Effect of Bolus Osmolality on Human Esophageal Function Claudio R.. Section of Gastroenterology, Department of Medicine, VSC School of Medicine, Los Angeles, California The effect of bol
Trang 1THE AMERICAN JOURNAL OF GASTROENTEROLOGY
Copyright© 1989 by Am Coll of Gastroenterology
Vol 84, No 6, 1989 Printed in U.S.A.
Effect of Bolus Osmolality on Human Esophageal Function
Claudio R Bilder, M.D., Cornelius P Dooley, M.D., M.R.C.P.I., and Jorge E Valenzuela, M.D., F.A.C.G.
Section of Gastroenterology, Department of Medicine, VSC School of Medicine, Los Angeles, California
The effect of bolus osmolality on human esophageal
function is undefined We sought to define the response
of the human esophagus to boluses with a wide range
of osmolalities in 10 healthy male volunteers
Intralu-minal pressure events were measured with an infused
catheter system, and lower esophageal sphincter
pres-sure was monitored continuously with a Dent sleeve.
Each subject was given a series of 10 swallows of each
of seven boluses, which consisted of water, mannitol
solutions with osmolalities of 142, 296, 449, 704, and
1481 mOsm/kg, and orange juice (585 mOsm/kg), in a
randomized fashion Tracings were coded and analyzed
blindly Alterations in bolus osmolality did not elicit
any significant changes in amplitude and duration of
contraction, velocity of wave propagation, or the
dura-tion of relaxadura-tion of the lower esophageal sphincter.
We conclude that bolus osmolality does not play a
significant role in the control of human esophageal
motility, and that this lack of effect is explained by
consideration of esophageal muscle mechanics.
INTRODUCTION The esophagus utilizes a complex and highly
coor-dinated pattern of neuromuscular activity to convey
ingested food and saliva to the stomach Certain bolus
attributes, such as volume (1, 2), viscosity (3), and
temperature (4, 5), are known to have a significant
modulating influence on esophageal peristalsis The
effect of bolus osmolality on human esophageal
func-tion has not been documented, although many
impor-tant functions in the upper gastrointestinal tract are
mediated through osmoreceptors (6, 7) The current
study sought to document the response of the human
esophagus to alterations in bolus osmolality
MATERIALS AND METHODS
Subjects
Ten normal male volunteers without any evidence of
gastrointestinal and esophageal disease were included
in this study Their ages ranged from 29 to 66 yr (mean
± SD 44 ± 11 yr), and all subjects gave fully informed
Received January 10 1989; revised February 14, 1989; accepted
February 16, 1989.
consent under a protocol approved by this institution's research committee
Esophageal manometry
Esophageal manometry was performed with a six-lumen manometric assembly that had four esophageal body recording sites radially oriented, a 6-cm sleeve (Dent) device for continuous recording of lower esoph-ageal sphincter pressure, and a gastric side-hole record-ing site at the distal end of the sleeve sensor The distal esophageal side hole was located at the proximal border
of the sleeve device, and the next esophageal sensor was located 3 cm proximally The two remaining esophageal body recording sites were each located at 6-cm intervals proximally The catheters were continuously perfused with gas-free water by a low-compliance pneumohy-draulic infusion pump (Amdorfer Medical Specialities Inc, Greendale, WI) at a rate of 0.5 ml/min Resistance
to infusion within the system was detected by a series
of external transducers (Statham P23DB, Statham Inc, Oxnard, CA) positioned at the intersection of the costal margin and mid-axillary line of the subject Sudden occlusion of each orifice resulted in a pressure rise in excess of 300 mm Hg/sec Pressure profiles were dis-played on a multichannel polygraph recorder (Beekman R611, Beekman Instruments Inc, Fullerton, CA) The recording assembly was passed orally and positioned with all recording orifices in the stomach Baseline pressures were set at intragastric pressure A station pull-through was performed to locate the lower esoph-ageal sphincter accurately The assembly then was taped
in position with the sleeve device straddling the sphinc-ter The resulting position located the distal esophageal sensor 3 cm above the midpoint of the sphincter (8) All studies were performed with the assembly in this position and the subjects supine
Study design
All subjects were studied after a minimum 6-h fast Once the manometric assembly was positioned cor-rectly, the subject was given a series of 10 swallows (each 5 ml) of water, a number of mannitol solutions, and orange juice The mannitol solutions were 5% (142 mOsm/kg), 10% (296 mOsm/kg), 15% (449 mOsm/ kg), 20% (704 mOsm/kg), and 25% (1481 mOsm/kg)
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Trang 2612 BILDER et al Vol 84, No 6, 1989
The corresponding osmolalities of water and orange
juice were 1 mOsm/kg and 585 mOsm/kg The order
of each set of swallows was randomized, and all boluses
were given at room temperature (23-26°C) All
swal-lows were separated by at least 30 s, and an event
marker was used to denote each swallow event If a
second swallow was incidentally initiated within 20 s
of the primary event, both swallows were excluded from
the subsequent analysis
Analysis of data
Individual tracings were coded and analyzed in a
blinded fashion for peristaltic wave amplitude and
du-ration, propagation velocity of peristaltic contractions,
and duration of lower esophageal sphincter relaxation,
as previously described (3, 8) For each subject,
peri-staltic parameters for each set of swallows were averaged
to give individual means Mean values for the group of
subjects thus represent the mean of the individual
means (1) Data analysis was performed with ANOVA
with p values of 0.05 being considered significant.
RESULTS
We were unable to demonstrate any significant
alter-ations in the parameters of esophageal peristaltic
func-tion during deglutifunc-tion of the boluses of varying
os-molality Specifically, wave velocity (Table 1),
ampli-tude of contraction (Table 2), and wave duration (Table
3) did not vary significantly with any of the boluses In
addition, the frequency of peristalsis did not differ
between the boluses, being >90% in all cases Further,
the duration of relaxation of the lower esophageal
sphincter did not change significantly with any of the
boluses utilized in the study (range, 7.3 ± 1.9 s t o 8.8
± 2.9 s) No alterations in the frequency of nonspecific
motor abnormalities was noted with any of the boluses
DISCUSSION The characteristics of the swallowed bolus have a
significant role in determining the physiological
re-TABLE 1
Effects of Alterations in Botus Osmotatity on Velocity of Propagation
(cm/sec) of the Peristattic Wave
TABLE 2
Effect of Alterations in Bolus Osmolatity on Amplitude of
Contraction (mm Hg)
Water
Mannitol 5%
Mannitol 10%
Mannitol 15%
Mannitol 20%
Mannitol 25%
Orange juice
Esophageal Segtnent"
18-12 cm 3.4 ± 1.1 3.2 ± 1.3 2.8 ± 0.7 3.8 ± 2 2.9 ± 0.7 3.2 ± 1.1 2.9 ± 1.2
12-6 cm 1.8 ±0.4 1.8 ±0.3
2 ±0.5 1.9 ± 0.4 1.9 ±0.4 2.1 ±0.4 1.9 ±0.4
6-3 cm 7± 1.3 8 ± 0.9 8 ± 0.9 8± 1 6 ± 0.9 7 ± 0.9 6 ± 0.6
Water Mannitol 5%
Mannitol 10%
Mannitol 15%
Mannitol 20%
Mannitol 25%
Orange juice Values are mean
\i
49 48 48 49 46 46 41
Esophageal Sensor Position*
i cm
± 3 1
± 3 2
± 3 2
± 2 7
±31
± 2 6
± 3 0
±SD.
* Refers to sensor position sphincter.
Effect of Alterations
Water Mannitol 5%
Mannitol 10%
Mannitol 15%
Mannitol 20%
Mannitol 25%
Orange juice
12 91 88 88 94 88 82 109 above
TABLE
ctn
± 4 5
± 51
± 4 2
± 5 3
± 5 0
± 5 5
± 6 2
6 cm
123 ± 119±
123 ± 113±
121 ± 113±
86 58 78 69 84 84
78 ±46
; midpoint of
3
3 cm
61 ± 3 1
62 ± 3 4
65 ± 4 4
63 ± 3 6
68 ±38
65 ±41
67 ± 4 2 lower esophageal
in Bolus Osmolatity on Duration of Contraction
IS 5.6 5.3 5.5 4.9 4.9 5.1 5.6
(s)
Esophageal Sensor Position*
cm
± 1.6
± 1.2
±0.9
± 1.3
±0.9
± 1.3
± 2
12 5.7 6 5.9 5.6 5.6 5.4 5.7
cm
± 1
± 1.1
± 1.4
± 1.3
± 1.3
± 1.4
± 1.3
6 cnr 6.1 ±
6 ± 6.2 ± 5.8 ±
6 ± 5.4 ±
6 ±
I
.3 1 4 2 3 2 4
3 cm 5.4 ± 0.4 5.8 ± 0.4 5.7 ± 0.9 5.2 ± 0.9 5.6 ± 0.9 5.7 ± 0.9 5.8 ± 0.8
Values are mean ± SD.
* Refers to segment position above midpoint of lower esophageal
sphincter.
Values are mean ± SD.
* Refers to sensor position above midpoint of lower esophageal sphincter.
sponse of the esophagus to deglutition In particular, bolus volume (1, 2), viscosity (3), and consistency (9) have incremental effects on the parameters of esopha-geal peristalsis as the bolus is changed progressively from a "dry swallow" through water to a highly viscous liquid or a solid Humans commonly drink liquids of high osmolality, but it is not known whether bolus osmolality modulates esophageal function Nasrallah and Hendrix (10) reported that a hypertonic glucose solution had no significant effects on the amplitude of esophageal contractions in 16 asymptomatic volun-teers However, esophageal contraction amplitude is not affected by alterations in many bolus attributes (3, 9), and we felt it necessary to make a closer study of the effects of an osmolar stimulus before accepting the conclusions of the previous study (10) Our study con-firms these data and expands on the previous study by documenting lack of effect on all other parameters of esophageal peristalsis and by examining boluses of widely varying osmolality
This lack of response of the esophagus to an osmolar stimulus is not unexpected Factors that have a modu-lating infiuence on esophageal peristalsis do so through alterations in resting esophageal muscle length or
Trang 3June 1989 BOLUS OSMOLALITY AND ESOPHAGEAL MOTILITY 613 stretch (preload) and/or the mass that the esophageal
muscle moves during contraction (11) The effect of
bolus viscosity appears to be mediated through
altera-tions in both preload and afterload (3), whereas the
effect of body position may be mediated through
alter-ations in afterload (12) Altering the osmolality of
in-gested liquids does not change the physical cohesiveness
of the bolus and, thus, neither preload nor afterload is
affected The lack of utility of hypertonic glucose as a
provocative test in patients with noncardiac chest pain
(10) also is explained by these considerations; the
os-molar stimulus does not stress the esophageal
muscu-lature
In summary, then, we have found that bolus
osmo-lality does not have a role in the control of human
esophageal peristalsis, and that this lack of effect is
explained by consideration of esophageal muscle
me-chanics
ACKNOWLEDGMENT
The authors express their gratitude to Charito
Ocampo for expert technical assistance
Reprint requests: Cornelius P Dooley, M.D., Section of
Gastro-enterology, Department of Medicine, USC: School of Medicine, 2025
Zonal Avenue, Los Angeles, CA 90033.
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