SUPPORTING TECHNIQUES

In-Exsufflator (Cough Machine): a device which may assist in the removal of bronchial secretions
(CE mark obtained in Dec. 2000 in cooperation with some branches of UILDM – the Italian Muscular Dystrophy Association. Trade and sale is now allowed in the countries of the European Community). For further details on the machine: http://www.jhermerson.com
 

In adults, at least 10,000 L of air per day expose airway membranes to toxic gases, dust and microorganisms, some of which are deposited in the lower airways. Effective defense mechanisms are, therefore, required to clear the airways of foreign matter and to keep the lungs sterile. One of the most important lung defense mechanism is the production of bronchial secretions, or mucus.

Mucus is produced throughout the bronchial tree: the amount of mucus produced at any level in the bronchial tree depends on the number of mucus-producing cells and to the number of these cells related to the total airway surface. Airway surface decreases from the peripheral to the central airways.

Forced expirations and coughing are probably the most effective aspects of "chest physical therapy" for improving mucus transport, to facilitate airway secretion elimination and thereby improve respiratory symptoms and prevent complications.

A normal cough, however, requires a pre-cough inspiration or insufflation. Unfortunately, the inspiratory muscles of people with neuromuscular diseases are often too weak to provide a deep breath. Likewise, weak espiratory muscles may fail to generate sufficient pressure to create flows that can expel bronchial secretions. This is why ventilator users with neuromuscular disorders and their family should be taught both manually assisted and mechanically assisted coughing.

Manually assisted coughing
Techniques of manually assisted coughing involve different hand and arm placements for expiratory cycle thrusts. Manually assisted coughing requires a cooperative patient, good coordination between the patient and the caregiver, and adequate physical effort and often frequent application by the caregiver. It is usually ineffective in the presence of significant scoliosis.
 
Mechanically assisted coughing
In February of 1993, the In-Exsufflator came onto the market. This manual or automatic cycling feature facilitates caregiver-patient coordination of inspiration and expiration with insufflation and exsufflation but requires and additional hand for an abdominal thrust or if one hand is inadequate to affix the mask. One treatment consists of about five cycles if inspiration-expiration followed by a period of normal breathing or ventilator use for 20 to 30 seconds to avoid hyperventilation. Five or more treatments are given in one sitting and the treatments are repeated until no further secretions are expulsed.

The efficacy of In-Exsufflator was demonstrated both clinically and on animal models. In over 650 patient-years and hundreds of applications of In-Exsufflator by USA neuromuscular ventilator users, no episodes of pneumothorax, aspiration of gastric contents, or blood-streaking of sputum were observed. Borborygmus and abdominal distension are infrequent and eliminated by decreasing insufflation pressures below the patient’s inspiratory reserve volume.

Bibliography
  • John R. Bach – Pulmonary Rehabilitation – The Obstructive and Paralytic Conditions – 1996 Hanley&Belfus, Inc.
  • John R. Bach – Guide to the Evaluation and Management of Neuromuscular Disease – 1999 Hanley&Belfus, Inc.
  • John R. Bach – Secretion Enhancement Techiniques in Neuromusculoskeletal Disorders – presentation at the 7th International Conference on Noninvasive Ventilation – Across the Spectrum from Critical Care to Home Care – March 14-17, 1999, Orlando, Florida, USA