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Coma Recovery Association, Inc.
Swallowing is one of the most complex functions of the body. The anatomy required is a mouth that closes completely, a tongue that can be moved about inside the mouth, a windpipe (trachea) that can close off during passage of food from the mouth (oral cavity) into the food pipe (esophagus), a food pipe that can contract segmentally (peristalsis), to pass the food down to the stomach, and a stomach opening that will open and close appropriately. Multiple sensory and motor systems must function to assure a smooth swallowing process - liquid or food has to be perceived in the mouth, the location and consistency has to be determined, the tongue then has to be ordered to direct the contents into the back of the mouth (pharynx). At this point, simultaneously, breath must be held, the wind pipe--which is in front of the food pipe--has to close off to prevent aspiration, and the muscles of the back of the mouth (pharynx) have to contract to propel the food into the esophagus. As soon as the food is in the esophagus, the windpipe has to open up again and breathing has to resume. This delicate interplay between the respiratory systems and the digestive system requires perfect timing and synchrony of events to prevent choking, regurgitation, aspiration, asphyxia, vomiting--. The central nervous system controls for both mechanisms are in the brain stem and are modulated by higher centers scattered throughout the midbrain and the cortex of the brain. The smooth operation of the process requires at least a relatively healthy brainstem. The swallowing mechanism can return before a patient emerges from coma. In other instances, a patient may be fully alert, but may recover the ability to swallow properly. Early attempts to have a patient swallow nutrition by mouth must be carried out with extreme caution, and under professional supervision or guidance. If an individual cannot swallow their own saliva and/ or does not have a strong cough, feeding by mouth should not be attempted. These functions have to be checked periodically in an unresponsive patient since they may return before the patient displays any ability to communicate in any way, and if they do return, oral feedings are preferable to pre-mixed tube feedings. Mihai Dimancescu, MD Copyright © 1989-2000, * Coma Recovery Association, Inc.
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