Instrumental Swallowing Examinations: Videofluoroscopy and Endoscopy



Instrumental Swallowing Examinations


Videofluoroscopy and Endoscopy


MICHAEL A. CRARY




CONSIDERATIONS FOR AN INSTRUMENTAL SWALLOWING EXAMINATION


Many instrumental procedures may be used to evaluate different aspects of swallowing function. This chapter addresses the two most commonly used procedures: videofluoroscopy (also called videofluorography) and flexible endoscopy (also known as fiberoptic endoscopy or transnasal endoscopy). Procedures related to these primary methods are introduced and other instrumental techniques for swallowing evaluation are briefly mentioned. However, before these instrumental evaluation procedures are detailed, they should be placed in the context of the overall clinical evaluation of the adult patient with dysphagia. Frequent questions about these procedures include “What are they intended to achieve?” and “When is an instrumental procedure indicated?” The following information is derived largely from practice guidelines published by the American Speech-Language-Hearing Association.13 The concept underlying the use of practice guidelines is that they result from the creative, clinical, and scientific input of many experienced professionals with thorough professional review. In that regard, although these views may change with the acquisition of new information at a given point in time, they represent a fair summary of existing knowledge and opinion.



Goals of Instrumental Swallowing Evaluations


Instrumental examinations of swallowing are only a part of the comprehensive examination of swallowing performance and function. In general, a thorough clinical examination (see Chapter 9) should precede any instrumental examination. The clinical examination can be important in tailoring specific questions to be addressed in an instrumental examination and provides a comprehensive clinical profile of patients in whom dysphagia is suspected. Thus instrumental examinations of swallowing may accomplish any number of objectives depending on the patient and the clinical situation. These examinations (1) provide valuable information on the anatomy and physiology of structures and muscles used in swallowing, (2) evaluate the ability of a patient to swallow various materials, (3) assess secretions and the patient’s reaction to them, (4) document the adequacy of airway protection and the coordination between respiration and swallowing, and (5) help evaluate the impact of compensatory therapy maneuvers on swallowing function and airway protection. Although the fluoroscopic and endoscopic examinations of swallowing function are not mirror images, they do share many common functions. In addition, each imaging study has specific attributes that the other may not possess. Furthermore, because each examination provides a permanent video record of the swallowing evaluation, both contribute to increased objectivity with enhanced documentation and the ability to review results of the respective studies.



Purposes of Instrumental Swallowing Examinations


Box 10-1 summarizes various purposes attributed to instrumental swallowing examinations. Perhaps the most overt purpose of any instrumental swallowing examination is the ability to image the structures of the swallowing mechanism and the movement of those structures during swallowing and other movements that may help assess their functional integrity. This assessment involves the lips, tongue, jaw, velopharyngeal mechanism, pharynx, larynx, and esophagus. Evaluation of these structures should incorporate some indication of anatomic adequacy and movement capability. In some cases it is possible to assess or perhaps infer sensory integrity and motor functions. Beyond basic anatomy and movement of specific structures, coordinated movement among various components of the swallow mechanism should be assessed with reference to swallowing function. This assessment requires the patient to swallow materials of varying sizes and textures to allow inspection of adjustments (either positive or negative) within the swallowing mechanism. This component of the instrumental examination can help identify misdirection (specifically entrance into the airway) of a bolus and post-swallow residue as a result of inefficient swallowing. If aspiration is identified, the instrumental examination is helpful in differentiating situations when the patient is more likely to aspirate versus those when aspiration is less likely. By using a variety of swallowed materials and incorporating compensatory maneuvers, clinicians may make inferences regarding the safest and most efficient material to swallow and the need for any postural or other adjustments that improve swallowing safety and/or efficiency. Secretions pooled within the swallowing mechanism can be problematic for patients and contribute to respiratory complications. These fluids should be identified and described, including the patient’s reaction to them and the patient’s ability to remove them from the swallowing tract. In some situations the clinician may conclude that oral feeding is not safe or adequate and hence might use the results of instrumental examinations to recommend nonoral feeding sources (or to recommend discontinuation of nonoral feeding sources with reestablishment of oral feeding). In short, instrumental examinations of swallowing function provide objective imaging of the swallowing mechanism that assists dysphagia clinicians in determining the need for and the direction of swallowing rehabilitation. More details of the fluoroscopic and endoscopic swallowing examinations are provided in later sections.




Indications for Instrumental Swallowing Examinations


Box 10-2 addresses three important questions: (1) When is an instrumental swallowing examination indicated? (2) When may an instrumental swallowing be indicated? and (3) When is an instrumental swallowing examination not indicated?1



Perhaps the basic answer to when an instrumental examination is indicated is “when the clinical examination fails to answer the relevant questions.” If the patient reports specific problems that are not clarified by the clinical examination, an instrumental examination is indicated. This examination may help clarify whether a significant dysphagia exists and delineate the parameters of that type of dysphagia—oral, pharyngeal, esophageal, or a combination of these components. Information from an instrumental examination may clarify airway protection issues that are potentially related to respiratory compromise or may elucidate swallow efficiency issues potentially related to nutritional decline. As previously mentioned, the impact of compensatory maneuvers may be verified during instrumental examination, and other information on swallowing movements may be garnered that facilitates direction in swallowing rehabilitation. Finally, in some instances information gained from an imaging study may contribute to a better understanding of the medical diagnosis contributing to dysphagia symptoms.


An instrumental swallowing examination may be indicated for various reasons, most of which are related to the condition of the patient. For example, some medical conditions pose a high risk for swallowing difficulty or may be complicated by swallowing difficulties that may not prompt a significant complaint from the patient. An instrumental examination provides an objective evaluation of swallowing ability that may facilitate early identification of problems and hence lead to improved care. In addition, clinical conditions may change over time because of changes in the underlying disease (i.e., progressive or recovering conditions) or changes in the patient (new treatments or new disease). Some patients present with clinical conditions that preclude adequate cooperation with a clinical examination (cognitive or communicative impairments). In this situation, an instrumental examination may help address the questions posed regarding swallowing ability.


Finally, in some clinical situations an instrumental examination is not indicated. Perhaps the most obvious is when the patient reports that he or she had difficulty in the past but no longer has any swallowing difficulty. Other situations might include the patient whose medical condition is too compromised to tolerate a procedure or who is too uncooperative to participate in a procedure. If the clinician judges that the patient’s condition will result in an instrumental examination that provides no useful information, a valid decision may be to delay the examination until the patient’s condition facilitates completion of a useful examination. The value of clinical judgment should not be underestimated. At times clinicians may simply feel that given all available information, the addition of an instrumental examination of swallowing function will not provide any further beneficial information.


Instrumental swallowing examinations—specifically fluoroscopic and endoscopic procedures that image swallow function—add an objective and valuable component to the comprehensive assessment of the patient with dysphagic symptoms. However, these examinations should not be isolated from the information obtained from a thorough clinical assessment. The combination of these tools is expected to provide the most complete clinical picture of the dysphagic patient, leading to the best possible treatment. Instrumental examinations of swallowing function address both the anatomy and physiology of structures within the swallowing tract and how movement of these structures may accommodate swallowing different materials. Clinicians also may assess the impact of immediate compensations with these examinations. Available guidelines offer suggestions for when an instrumental examination should, may, or should not be used; however, no guideline can account for all clinical situations. The judgment of the clinician with direct knowledge of the comprehensive picture is valuable in deciding when and how to use an instrumental examination of swallowing function.


The following sections address the videofluoroscopic and fiberoptic endoscopic swallowing examinations separately and subsequently compare the two procedures directly to help clinicians decide whether one, both, or neither of these procedures is appropriate in various clinical situations.



VIDEOFLUOROSCOPIC SWALLOWING EXAMINATIONS


What’s in a Name?


Various authors and health care institutions use different terms for what is essentially the same examination. Box 10-3 lists several name variants for this procedure. This list is not comprehensive but is probably representative of the variation that exists in nomenclature. The term modified barium swallow, initially coined by Logemann,4 can be interpreted literally. The traditional barium swallow is focused on the esophagus and stomach and uses large amounts of liquid barium (contrast agent) and still-frame pictures to image the expanded esophagus and evaluate gastric emptying or other upper gastrointestinal functions. This examination is usually done with the patient in one or more combinations of lying positions. The adult patient with dysphagia is likely to be compromised both by the large amounts of liquid barium and by the lying position during swallowing attempts. Therefore this examination was modified to use smaller amounts of contrast material varying in size and consistency and to examine the patient in an upright position (whenever physically possible) to resemble the position most typically associated with eating. This procedure has become known as the modified barium swallow (MBS).



Some health care professionals and researchers held to different conventions in selecting a name for this relatively new procedure. Gastrointestinal (GI) radiologists often referred to the procedure as an upper GI series with hypopharynx. This term reflects the traditional esophagram view but with the addition of a study of the hypopharynx. Other terms in the literature include videofluorographic swallow study (VFSS),5,6 videofluorographic barium examination (VFBE),7 and videofluorographic swallow examination (VFSE).8 Presumably, each of these terms was intended to identify the unique radiographic procedure that evaluates oropharyngeal swallowing function. Clinicians in different areas may know or use other terms that refer to the same study. This chapter uses the more generic name variant, videofluoroscopic swallowing examination.




Objectives of the Videofluoroscopic Swallowing Examination


The videofluoroscopic swallowing examination can have multiple objectives. The primary objective is to obtain a video image of the upper aerodigestive tract during the act of swallowing. By manipulating what is swallowed, how it is swallowed, and patient positioning, clinicians can complete a comprehensive assessment of swallowing ability. Box 10-4 lists the more overt objectives of a videofluoroscopic swallowing examination. Additional objectives may be appropriate for individual patients and/or problems.9



Evaluation of the swallowing mechanism is initially approached by identification and description of any deviations in the anatomy of structures within the swallowing tract. This presupposes the clinician’s detailed knowledge of anatomy, including radiographic anatomy. Figure 10-1 depicts both lateral and anterior radiographic views of a normal swallowing mechanism. Review of anatomic detail and examples of normal swallow physiology may be found in narrated Video 2-3 on the Evolve site that accompanies this textbook. Basic physiology of the swallowing mechanism may be evaluated by asking the patient to phonate, breath hold, perform a Valsalva maneuver, produce falsetto phonation, or perform other activities that facilitate movement of the structures within the swallowing tract. This component of the evaluation is helpful in identification of potential movement deficits that may contribute to oropharyngeal dysphagia and in selecting appropriate compensatory maneuvers.



Swallow physiology is evaluated by asking patients to swallow various amounts and textures of contrast materials. Knowledge of both normal and impaired swallow physiology is implicit in evaluating this component of the fluoroscopic examination. Abnormal aspects of physiology typically are detailed in terms of reduced or altered movement patterns. In addition, the consequences of physiologic impairments such as aspiration or residue are documented. Finally, the impact of therapeutic compensations is evaluated. Compensatory postures or swallow maneuvers are useful both for introducing immediate improvement in the safety or efficiency of the swallow and for identifying potentially beneficial therapy strategies.


Symptom confirmation is an important objective of any instrumental examination, including the videofluoroscopic swallowing examination. If a patient reports food sticking in the lower neck area, the fluoroscopic study should thoroughly evaluate that area. If nothing of consequence is identified there, other potential contributors to that symptom should be evaluated (in this specific case, the esophagus and lower esophageal sphincter should be thoroughly evaluated). Addressing this objective relies heavily on the clinician’s skill in focusing on the patient’s complaints and descriptions of dysphagia symptoms and in directing the fluoroscopic study to adequately evaluate those components of the swallowing mechanism that may contribute to a specific set of symptoms.


Given that the fluoroscopic swallowing examination is a time-limited event and cannot possibly sample all foods that a given patient might eat, a certain amount of prediction is involved in interpreting this examination. For this reason, we include “prediction” as an objective of the fluoroscopic swallowing examination. After a thorough evaluation of the structure and function of the swallowing mechanism, swallow physiology and consequences of impaired movement, and the impact of compensatory maneuvers, the clinician must engage in a series of educated decisions regarding the functional swallowing performance of each patient. Examples of such decisions include the potential for future health complications, such as aspiration-related pneumonias and/or nutritional deficits, the level of functional eating ability and any recommended diet level changes, the need for swallowing therapy and, if indicated, the specific direction of that therapy, whether additional clinical or instrumental evaluations are indicated, and if consultations with other health care providers are needed to address the problems identified in the current examination. These are only a few of the potential areas of prediction in which clinicians may engage. Ultimately, questions of safe and adequate oral intake of food and liquid must be directly addressed and based in part on the results of this examination.



Procedures for the Videofluoroscopic Swallowing Examination


A standard protocol is highly recommended for the fluoroscopic study.5,6,9 Standardizing the protocol increases consistency and reproducibility of examinations both within and across patients. The use of a standard protocol does not preclude individual variations that may be required for specific patients or problems; however, it does provide a consistent framework from which reasonable variations may be accomplished. Several factors within the protocol must be considered, including patient positioning, materials to be swallowed, sequence of attempted swallows, and what to look for, including interpretation and documentation of the findings.



Patient Positioning


Positioning depends in large part on the physical abilities of the patient. In general, this study is accomplished with the patient in an upright, seated position with adequate support for the head and body. Patients with physical limitations from weakness, fatigue, disease, or other reasons may require special positioning systems during the examination. Various commercial positioning chairs are available to assist in optimal positioning of patients with physical limitations. Before purchasing or building a positioning chair, it is important to know the physical dimensions of the specific fluoroscopic system to be used. Often there is a fixed maximum distance between the table and tower of the fluoroscope. In addition, this study is typically completed in lateral and anterior views. The selected chair or positioning system should be adaptable to accommodate both views. Finally, specifically for lateral views, large patients may not fit easily into the fixed space between the table and tower of the fluoroscope. In such cases, it is possible to turn the patient slightly toward an oblique orientation while maintaining a lateral perspective as much as possible.



Typically, the videofluoroscopic swallowing examination begins with the patient in a lateral (or semioblique) position in reference to the fluoroscopic image (Figure 10-2). This perspective affords an excellent view of the swallowing mechanism from the lips to cervical esophagus and provides the best view of the trachea separate from the esophagus. This view is beneficial in determining whether material enters the upper airway. After examination of the swallow in the lateral perspective, the patient is turned for an anterior view. This perspective permits excellent evaluation of symmetry along the swallowing mechanism. When the esophagus is imaged with the patient in a sitting position the extent of the view is often limited. In these situations, imaging is done with the patient in a standing or lying position depending on physical limitations of the patient or specific aspects of the dysphagia presentation. In fact, for some patients who can tolerate standing during the fluorographic examination without compromise, the entire examination can be done with the patient in a standing position. This situation permits a great degree of control in moving and positioning the patient.




Material Used in the Fluoroscopic Study


The key material used in the fluoroscopic swallow study is barium sulfate suspension. This is a positive contrast agent that is radiopaque. As a result, barium sulfate appears as black on the fluoroscopic image compared with negative contrast substances, such as air, which appear as varying shades of gray. Tissue and bone appear as shades of gray depending on their density. Figure 10-3 depicts the shades of the bolus in the mouth, various bony structures (including the hyoid bone), and the air spaces in the pharynx and the trachea.



A popular point of discussion and even argument among clinicians is whether to use barium sulfate in isolation or in combination with real food items. No firm answer has emerged from these discussions and proponents of both perspectives have seemingly valid points. Individuals who focus on isolated barium products for this study claim that the range of food textures is so great that it would be impossible to image every possible food or liquid that a given patient might ingest. Another argument against using real food is the potential for complications resulting from aspiration of food products into the airway. Proponents of combining barium and real food items argue that barium products do not represent the consistencies noted in real food products.


Regardless of the outcome of this food-versus-barium discussion, the importance of using a range of textures and volumes during the study cannot be overstated. It is well known that a normal swallowing mechanism adjusts to changes in bolus volume and/or texture.1013 In the absence of this accommodation, a patient with dysphagia may demonstrate a variety of compensations or demonstrate the consequences of impaired physiology and the inability to compensate. Volumes used in fluoroscopic swallowing studies vary across published reports. One consideration is the average amount ingested in normal-swallowing adults. Published literature suggests that approximately 20 mL of liquid represents the average drink from a cup.14 Moreover, an average teaspoon is approximately 5 mL. Therefore, based on a functional perspective, it seems reasonable that the majority of swallow attempts would include volumes somewhere within this range unless clinical indications exist to use less or more material. In fact, results of a recent study15 suggested that swallows of a 5-mL bolus of thin barium liquid and a 5-mL bolus of nectar-thick barium liquid contributed the greatest amount of information to interpretation of 15 physiologic swallowing components. The author’s standard protocol has been to use 5 and 10 mL of each material and then allow the patient to drink freely from a cup or by a straw whenever feasible or clinically indicated. This choice of volume and consistency is based in part on the functional considerations previously mentioned and in consideration of a study suggesting that when using standard materials, 5-mL and 10-mL volumes of thin and thick liquid demonstrated the strongest associations between clinical signs of aspiration and observed aspiration during the videofluoroscopic swallowing study.16


In addition to varying volume, consistency—or viscosity—is varied across swallows. General categories of viscosity or textures include thin liquid, thickened liquid, paste or pudding, and masticated material.7 One barium product line has attempted to standardize the viscosity of barium sulfate liquids into thin, nectar, and honey. A paste material also is available in this product line. One benefit of these standardized barium products is consistency and reproducibility of repeated examinations both within and across patients. In short, use of standardized materials reduces variability across examinations that might result from utilization of different materials.



Sequencing the Events in the Fluoroscopic Study


Different protocols have suggested different sequences of events during the fluoroscopic swallowing study. For example, Logemann9 recommends beginning with thin liquids in progressive sequential amounts (1 mL, 3 mL, 5 mL, 10 mL). Once thin liquid swallows are completed, pudding and then masticated materials are evaluated. Palmer et al.5 began their fluoroscopic swallowing protocol with 5 mL of thick liquids (this category includes pudding material in their protocol), followed by thin liquid and then masticated materials. Martin-Harris et al.15 initiated their protocol with 5 mL of thin liquid followed by thicker liquids, pudding, and a masticated material. However, this group did caution that larger, thicker, and masticated materials were given to patients only if they demonstrated adequate airway protection and pharyngeal clearance on the thin liquid materials. The author agrees that a standard protocol is beneficial when completing the fluoroscopic swallowing, but recommends flexibility in the sequence of events to maximize the “diagnostic outcomes” for each patient. Described below is a general sequence of events used in the author’s standard protocol for the videofluoroscopic swallowing study.


Initially the patient is seated and viewed from the lateral perspective. The first tasks often are simple speech or phonation activities to facilitate an impression of movement of structures in the swallowing mechanism (lips, tongue, velum, and pharyngeal wall). Subsequently the initial barium bolus is provided to the patient. Unless there is significant dryness (xerostomia), weakness, or anatomic deviation in the oral cavity structures, the initial bolus is typically 5 mL of thickened liquid. The next material would be 5 mL of thin liquid followed by 5 mL of pudding. This sequence is subsequently repeated with 10-mL volumes. The patient then is given a cup of thin liquid barium to drink freely and a masticated material coated with barium pudding (usually a cracker). Video 2-3 on the Evolve site shows examples of swallows of these and other materials by a healthy adult volunteer. Video 10-1 depicts examples of swallowing by patients with various dysphagia symptoms.


After this sequence of events is imaged from the lateral view, the patient is turned and viewed from the anterior perspective. From this view the patient is asked to sustain phonation or repeat the same vowel to visualize movement of the true vocal folds. Some patients are asked to phonate in a falsetto mode to evaluate medial movement of the lateral pharyngeal walls. Some are asked to perform a “trumpet” maneuver to evaluate potential weakness in the lateral pharyngeal walls. The trumpet maneuver is accomplished by asking the patient to lift the chin to provide a clear view of the entire pharynx. Then the patient is asked to puff the cheeks and blow as if playing a trumpet (Figure 10-4). Turning the head to each side during swallowing may assist in evaluating each hemipharynx and any effect on pharyngoesophageal segment (PES) opening. Materials used in the anterior view depend largely on the results of swallows examined with the lateral view. In general, not all materials are repeated with the change in orientation, but sufficient swallows are evaluated to assess symmetry, physiology, and the consequences of impaired movement.


Aug 27, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Instrumental Swallowing Examinations: Videofluoroscopy and Endoscopy
Premium Wordpress Themes by UFO Themes