Mealtime Partners, Inc.

In many of the articles in the Mealtime Partners Newsletters, caregivers who feed other people are encouraged to provide small bites of food and sips of liquid, rather than large bites and gulps of liquid. This article will try to shed some light on the “technical” reasons for these recommendations.

The processes of eating and drinking are two of the most basic human functions and almost everybody eats and drinks by mouth. The process of eating and swallowing, or deglutination, involves the interaction and coordination of many muscles and nerves to permit food to be transported from the mouth to the stomach, safely. Yet the vast majority of us eats and drinks without difficulty, almost automatically. We might choke on a very rare occasion, especially when we hurry or are distracted, but as a whole, meals, drinks, and snacks are given little attention beyond what is being consumed. And, when we do choke, we cough vigorously and dislodge whatever went down “the wrong way”, and are back to normal in just a few minutes.

Choking and aspiration occurs when the interplay between the respiratory system and the digestive system does not coordinate properly. The definition of choking is an object is in the airway. Partial or complete obstruction of the airway can be due to a foreign body (e.g., food, a bead, toy, etc.) entering it. When an object blocks the airway there is a sudden onset of respiratory distress with coughing. If the object is not removed the person will be unable to breathe. Uncorrected choking can be very serious and result in death (www.medterms.com). Aspiration¹ is when solids or liquids that should be swallowed into the stomach are instead breathed into the respiratory system and penetrates below the true vocal cords, or when substances from the outside environment are accidentally breathed into the lungs¹. Aspiration can result in aspiration pneumonia (an infection in the lungs) and is also very serious.

Obviously, all of us breathe ongoingly. Breathing continues while we chew a mouthful of food, just as we do when we are not eating or drinking. However, when we swallow, whether it is a “dry swallow” (only saliva), or a swallow to process food or liquid, our breathing must stop while we swallow. This is known as an apneic event². The period that breathing stops (the apneic period) varies in length considerably depending upon both the individual and the texture of the food or liquid being swallowed. We all follow a respiratory pattern even though the pattern differs from person to person. The majority of people chew and form a bolus; when the bolus is moved to the back of the mouth, they exhale (breathe out), stop breathing (apneic event), swallow, and then inhale. Some people inhale prior to the apneic event and exhale once it is over. The volume of the bolus being swallowed will impact the organization of this respiratory pattern.

Eating starts before food reaches the mouth when saliva is produced in anticipation of eating. The body position that the person is in while they eat greatly impacts their function when food is received. Previous Newsletters (July 2009 and March 2010) have addressed issues relating to position while eating. Once food enters the mouth, its texture affects how it is handled. For example, a cracker will need to be broken into very small particles by the teeth and the particles will be mixed with a significant amount of saliva as they are moved around the mouth by movement of the tongue and jaw to form a ball, or bolus, before it is swallowed. Yet a bite of soft food, like pudding, needs little or no chewing but only needs to be formed into an appropriate sized bolus and swallowed.

Lazareck and Moussavi³ describe normal swallowing as: “involving intricate control and coordination of three swallowing phases, commonly referred to as oral, pharyngeal, and esophageal”. The oral phase is when food is in the mouth and being chewed and mixed with saliva; the pharyngeal phase is when a bolus is formed in the mouth and is passed to the back of the mouth to the epiglottis (the flap of cartilage that is attached to the root of the tongue and keeps food/liquid from going down the windpipe⁴); and the esophageal phase which is when the bolus enters the esophagus (the tube that connects the throat with the stomach).

Many studies have been conducted over the past several decades to gain a greater understanding of the swallow function and its interaction with respiratory function. Also, studies have evaluated changes in swallow function that occur when both different volumes of food or liquid are consumed, and when they are swallowed at a different pace^5&6. However, for those who feed individuals who are unable to self-feed, there is little in the literature to guide them as to when to provide each bite of food or a drink. It is difficult for even a very observant feeding partner to see each time the person being fed, swallows. Even more difficult, is to know whether they will require additional swallows to clear their mouth after a single bite of food. Compounding this problem is the fact that meals are time consuming and most people who feed someone else have other people to feed, or other chores to attend to. This time constraint encourages feeding someone quickly. If the person has not cleared their mouth of food prior to receiving the next spoonful of food, they tend to hurry to clear their mouth, and in doing so they reduce the number of chews per bite of food. As a result, the size of the particles of food that make up the bolus are larger than those making up a bolus of well chewed bites. This process creates an environment that can promote choking or aspiration.

The same risk occurs when liquid is provided if the person is required to drink quickly. When drinking, if swallow after swallow occurs without a break for a breathe, the risk of choking or aspiration increases proportionally with the number of consecutive swallows, as the respiratory pattern becomes less organized with each swallow. To provide the safest environment, adequate time should be provided between each swallow to allow for the appropriate breathe/swallow pattern to occur, whether eating or drinking.

When swallowing difficulties are suspected, the best method of evaluating an individual’s swallowing is through videofluoroscopic examination (VFE). However, VFE must be limited because of the exposure to radiation necessary to conduct the examination. Therefore, only a relatively short record of swallowing is possible. When a VFE is conducted, the patient eats or drinks (or both) food or liquid that has been mixed with barium and the movement of the barium-laced product is graphically recorded as it moves from the mouth into the throat and is swallowed. This allows clinicians to visualize the biomechanical movements of the swallow but does not necessarily expose the underlying causes for abnormal movement patterns. It should be noted that some people have “silent aspiration”. They aspirate without any outward signs such as coughing. If someone is suspected of any type of aspiration, medical advice should be sought as quickly as possible. Currently, VFE is the gold standard for identifying swallowing difficulties.

In conclusion, being able to control the quantity and pace of drinking or eating greatly reduces the risk of choking or aspiration. Adaptive equipment is now available for almost everyone to eat and drink independently, regardless of their disability. For eating, a full range of equipment is available ranging from simple adapted eating utensils to fully powered dining devices (like the Mealtime Partner Dining System). For independent drinking, a variety of drinking products are available from Mealtime Partners, Inc., that suit the needs of most individuals.