Lung Expansion Therapy and Airway Clearance Therapy

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Lung expansion therapy is used to prevent or reverse atelectasis, by helping patients achieve and maintain lung function. Untreated atelectasis can cause pulmonary shunting, hypoxemia, and even respiratory failure. Factors associated with the development of atelectasis include prolonged bed rest (especially in the supine position) or immobilization, heavy sedation, surgery or trauma near the diaphragm, and increased intraabdominal pressure. Some of the devices used in lung expansion therapy include incentive spirometers, intermittent positive-pressure breathing (IPPB) devices, chest wall percussors and high-frequency oscillation devices1. When selecting a device, the RT must be aware of the patient’s health and physical status, present clinical conditions, therapy devices and goals. For example, aging can influence the lung’s physiology and function by reducing elastic recoil, compliance, and strength of respiratory muscles. Research has found that in elderly patients, flow incentive spirometry (FIS) and volume incentive spirometry (VIS) both increased the chest wall volumes but increased inspiratory muscle activity was needed for the successful use of FIS. In healthy, younger adults, VIS increased chest wall volumes more than FIS but this population was not affected by the increased inspiratory muscle activity needed for FIS2.

The physiology of the airway clearance mechanism can be disrupted by abnormalities found in the ciliary structure, patency of the airway, the amount and thickness of secretions, the cough reflex, and breathing strength. Certain diseases such as cystic fibrosis, bronchiectasis, lung cancer, and muscular dystrophy, can be associated with abnormal airway clearance. Some of the devices used to prevent secretion retention include chest physical therapy, coughing and related expulsion techniques, positive airway pressure (PAP) adjuncts, high-frequency compressions and oscillations, and mobilization and exercise. When selecting the appropriate technique, the RT must be aware of the patient’s current health status, cooperation level, clinical conditions, and age. For example, patients suffering from musculotskeletal weakness may benefit from mechanical insufflation-exsufflation (MIE) and PEP techniques. The MIE device provides 30 to 50 cm H2O of positive pressure to the airway for approximately 1 to 3 seconds. Then the pressure is reversed to -30 to -50 cm H2O. Treatment includes 5 cycles of MIE, which is then followed by normal spontaneous breathing3.

PEP therapy creates positive airway pressure and is used to clear secretions. This device requires active expiration against a variable flow resistance. The positive pressure will help prevent the airways from collapsing while moving the secretions into the larger airways through collateral ventilation. The advantages of using this device is that it can be self-administered and is relatively inexpensive but would not be recommended for children less than 3 years of age due to the expiratory requirements3.

References:

 

  1. Cairo JM. Lung Expansion Therapy Devices. In: Mosby’s Respiratory Care Equipment, 9th edition Elsevier; 2014:213-216.
  2. Lunardi AC, Porras DC, Barbosa RC, Paisani DM, Marques da Silva CC, Tanaka C, et al. Effect of Volume-Oriented Versus Flow-Oriented Incentive Spirometry on Chest Wall Volumes, Inspiratory Muscle Activity, and Thoracoabdominal Synchrony in the Elderly. Respiratory Care 2014; 59(3):420-426.
  3. Hirsch C, Kacmarek R, M., Stoller J, Heur A. Airway Clearance Therapy. In: Egan’s Fundamentals of Respiratory Care, 10th edition Elsevier; 2013:962-986.

 

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