last step of secretion removal. All three steps are essential for some individuals, particularly those with bulbar muscle weakness who find using mechanical cough assistance alone may be extremely fatiguing.  
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Reference:
The following includes additional details about cough in NMD that you may want to review.
Resources for Philips Respironics CoughAssist T70:
Resources for Baxter/Hillrom/Welch Allyn Devices: ​
ABM Respiratory Care BiWaze Cough System: 
Blog Posts on Mechanical Cough Assistance: The Device You Love to Hate: https://breathewithmd.org/ask-andrea/the-device-you-love-to-hate​