The main cause of respiratory difficulties in polio survivors is the inability to take a deep breath due to weakness of the respiratory muscles and to cough effectively to clear secretions and mucus plugs. The lack of a good cough can lead to further pulmonary complications such as pneumonia (including aspiration pneumonia) and respiratory insufficiency.
If an individual’s cough is weak (less than 4.5 L [liters] per sec), the onset of a cold must be dealt with as a serious and potentially life-threatening situation. Manually-assisted coughing techniques can provide deep breaths to augment cough flows. Techniques include postural drainage, percussion, and abdominal thrusts administered by a therapist or a caregiver who places their hands on the individual’s abdomen and delivers thrusts timed just before the person coughs. For an adult with less than 1.5 L of vital capacity, the individual should be given the greatest volume of air that he or she can hold in the lungs, either with an Ambu bag or volume ventilator, before the thrust (Bach, 1996). Mechanically-assisted coughing involves using a device such as a CoughAssist device which applies a positive pressure to the airway and then rapidly shifts to negative pressure to expel mucus out of the airway.
Reference
Bach, J.R. (1996). Pulmonary rehabilitation: The obstructive and paralytic conditions. Philadelphia, PA: Hanley & Belfus, Inc.