Portuguese Version

Year:  2000  Vol. 66   Ed. 5 - (2º)

Artigos Originais

Pages: 434 to 437

Study of Faringeal Fase of Deglutition in Healthy Volunteers by Fibronasoscopy.

Author(s): Ari de Paula*,
Jairo D. Fernandes**,
Marcelo B. Fortinguerra**.

Keywords: fibronasoscopy, deglutition, pharingeal fase

Abstract:
Method: This study was made of the pharingeal fase of deglutition in healthy volunteers by fibronasoscopy with the intention of seen the normality pattern of this exam. Liquid iogurt was used like contrast. Results: The results were agreed with the literatura. Conclusion: The exam was showed to be of easy execution, fast and great for seen the action and anatomy of the muscles involved in this fase of deglutition, as well as to show the aspiration or penetration of the contrast into the larynx.

INTRODUCTION

Swallowing is one of the most complex neuromuscular processes of human body. It has a voluntary component and an involuntary one, it mobilizes more than a hundred of muscles and lasts for only a few seconds.

It has 4 distinct phases: oral preparatory, oral, pharyngeal and esophageal phases (Mckee et al.).

We know that swallowing reflex takes place when areas of the brainstem - specifically pons and medulla, are stimulated. On the pons, dorsal and ventral regions of trigeminal nucleus, when stimulated, produce swallowing, but these regions are more related to sequencing of swallowing process than to its control. The nucleus of solitary tract, located on the dorsal medulla, and the ambiguous nucleus, located on the ventral portion of medulla, are the areas responsible for the control of swallowing and the esophageal phase of swallowing.

Cerebral cortex is the main area responsible for voluntary oral and pharyngeal phases of swallowing. Other cerebral regions related with swallowing are: paracentral cortex, sylvian cortex, pre-central gyrus, and posterior portion of inferior frontal gyrus, associated with duration and intensity of swallowing.

Afferent pathways have the main function of stimulating and modifying swallowing. They are represented by superior laryngeal, glossopharyngeal, trigeminal and lingual nerves. Trigeminal nerve is relatively inefficient to produce swallowing. The function of lingual nerve is to inhibit swallowing.

Sensorial cells are distributed throughout the oral and pharyngeal cavities, and studies have demonstrated that tonsil pillars are the most sensitive region to light pressure stimuli, whereas posterior pharyngeal region is the most sensitive to stronger pressure stimuli, to trigger swallowing.

Swallowing process is modified according to age, and the most frequent alteration is the change in direction of food bolus in the subglottic segment during swallowing (Plant). There is also reduction of muscle strength, requiring the need for a larger number of swallowing movements in order to clean oral cavity. There is also increase in swallowing duration (Plant, Mckee et al.). Elderly patients have 3 times more risk of aspiration than younger subjects. In esophageal phase, there is a smaller number of peristaltic contractions and reduction of pressure on upper esophageal sphincter (Mckee et al.).

In children, the process of swallowing is totally developed at 9 months of age (Darrow et al.). Children with history of maternal infection, drug abuse, polyhydramnios, anoxia during delivery, low Apgar, and prolonged resuscitation have high risk of developing swallowing pathologies.

There are no significant differences concerning swallowing and gender (McKee et al.).

Swallowing is influenced by the characteristics of the food to be swallowed, either liquids or pastes (Dantas et al.). Duration of swallowing is longer for paste food than for liquid ones (Dantas et al.; Ertekin et al.). Volume did not modify duration of swallowing (Dantas et al.).

Semi-solid foods require less muscular effort from the larynx and pharynx to be swallowed than liquid foods (Dantas et al.).

Swallowing may be studied in different ways, such as based on history and physical exam, ideal to study the alterations of oral phase; ultrasound, used to investigate oral phase and tongue movements during this phase in infants, because the teeth hinder the capture of images in the ultrasound; cineradiography and fluoroscopy are radiographic studies used to investigate oral, pharyngeal and esophageal phases of swallowing, using a radiopaque contrast; more recently, though, we have used fiberoptic endoscope to study pharyngeal phase of swallowing.

The objective of the present study was to investigate pharyngeal phase of swallowing in people without complaints of dysphagia or other swallowing alterations, using flexible fiberoptic naso endoscope, aiming at obtaining normal parameters for the exam.

MATERIAL AND METHOD

We conducted fiberoptic flexible nasoendoscopy in 10 volunteers (6 male and 4 female subjects) aged between 23 and 32 years without complaints of dysphagia.

All patients answered a questionnaire consisting of 15 questions about swallowing and we only included in the study those who answered negatively to all questions. The questions were:

o Have you noticed any modification in the duration of your meals lately?

o Have there been modifications in your diet or in foods that are more or less tolerated?

o Do you have difficulty to start to swallow?

o Do you have to swallow 2 or 3 times?

o Is there food left on the tongue and in the vestibule after you swallow?

o Is there nasal reflux?

o Do you feel as if the food had got stuck?

o Have you lost weight recently?

o Are you avoiding any kind of food?

o Do you have to clear your throat after eating or drinking?

o Do you feel breathless or cough while eating or drinking?

o Do you get hoarse during or after eating?

o Do you frequently have respiratory infections?

o Do you take any medication? Which one?

o Do you have any diseases?

Patients were submitted to physical exam of oral cavity.

We conducted fiberoptic nasoendoscopy while patients were seated, facing the monitor in order to give them some feedback and enhance cooperation during exam. We did not use local anesthesia on the nose or pharynx.

Endoscope was positioned initially in the cavum to visualize the function of soft palate during swallowing. Later, the endoscope was placed at the level of uvula, to have a view of tongue basis, posterior and laryngeal pharyngeal walls and endolarynx. At the end of the exam, the endoscope was placed at the level of superior pole of epiglottis, to have a better view of piriform sinuses, endolarynx and closing pattern of airways during swallowing.

All exams were recorded in video, so that they could be seen and re-evaluated later.

The food presented to the patient was regular liquid white yogurt, in a plastic cup and sucked with a straw. The amount was not measured and we only suggested that the patient sucked with the straw a large quantity, if possible.

First, we asked patients to swallow without yogurt to observe muscle activity and clearing of saliva in the pharyngeal region. Next, we asked the patients to take the yogurt and maintain it in the mouth. After, they swallowed it naturally. Next, we asked them to suck as much as possible and to swallow it at once, and finally, taking the large quantity again, to swallow it in three consecutive movements.

We studied, consequently, accumulation of yogurt in some phases as well as clearance of residues.

RESULTS

All patients considered normal subjects did not have complaints of dysphagia and answered positively all questions submitted in the questionnaire, aimed at detecting any disorder of the mechanism of swallowing.

Oral cavity exam was considered normal in all patients.

We studied anatomy of pharyngolaryngeal region, presence of accumulated secretion in hypopharynx, number of swallowing movements required to clean the pharynx, sensation of clean pharynx, and efficacy of cough in freeing larynx from food particles that could be penetrated or aspirated. We defined them as follows:

o Penetration: the passage of food into larynx without overtaking true vocal folds; and

o Aspiration: passage of food into larynx overtaking true vocal folds.

All studied subjects had normal pharyngolaryngeal anatomy, absence of accumulated secretion on vallecula, posterior and lateral walls of pharynx and piriform sinuses. They all reported a feeling of cleanliness in the pharynx after swallowing of yogurt.

All patients had normal vocal folds.

All subjects managed to retain the yogurt in the mouth without presenting escape of food into the pharynx before starting swallowing.

When yogurt was swallowed, all the following regions were stained in all subjects: vallecula, lateral and posterior pharyngeal walls, and piriform sinuses.

They all had good velopharyngeal function during swallowing, with complete closure of cavum and no occurrence of food reflux into nasopharynx.

When asked to swallow 3 times, the food took the following path: vallecula-lateral wall - piriform sinuses (Chihhsies et al.; Dua et al.; Aviv et al.). If a large quantity was swallowed, a part took the lateral path and the other went over the epiglottis (Dua et al.).
Only one patient had penetration of food into the larynx and it was satisfactorily cleaned with a cough movement.

Three subjects required only one swallowing and seven required two swallowing movements to clean the pharynx. They all reported a feeling of pharyngeal cleanliness after swallowing. We considered a clean pharynx when there was absence of food residues on vallecula, lateral and posterior pharyngeal walls and piriform sinuses.

We found 4 patients with signs of gastroesophageal reflux - 3 men and 1 woman. We considered signs of gastroesophageal reflux the presence of erythema, edema and granulation of arytenoids and interarytenoid region.

DISCUSSION

Swallowing is an extremely important process for the body because it is through it that water and nutrients are delivered to gastrointestinal tract and are absorbed; alterations in this mechanism may take the subject to a certain degree of malnutrition, impacting negatively the organism.

Pharyngeal phase of swallowing is important for the dynamics of swallowing, because it takes place between the respiratory and digestive systems, and problems in this phase seem to aggravate the risk of aspiration and increase morbidity and mortality of patients.

Fiberoptic endoscope is an excellent method to study pharyngeal phase of swallowing, because it enables direct visualization of the region during the act of swallowing. It is an easy, quick and non-painful method that may be conducted on the bedside of patients and there is no radiation exposure. Some inconveniences are high cost of device, and the need of a trained professional.

The results of this study are in accordance with those found by Wu et al., Costa et al., Aviv et al. and Dua et al..

We found a significant number of patients with signs of gastroesophageal reflux in the present study, which was not mentioned by any other author. However, this finding did not interfere in swallowing movements.

CONCLUSION

We may conclude that the study of pharyngeal phase of swallowing using fiberoptic nasoendoscope is a feasible and relatively easy method to use. It is not too uncomfortable for the patient and it presents an excellent view of anatomy and function of local muscle groups, as well as better visualization of presence of aspiration or penetration.

This kind of assessment conducted with liquid food in normal 23 to 32 year-old adult subjects of both sexes presented the following pattern:

o Retention of food in the mouth without escape into pharynx before swallowing;

o Passage of liquid food when swallowed in small quantity goes through the vallecula, lateral and posterior pharyngeal walls and piriform sinuses. If a large quantity is swallowed at once, a part goes over the epiglottis and another follows the previous path;

o Up to two movements of swallowing were required to free pharynx from food;

o Absence of aspiration or penetration of food into larynx after swallowing.

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* Professor and Preceptor of Medical Residence at Santa Casa and Hospital Irmãos Penteados, in Campinas.
** Resident of the Service of Otorhinolaryngology at Santa Casa and Hospital Irmãos Penteado, in Campinas.

Address for correspondence: Santa Casa a Hospital Irmãos Penteado, de Campinas - Departamento de otorrinolaringologia - Av. Julio de Mesquita - Cambuí -13025-061 Campinas/ SP - Tel.: (55 19) 232-4478.
Article submitted on March 17, 2000. Article accepted on June 1, 2000.

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