Most of us never think about swallowing until we get a bit of food or a pill caught in our throat, or until a sip of liquid “goes down the wrong pipe.” However, swallowing is a highly complex balancing act. Approximately thirty mouth and throat muscles and multiple nerves must perform their actions precisely on cue. To understand this properly, let us look more closely at the aerodigestive tract, which comprises the mouth, throat, larynx (airway entrance), and upper esophagus.
The aerodigestive tract channels air for breathing. In breathing, the air must move from the nose or mouth into the larynx. It then goes into the lungs and back and out. If you choose to speak, the air moves the same way through the aerodigestive tract, but the vocal folds then must vibrate to produce sound.
In order for you to swallow, the aerodigestive tract becomes an effective food propelling mechanism. The tongue propels food into the throat, which sends the food on to the esophagus so that it can be digested. However, during its transfer from mouth to esophagus, the food temporarily sits right next to the larynx and trachea (windpipe), which lead directly to the lungs. The epiglottis is responsible for covering the airway entrance to protect it from the presence of the food, and the larnyx itself moves out of the path of the food. The vocal folds also close to protect the trachea and lungs from this foreign material.
This is a precarious situation, however. Occasionally, a piece of solid food can inadvertently go down the “wrong pipe,” that is, the windpipe. Unless very small in size, this food can then block the airway, causing an inability to breathe.
The same thing can happen with liquids or soft foods, too. Entry of food or liquid into the trachea is called aspiration, If this occurs repeatedly, it can result in pneumonia or other types of damage to the lungs. When food, liquid, or saliva finds its way down the wrong pipe, it eventually will reach the lungs unless it is coughed out of the airway and expelled through the mouth.
The manner in which we normally swallow does not permit us to inhale food into our trachea and lungs. In fact, swallowing is one of the few acts we humans perform during which we must stop breathing. When we swallow, the larynx, which sits on the top of the airway on the trachea, is closed, and simultaneously the sphincter at the top of the esophagus (which is closed when we are not eating or drinking so that we do not swallow air) is opened for food passage toward the stomach. These events, which must be timed precisely to the millisecond, are performed automatically by each of us approximately five hundred times per day.
Certain foods and liquids are easier or more difficult to swallow. Thin liquids, for instance, are most frequently aspirated because they can easily flow into a small opening, which is what occurs when the vocal folds at the top of the airway do not come together in a perfectly uniform manner. However, it is believed that thicker liquids are less likely to be aspirated. Although it is not clear why, the thought is that they offer increased viscosity. Viscosity is a property related to thickness and the manner in which a liquid flows. Viscosity is assumed to provide airway protection through increased sensory feedback, increased cohesiveness, and/or slowing of the liquid flow.
In terms of solid food, those foods that are dry and granular are most likely to cause aspiration. In fact, foods that do not maintain cohesion (that is, while in the throat, fall apart into little dry pieces, like rice or popcorn) may “particle-ize." thereby slipping easily through a narrow opening, or they may be inhaled easily.
In addition to the possibility of food or liquid being misdirected during swallowing, difficulty may occur because food stays in the mouth or in recesses in the throat that can “pocket” food. These recesses provide anatomic hiding places, so that after swallowing is completed, and breathing is resumed, the material is inhaled into the airway from those recesses where it has bean stuck or pocketed.
It has become clear that certain consistencies of food and liquid appear to be easier or safer to swallow. These include soft, easy-to-chew items such as cooked vegetables or canned fruit; moist foods; and thicker liquids.
Now that we understand a bit more about the intricacies of swallowing and aspiration, lets look more closely at the ways in which you can make swallowing easier.
Dysphagia, or difficulty swallowing, has been estimated to affect approximately 15 million Americans. Approximately three thousand adults die every year because food gets stuck in their throats and blocks their airways, making it impossible to breathe. This occurrence is so common that it has been nicknamed the “café coronary.” There is also the danger that food or liquid may enter the lungs, and result in recurrent infections or aspiration pneumonia. To reduce these risks, follow the guidelines and precautions listed below. These safe swallowing suggestions apply to everyone, with or without swallowing or chewing problems.
If swallowing or chewing is difficult, some additional specific principles should be observed. They are described in greater detail in the remainder of this article.
A word of caution: no two individuals are alike in their swallowing or chewing problems. A custom-tailored oral feeding program should be developed after a careful, detailed evaluation by an experienced team of health care professionals or a swallowing expert. Using the information from the swallowing evaluation, the experts can recommend strategies and plan a treatment determined to be the most appropriate.
Correct positioning of the head, neck, and body is critical to ensure safe swallowing, prevent choking or aspiration, and aid in digestion. The optimum posture for most individuals is to have the body seated in an upright position, with the head and neck tucked slightly forward, toward the chest. This posture protects the airway by positioning it under the tongue and prevents food from spilling into the airway.
Eating in bed should be avoided, but if it must be done, elevate the head of the bed in order to let gravity help the swallow. Or, position pillows to support the body and head in an upright position.
A person with a swallowing problem will require a posture or position specific to his or her swallowing needs. Postural techniques have been found to be effective in eliminating food entry into the airway in up to 80 percent of individuals with swallowing problems. Each posture must be carefully selected and evaluated by a swallowing therapist.
Prevention or control of gastroesophageal refiux (GER), which is the return of food upwards, is of special concern in individuals with swallowing problems. The esophagus is a long muscular tube that connects the mouth to the stomach. In the lower part of the esophagus, just above the stomach, there is a ringlike muscle that acts like a fist. The muscle is a one-way system that relaxes to allow food to pass on to the stomach, as well as to prevent stomach contents from moving upward into the esophagus, throat, or airway. Chronic reflux can cause problems such as chronic cough, hoarseness, difficulty swallowing, or damage to the vocal folds. Severe refiux can cause respiratory problems such as asthma, or, if stomach contents get into the airway, recurrent pneumonia. Common treatments include both lifestyle adjustments and medication. Over-the-counter medications may be helpful to treat the more common symptoms of refiux, such as heartburn. Other medications may need to be prescribed by a physician to neutralize or inhibit the production of stomach acid, or to improve emptying of the digestive tract. In severe cases of GER, surgery may even be necessary. However, most people with gastroesophageal refiux can be treated effectively with a combination of antacids and lifestyle modifications. These lifestyle modifications include changing posture, modifying diet, and changing eating habits. Common suggestions to control gastroesophageal reflux include the following:
Eating and drinking aids can assist in placing, directing, or controlling the bolus (a cohesive mass) of food or liquid, and maintaining proper head posture while eating. For example, use of modified cups with cut-out rims (placed over the bridge of the nose) or straws will prevent a backward head tilt when drinking to the bottom of the cup.
A backward head tilt, which results in neck extension, should be avoided in most cases. When the head is tilted backward, food and liquids are more likely to enter the airway. Spoons with narrow, shallow bowls or glossectomy feeding spoons (a spoon developed for moving food to the back of the tongue) are useful to individuals who require assistance in placing food in certain locations in the mouth. More important, these utensils and devices promote independence in eating and drinking. A swallowing expert can make suggestions regarding appropriate aids for swallowing problems.
Proper oral care is essential, as the bacterial makeup of saliva can be changed through reduced or weakened swallows, dental disease, or malnutrition. Such altered saliva aspirated into the lungs, either before or after it is mixed with food or liquid, can increase the likelihood of infection or aspiration pneumonia. So perform the following oral care procedures on a daily basis:
In contrast to the “fast food society” in which we live, individuals with swallowing and chewing problems take longer to eat because of weakened muscles. Because of the increased length of time necessary, many people do not eat enough. The resulting fatigue then compromises swallowing safety. However, the optimum time needed to eat safely still is not known, because every individual and situation differs. Likewise, the amount of food or liquid needed to initiate a prompt and safe swallow varies Typically, smaller amounts are less likely to enter or block the airway, but in individuals who experience a sensory loss to the mouth or throat after illness or injury, larger amounts of food or liquid may be necessary to trigger a swallow. To promote a safe and efficient swallow most individuals with swallowing and chewing difficulty should do the following:
Swallowing problems may affect an individual's ability to take medication safely and easily. In addition, the swallowing problem may interfere with medication absorption and effectiveness if the medication is consumed with inadequate amounts of food or liquid, or if taken incompletely. An individual who has difficulty swallowing thin liquids safely also will have difficulty swallowing thin liquid medications. On the other hand, pills or capsules may be particularly hard to swallow safely. Pill-induced damage to the esophagus can occur if pills are taken while lying down or with inadequate amounts of liquid. Certain pills can damage esophageal tissue if they are left in the esophogus to dissolve. Medicines also can enhance or interfere with the swallow. With certain disorders, such as Parkinson's disease, make sure that medication timing is monitored to allow the medicine to have its greatest effect at mealtimes. Many medications may cause dry mouth or esophageal dysmotility (inefficient esophageal function), which can interfere with the swallow. Consult with a doctor, pharmacist, or swallowing expert to help select medications that may be crushed, mixed with foods, or are available in liquid form.
For individuals with a swallowing or chewing problem, eating and drinking no longer are easy, natural, enjoyable, or safe. Often, a sequence of strategies or compensations must be used in order to swallow more easily and safely. If the swallowing or chewing problem was caused by illness or injury, other problems, such as impaired memory or difficulty concentrating, also may be present. Therefore, a quiet, distraction-free atmosphere while eating is important to promote safe swallowing and enhance appetite and intake. Helpful strategies to allow the individual to concentrate on swallowing and chewing and enjoy mealtime include:
Having a swallowing or chewing problem increases the risk of choking. Signs of choking include inability to cry out or speak, weak cough, grasping of the throat, labored breathing that produces a high-pitched noise, or loss of consciousness. The standard first aid technique to clear the airway is the Heimlich maneuver, or “hug of life." This maneuver involves standing behind the victim and wrapping the arms around the victim's waist. Next, a fist is pressed into the victim's stomach with a quick upward thrust and repeated until the object is expelled. Modifications are necessary if the victim is very obese, pregnant, a child, or an infant. Although the Heimlich maneuver can be self-administered, those with swallowing or chewing problems should always eat in the company of someone who knows this first air maneuver. It is strongly recommended that family members be trained in emergency techniques for clearing the airway. Also, consider using an emergency service that can be called by the push of a button. Further information on the Heimlich maneuver can be obtained from the American Heart Association at (80O-242-8721) or www.amhrt.org.
Certain warning signs may indicate the aspiration of food or liquid into the lungs. The changes listed below may occur, and if they do, they should be reported to the doctor and swallowing expert.
