Digestive Diseases and Sciences, Vol. 39, No. 4 (April 1994), pp. 762-765

Effect of Body Position on Deglutition E. D E J A E G E R , MD, W. P E L E M A N S , MD, PhD, E. P O N E T I ' E , MD, PhD, and G. V A N T R A P P E N , MD, PhD

This study examined the effects o f changes in body position on different swallowing parameters derived from manofluorographic examinations. Quantitative data were obtained in a group o f 12 young healthy volunteers. They were all tested in the upright position; six of them were also evaluated in the supine position, and the other six in the upside down position. In the different positions all volunteers were able to swallow a liquid bolus without aspiration or stasis. However, the dynamics o f the swallow became different. Lying down resulted in a pharyngeal transit time comparable with the upright position. The tongue driving force was higher and the hypopharyngeal suction power weakened. In the upside down position, the pharyngeal transit time became longer and the tongue driving force was even more powerful. There was no apparent difference in the traditional manometric parameters; the amplitude, duration, and propagation velocity of the pharyngeal contraction on swallowing did not change obviously in the different body positions. KEY WORDS: manofluorography; swallowing; body position.

Swallowing is a v e r y complicated act and the dynamics of swallowing are still not completely understood. A previous manometric study indicated that upright swallows differed from supine swallows primarily in the relationship of the nadir of the upper esophageal sphincter (UES) relaxation to the peak and the end of the pharyngeal contraction (1). In the concept proposed b y McConnel (2), the tongue driving force (TDF) and the hypopharyngeal suction pump (HSP) are the most important driving forces responsible for bolus transport. This study was undertaken to get additional information on the driving forces operating during oropharyngeal transport. Different b o d y positions were chosen to change the deglutition act. Swallows were quantified using manofluorography. Manuscript received September 24, 1992; revised manuscript received June 2, 1993; accepted June 29, 1993. From the Department of Internal Medicine, Division of Geriatric Medicine and Gastroenterology, Department of Radiology, University Hospitals, K.U. Leuven, Belgium. Address for reprint requests: Dr. E. Dejaeger, Division of Geriatric Medicine, University Hospital St. Pieter, Brusselsestraat 69, B-3000 Leuven, Belgium.

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MATERIALS AND M E T H O D S This study analyzed the swallowing act in 12 young healthy volunteers (age 31 years _ 8 years, nine males, three females). They all received a bolus of 10 ml liquid barium and performed a single swallow in the upright position. The first group (four males, two females, age 33 years _ 9) was asked to swallow an identical bolus in the supine position. The other six (five males, one female, age 29 years _ 6) swallowed 10 ml barium in a completely upside down position (180°). Manofluorography was used to measure various deglutition parameters. A manometric probe with five microtransducers, all 1 cm in length with a pressure-sensing portion of 1 mm and all oriented in the same radial direction, was passed transnasally. The first sensor was located at the tongue base; the second, fourth, and fifth were all positioned at 4-cm intervals, which corresponds approximately to the entrance of the larynx, the upper esophageal sphincter (UES), and the cervical esophagus, respectively. The third microtransducer, situated 1.5 cm proximal to the fourth, provided additional information on the high-pressure zone. All microtransducers were positioned with the sensor oriented posteriorly. The output of the different transducers and the fluoroscopic images were directly displayed on a TV screen and recorded Digestive Diseases and Sciences, Vol. 39, No. 4 (April 1994)

016342116/94/0400.0762507.00/0 © 1994 Pie hum Publishing Corporalion

BODY POSITION AND SWALLOWING TABLE1. SWALLOWINGPARAMETERS1NDIFFERENTPOSITIONS(MEAN -- SD VALUESUNLESSSTATEDOTHERWISE) PTT (seconds) TDF (mm Hg sec) OPP (mm Hg see) HSP (mm Hg see) Amplitude of the pharyngeal contraction (mm Hg) Duration of the pharyngeal contraction (sec) Velocity of propagation of the pharyngeal contraction (cm/sec)

Upright

Supine

P value*

Upside down

P valuer

0.98 _+ 0.17 2.1 -+ 1.0 3.0 -- 2.3 -3.4 _+ 1.8

1.07 - 0.23 3.0 - 1.7 6.7 _+ 3.2 -1.1 (0- -2.7:~)

NS 0.036 0.036 0.036

1.13 -+ 0.15 7.4 - 2.8 11.8 - 3.5 -0.7 (0- -2.9:~)

0.036 0.036 0.036 0.036

113 -+ 20

107 -+ 18

NS

120 -+ 21

NS

0.50 +_ 0.08

0.52 -+ 0.08

NS

0.58 _+ 0.07

NS

7.7 +_ 2.5

7.1 _+ 1.3

NS

7.2 - 2.8

NS

*Comparing the results of the same six volunteers in an upright and in a supine position. tComparing the results of the same six volunteers in an upright and in an upside down position. :]:Range.

on videotape together with a time display for later slowmotion and frame-by-frame analysis. The manometry data were separately recorded on a polygraph (Siemens-Elema). This allowed an accurate quantitative analysis of the pressure waves. By analogy with McConnel (2-7), the following parameters were measured: the pharyngeal transit time (PTT), the tongue driving force (TDF), the oropharyngeal propulsion pump (OPP), and the hypopharyngeal suction pump (HSP). When required, pressure integrals were calculated by computer using specifically designed software. The pharyngeal transit time and the duration of the pharyngeal contraction were determined on the videotape. The transit time was measured from the moment the bolus head reached the first sensor in the oropharynx until the time the bolus tail left the fourth sensor in the UES. The duration of the pharyngeal contraction was measured at the second transducer. Amplitude and velocity of the pharyngeal contraction were calculated on the polygraphic tracings. The height of the pharyngeal contraction peak was measured at the second transducer. The velocity of the pharyngeal contraction wave was calculated as the time interval between the pharyngeal contraction on the tracing of the second transducer and the postrelaxation contraction peak of the fourth transducer. Knowing the time interval between the two pressure peaks and the distance between the two transducers (ie, 4 cm), the velocity of pharyngeal contraction could be calculated. However, this parameter could not always be determined with a high accuracy since the nadir of the pressure peaks may show a small plateau, which makes different interpretations possible; here the middle of the plateau was chosen. Informed consent was obtained from all the volunteers. The study was approved by the Ethical Committee of the University Hospitals, Leuven. The data within each subgroup (supine, upside down) were compared to its own control group using a Wilcoxon signed-ranks test, and the differences between these two subgroups (ie, supine versus upside down) by a Wilcoxon rank-sum test. A two-tailed P value of less than 0.05 was considered to indicate statistical significance. Digestive Diseases and Sciences, Vol. 39, No. 4 (April 1994)

RESULTS The results are s u m m a r i z e d in table 1, Upright versus Supine Position. We noted a significant increase in T D F and O P P and a significant decrease in H S P . O t h e r p a r a m e t e r s w e r e not significantly different. Upright versus Upside Down. T h e P T I ' , T D F , and OPP w e r e all significantly increased, while the H S P showed a significant decrease. The amplitude of the pharyngeal contractions remained unchanged. The duration s h o w e d a t e n d e n c y to increase and the velocity s e e m e d to decrease, but neither change w a s significant. Supine versus Upside Down Position. T h e r e w a s no significant difference between the P T T m e a s u r e d in the supine or upside down position. H o w e v e r , the T D F and the OPP w e r e higher in the upside d o w n position (TDF: P = 0.02; OPP: P = 0.05). T h e H S P w a s (nonsignificantly) lower in the upside down position than in the supine position.

Upright versus Supine versus Upside Down (table 1, and figure 1). The swallowing p a r a m e t e r s in the upright position w e r e not significantly different between the two groups of six volunteers. Figure one illustrates the m e a n s for T D F , OPP, and H S P (12 subjects in the upright position, six subjects in the supine and six others in the upside down position). The rise of the T D F occurred primarily b e t w e e n the supine and the upside d o w n position; the decrease of the H S P , h o w e v e r , w a s already v e r y pronounced w h e n changing f r o m upright to a supine position. T h e changes in O P P p r o v e d to be fairly constant. Identical results w e r e obtained w h e n w e looked at the individual values of our volunteers. Qualitative Evaluation. All swallows in all posi-

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DEJAEGER ET AL

TDF-OPP-HSP DIFFERENT POSITIONS mm HI;

see

15

o - -

-5

tdf I

upright(12p)

opp ~

supine(6p)

hsp ~

upside down(6p)

Fig 1. Means for the TDF, OPP, and HSP in different body positions.

tions proved to be normal, without stasis or even the slightest aspiration. DISCUSSION The changes in body position performed by our volunteers are certainly not advisable for safe and comfortable eating. However, this study aimed to find out which components are essential for the propulsion of a liquid bolus in these unusual body positions. A liquid bolus was used since the majority of the functional disturbances of swallowing are more pronounced when liquids are ingested. The traditional parameters were calculated, ie, amplitude, duration, and velocity of propr.gation of the pharyngeal contraction. We also performed an additional analysis based on the concepts of McConnel and calculated the PTT, TDF, OPP, and HSP. Neither the pharyngeal transit time nor the amplitude, duration, or velocity of the pharyngeal contraction wave were influenced by the change from the upright to the supine position. The TDF and the OPP were significantly increased, whereas the HSP was significantly decreased. According to McConnel, the TDF and HSP are more important for bolus propulsion than the pharyngeal contraction. These results suggest that the rise of the TDF compensates for the diminution of the HSP leading to a fairly stable PTT. In the upside

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down position, however, the PTI" was significantly longer, and both the TDF and OPP were significantly higher compared to the upright position, whereas the HSP was significantly lower. In four of the six subjects, the suction power was completely absent. There were no significant changes as far as the amplitude or the duration of the pharyngeal contraction or the velocity of the pharyngeal peristaltic wave were concerned. Our observations suggest that the increase in TDF is no longer sufficient to compensate for gravity and for the nearly complete absence of suction power. As a result, the transit time gets longer. In conclusion, these data are in agreement with the concept of McConnel, and stress the importance of the TDF, OPP, and HSP as driving forces for a liquid bolus. On the other hand, clear changes on the videoscreen and a change in the PT'r are not reflected in the traditional parameters of amplitude, duration, and propagation velocity of the pharyngeal contraction. CONCLUSION When a subject is lying down or is standing upside down, the tongue driving force is higher and the hypopharyngeal suction power is less than in the upright position. The TDF becomes the main driving force responsible for bolus transport in these posiDigestive Diseases and Sciences, VoL 39, No. 4 (April 1994)

BODY POSITION AND S W A L L O W I N G

tions. The suction power exerted by the opening of the UES decreases gradually and, in the upside down position, it disappears completely in the majority of persons involved in our study. The tongue driving force seems adequate to maintain the PTT fairly constant up to the supine position. The changes in the duration or in the propagation velocity showed a pattern but were not significant. However, further investigation is required for the evaluation of the importance of these parameters. We realize that the numbers are small and further confirmation of these data would be most welcome. REFERENCES 1. Castell JA, Dalton C, Castell DO: Effects of body position and bolus consistency on the manometric parameters and

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coordination of the upper esophageal sphincter and pharynx. Dysphagia 5:179-186, 1990 McConnel F: Analysis of pressure generation and bolus transit during pharyngeal swallowing. Laryngoscope 98:71-78, t988 Mendelsohn M, McConneI F: Function in the pharyngoesophageal segment. Laryngoscope 97:483-489, 1987 Cerenko D, McConnel F, Jackson R: Quantitative assessment of pharyngeal bolus driving forces. Otolaryngol Head Neck Surg 100:57-63, 1989 McConnel F, Guffin T, Cerenko D, Shyh-Feng A: The effects of bolus flow on vertical pharyngeal pressure measurement in the pharyngoesophageal segment: Clinical significance. Otolaryngol Head Neck Surg 106:169-174, 1992 McConnel F, Cerenko D, Hersh T, Weil L: Evaluation of pharyngeal dysphagia with manofluorography. Dysphagia 2:187-195, 1988 Nilsson M, Isberg A, Shiratzki H: The location of the upper oesophageal sphincter and its behaviour during bolus propagation--a simultaneous cineradiographic and manometric investigation. Clin Otolaryngol 14:61-65, 1989

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