Esophageal manometry in pregnant and nonpregnant women ULF
ULMSTEN,
GUNNAR Malm6,
M.D.
SUNDSTRijM,
M.D.
Sweden
Esophageal and gastric tone was recorded in six pregnant and six nonpregnant women by means of a new technique for intraluminal pressure recordings. The recordings were performed in supine and standing positions, at rest, and during swallowing of saliva or water. It was found that the pregnant women had lower intraesophageai pressures but higher i c pressures compared to the nonpregnant women. In one of the pregnant women a negatkwe pressure situation was recorded between the stomach and lower esophagus. This patient atso complained of se~re heartburn when she was lying down. Gastroesophageat reflux seems to be aggravated in fxegnant women since esophageal peristalsis in these patients has lower wave speed and lower amplitude compared to nonpregnant women. (AM. J. OBSTET. GYNECOL. 132: 260, 197’9.)
IT IS well known that pregnancy is accompanied by special symptoms of the upper digestive tract such as emesis, eractions, and heartburn. Conflicting data concerning their etiology have been presented.3 Commonly, it has been assumed that during pregnancygastric tone and esophageal motility are decreased, reflections of a generalized relaxation of smooth muscles affecting also the uterus, ureters, blood vessels, and parts of the gut. Particularly in early pregnancy, the actual disorders may be aggravated by psychic factors, a conclusion supported by the high incidence of these symptoms among women who were not pleased with their pregnancies. ‘I* 5 Late in pregnancy increased intra-abdominal pressure due to the enlarged uterus has been suggested as an important factor aggravating the patients’ symptoms.’ The impact of a decreased secretion of saliva during pregnancy has also been discussed.” Esophageal motility has most commonly been studied with intraluminal pressure recordings. Varying results, most probably due to different recording techniques, have been reported from recordings during both nonpregnant and pregnant conditions.‘* j, ‘+ The purpose of the present investigation, which is
From the Departments of Obstetrics and Gynecoloa Clinical Physiology, University Hospital of Malm6. Received
for publication
Accepted
March
October
28, 1977.
13, 1978.
Reprint requests: Dr. Ulf Umsten, Department Obstetrics and Gynecology, University Hospital MalmS, Sweden.
260
and
of of Malti,
part of a series of studies of esophageal motility in women using a new investigation technique,8 was to compare esophageal motility including the action of the sphincters and the gastric tone in pregnant and nonpregnant women. blatefirl and -8 Subjects. Twelve women volunteered to take part in the study. Before the investigation they were informed of its purpose and they gave verbal consent. The stibjects were divided into two groups: one group of six nonpregnant women (NP) and one group of six pregnant women (P) at various stages of pregnancy. The subjects are listed in Table I. It should be noted that none of the nonpregnant women reported any upper digestive disorders. None of them used oral contraceptives or any other drugs. The pregnant women used only peroral iron and vitamins and, in one case, mild diuretics. One pregnant woman, Patient K. K., complained of heartburn when she was lying down. The investigation was not performed during a fasting state; the women were allowed to eat a light meal in the morning, two or three hours before the examination. Investigdion technique. Gastric tone and esophageal motility, including the activity in the upper and lower sphincter, were studied with a pressure recording technique previously described.‘Ov 8 This techaiqu.e allows recording of intraesophageal pressure at three points simultaneously. The actual technique differs from previously used methods since the measuring apertures of the recording tubes (Fig. 1) are faced toooo2-9878/78/190260+05$00.50/0
0 1978 The C. V. Mosb,
Co.
Volume Number
Table
132 3
Esophageal
manometty
261
I Nonfn-egnant Patient
P. M. U. A. I. A. B. 0. K. J. G. J. Total = 6
women (NP) Age Or) 21
33 26 xs 33
Mean = 27
Pregnant
women (P)
Patient
Age
22 27 34 25
B. 0.
K. K. A. M. M. Total
P. K. P. M. S. = 6
ward the center of the catheter; thus measuring artefacts due to intervention from esophageal mucosa are excluded and the infusion of fluid can be minimized. Each tube of the catheter was connected to a pressure transducer (EMT-35 Siemens-Elema AB, Stockholm, Sweden) and slowly perfused (3 cc. per hour) with distilled water by means of an infusion system (Intraflo Sorenson Research Co., Salt Lake City, Utah). The pressure signals were amplified by electromanometers EMT-3 11 (Siemens-Elema AB, Stockholm, Sweden) and registered on a multichannel recorder (Mingograph-81 Siemens-Elema AB, Stockholm, Sweden). Experimental procedure. The investigation started with the subjects in the supine position. The transducers were adjusted to the level of the esophagus, i.e., half way between the sternum and back. After calibration’o the recording catheter was passed nasogastrically and all the recording apertures were initially positioned in the stomach. The following procedure was then carried out twice: (1) The second or middle recording aperture of the catheter was positioned in the high-pressure zone of the lower esophageal sphincter (LES). The position was marked on the catheter to facilitate its recognition in the next run. The resting activity in the stomach, LES, and lower part of esophagus was recorded for one minute. (2) The catheter was pulled upward. The peristalsis after 15 ml. of room-temperature water was swallowed was recorded twice on each level of low and middle esophageal body, i.e., with the second measuring aperture of the catheter positioned 3 and 7 cm. proximal to LES. (3) The second recording aperture was positioned at the level of the maximal resting pressure just below the pharynx, i.e., the upper esophageal sphincter (UES). The resting activity and amplitude after 15 ml. of water was swallowed was now registered at a higher paper speed (50 mm. per second instead of the ordinarly used 5 mm. per second). The subjects were then asked to stand up and the transducers were adjusted to the level of the heart. The
Gestation (wk)
(~7)
33 30 Mean
Comment.5
33 27 28 33
Duplex Ab. habitualis Heartburn Hypertonia levis
37 34
-
Mean = 31
= 28
Table II. Esophageal nonpregnant women
peristalsis in pregnant (mean 2 S.E.M.)
and
Supine P&tah
Pregnunt
Peristaltic wave speed (cm./sec.) Lower esophagus Middle esophagus Pharynx + UES Peristaltic amplitudes (kPa) LES Lower esophagus Middle esophagus UES T test for independent p c 0.001***.
2.56* 3.22 7.25
f 0.28 2 0.53 2 0.96
2.68
2 0.41
Nonpregnant
3.67 + 0.24 3.66 f 0.68 9.38 2 0.97 2.82
+ 0.28
7.18 ‘- 0.55
7.65 + 0.71
5.74 5.63*
6.17 * 0.73 9.47 rt 1.27
f 0.45 ” 0.59
samples: p < 0.05*. p < O.Ol**,
same recording procedure was then repeated twice in the upright position. During the recording the subjects were sometimes requested to cough in order to control adequate pressure transmission from the three different recording channels of the catheter. After completion of the investigation the recording catheter was recalibrated. Since the principle definitions of the recorded parameters have been thoroughly described previously,8 they are only briefly outlined here: The resting pressures were defined as stable baseline mean pressures during the respiratory cycle unrelated to duglitation and measured in kPa above atmospheric pressure. Peristaltic wave speed was measured peak to peak calculated from knowing the distance between the catheter apertures and the paper speed. The peristaltic amplitudes were measured as the height of the peristaltic wave above atmospheric pressure. According to the new international standard they were expressed in kPa instead of centimeters of water Hz0 (1 kPa - 10 cm. H20).
Results As in the previous study which used the actual recording technique, it was noted that the recording procedure was performed without any side effects from the subjects. The measuring catheter was easily passed
262
Ulmsten and Sundstriim
c-
czEI----I 1
October Am. ,J. Ohstet.
1, 197x Gynecol.
propagated peristalsis was seen. Figs. 2 and 3 demonstrate typical records from the subjects.
Jew-
2
J
I I 3
1. Catheter used for recording of intraesophageal Pressure. Black color indicates glue. The catheter is composed of three nylon tubes glued together, except in three instances 5 cm. apart. At these pressure-sensing sections 1.2, and 3, the recording tubes are free from each other. Notice the measuring apertures facing the center of the catheter. Due to this arrangement fluid but not mucosa can move into the actual aperture. The outer diameter of the catheter is - 1.8 mm.
Fig.
into the esophagus. In technical respect the recording equipment functioned well since the calibrations before and after the recordings were in complete accordance. The mean results and deviations (S.E.M.) of the recorded parameters in the two groups of subjects, i.e., nonpregnant and pregnant women are given in Tables II and III. As can be seen in the supine position the recorded parameters in some respects differed between the nonpregnant and pregnant ,women. In that position both the peristahic wave speed and amplitude were lower in the pregnant compared to the.nonpregnant women. Thus the velocity and amplitude of the UES in the pregnant women were 7.25 cm. per second and 5.63 kPa compared to 9.38 cm. per second and 9.47 kPa in the nonpregnant women. Furthermore, the gastric tone was higher in the pregnant patients (1.11 kPa) compared to the nonpregnant (0.57 kPa) women, Moreover, the resting pressure of the lower esophagus was lower in pregnant women, -0.33 kPa compared to -0.13 in the nonpregnant subjects. In the standing position no statistically significant differences were found between pregnant and nonpregnant women. As a rule there was a distinct antegrade peristalsis both during dry swallowing and when water was swallowed. No consistent retrograde respectively non-
When esophageal function is studied in vivo by means of intraluminal pressure recording, the technique used should allow adequate evaluation of the activity at different parts of the organ simultaneously. Furthermore, it should allow proper penetration of the sphincter action which may be difficult when conventional lateral hole catheters are used for pressure recordings8 This is most deleterious since the sphincters are important biological valves. Thus the LES normally acts as an effective valve between the stomach and lower esophagus. An incompetent LES will, due to the pressure situation (an intragastric pressure higher than intraesophageal pressure), facilitate passage of gastric content into the lower esophagus. According to the results of the present investigation. the risk of gastroesophageal reflux during pregnancy must be considered increased. Thus the gastric resting pressure in pregnant patients compared to t.he nonpregnant patients was increased 1.11 kPa compared to 0.57 kPa. Simultaneously the resting pressure of the lower esophagus was lower in the pregnant women, -0.33, compared to -0.13 kPa in the nonpregnant women. Since the resting pressure in the lower sphincter was 1.57 kPa in the pregnant women and 1.52 in the nonpregnant women, the pressure balance between the stomach and lower esophagus was only +0.45 kPa ( 1.57 to 1.11) in the pregnant women, whereas in the nonpregnant women it was +0.95 kPa (1.52 to 0.57). In fact in one pregnant patient (K. K. Table I) a negative pressure situation was recorded, LES 0.76 kPa and gastric tone 1.23. This patient also complained of severe heartburn in the supine position. A decrease in peristaltic speed and amplitude may aggravate the effect of a gastroesophageal reflux. The present investigation demonstrated a lowering of the peristaltic amplitudes in the pregnant women and a decrease of the peristaltic wave speed. The latter finding is consistent with the findings of Dodds and associates2 who demonstrated the same in volunteers when increasing the intra-abdominal pressure. Nagler and Spirow’ found that a nonpropulsive motor activity of the esophagus existed far more frequently in pregnant women than in nonpregnant women. This could not be verified in the present investigation. A high incidence of hiatal hernia has been reported in pregnancy by Rigler and Enboe6 and others. When studying a group of pregnant women they detected hiatal hernia in 18 per cent of the multiparous and 12
Volume Number
132 3
Esophageal manometry
263
.cou s h Fig. 2. Pressure recording from the upper, middle, and lower esophagus. At the arrow the patient is requested to swallow 15 ml. of water. The peristaltic waves start at the upper part of the esophagus and move downward. Upper tracing = upper esophagus; middle tracing = middle esophagus; bottom tracing = lower part of esophagus. A cough affects all three recording channels equally. TO facilitate readings, the calibration is shown in centimeters of water instead of kPa; 50 cm Hz0 - 5 kPa.
Fig. 3. Pressure
recording from the upper esophageal sphincter (UES) in one of the subjects. Upper tracing denotes the pressure in the pharynx, middle tracing within the UES, and bottom tracing the pressure in the upper esophagusAt the arrow the patient is requested to swallow saliva. This results in a sharp decrease in the UES pressure indicating relaxation of the sphincter. Notice that the sphincter pressure for a short moment will pass the zero line.
Table
III.
Intragastric
and esophageal
resting
pressures
in pregnant
and nonpregnant
Supine Pwgnant Intragastric LES Lower esophagus UES LES intragastric T test for independent
kPa kPa kPa kPa kPa samples:
1.11** 1.57 -0.33 2.01 0.45 p < 0.05*,
+ + + + +
0.08 0.31 0.08 0.29 0.33
p < O.OOl**,
women
(mean -C S.E.M.)
Standing Nonpregnant 0.57 1.52 -0.13 1.99 0.95
2 c + + k
0.08 0.17 0.18 0.35 0.18
p < 0.01 l***.
Pregnant 0.42 0.63 -0.12 2.79 0.14
f 0.33 ” 0.09 LIZ 0.12 2 0.57 2 0.41
Nonpregnant 0.05 0.23 -0.44 3.51 0.04
2 f 2 2 2
0.14 0.14 0.09 0.57 0.21
264
Ulmsten
and Sundstriim
per cent of the primiparous women. It might be argued that a rise in intra-abdominal pressure induced by the pregnant uterus produces a change in the position of the stomach in its relation to the diaphragmatic hiatus. This may allow a partial passage of the lower esophageal sphincter from its normal intradiaphragmatic position into the thoracic pressure area. A proper diagnosis of hiatal hernia would require an x-ray examination which for ethical reasons could not be carried out in our pregnant patients. Concerningthe UES, the resting pressure was about the same in both the nonpregnant and pregnant women. However, the contraction amplitudes were much higher in the nonpregnant compared to the pregnant women, 9.47 kPa compared to 5.63 kPa. As seen in Table III the deviations were greater in the standing position compared to the.supine position, and no statistical differences were found between the two groups of women. It should be stressed that the change in gastric and esophageal tone by standing up could to some extent be an effect of the altered level of
REFERENCES
1. Castro, L. P.: AM. J. OBSTET. GYNECOL. 98: 1, 1967. 2. Dodds, W., Hogan, W., Stewart, E., Stef, J., and Amdorfer, R.: J. Appl. Physiol. 37: 378, 1974. 3. Hytten, F. E., and Lind, T.: Diagnostic indices in pregnancy, Ciba-Geigy Scientific Publications, Basel, 1973. 4. Kullander, S., and Sonesson, B.: Acta Endocrinol. 48: 329, 1965. 5. Nagler, R., and Spirow, H.: N. Engl. J. Med. 269: 495, 1963.
the measuring receptors in relation to the anatomical measuring points. It might be concluded that with the presently available technique, detailed studies of motility within the esophagus and the stomach can be performed both xt rest and during dynamic situations. In addition, the organs can be studied simultaneously, facilitating :I proper evaluation of the whole upper digestive tract. including the esophageal sphincters. The present investigation of the motility of the upper digestike tract reveals that there are differences between pregnant and nonpregnant women. The pregnant women have lower intraesophageal pressures but higher intragastric pressures compared to the nonpregnant women. This creates a deteriorated pressure situation facilitating gastric content to pass into the lower esophagus. Gastroesophageal reflux is further aggravated iu the pregnant women since the esophageal peristalsis in these patients has lower wave speed and lower amplitude compared to the nonpregnant women.
6. Rigler. L. G., and Enboe. II. B.: uI. Thorac. Sure.i, 4: 262, 1934. 7. Stef, J. J., Dodds, W. J., Hogan, W. J., Linehan, J. H., and Stewart, E. T.: Gastroenterology 67: 221, 1974. 8. Sundstrtim, G., and Ulmsten, U.: Stand. J. Clin. Lab. Invest. 37: 661, 1977. 9. Tuttle, S. G., Rufm, F., and Bettarello, A.: Ann. Intern. Med. 55: 292, 1961. 10. Ulmsten, U.: Stand. J. Urol. Nephrol. 9: 230, 1975. 11. Williams, N. H.: AM. J. OBSTET. GYNECOL. 42: 8 14. 194 1.
ULMSTEN,
GUNNAR Malm6,
M.D.
SUNDSTRijM,
M.D.
Sweden
Esophageal and gastric tone was recorded in six pregnant and six nonpregnant women by means of a new technique for intraluminal pressure recordings. The recordings were performed in supine and standing positions, at rest, and during swallowing of saliva or water. It was found that the pregnant women had lower intraesophageai pressures but higher i c pressures compared to the nonpregnant women. In one of the pregnant women a negatkwe pressure situation was recorded between the stomach and lower esophagus. This patient atso complained of se~re heartburn when she was lying down. Gastroesophageat reflux seems to be aggravated in fxegnant women since esophageal peristalsis in these patients has lower wave speed and lower amplitude compared to nonpregnant women. (AM. J. OBSTET. GYNECOL. 132: 260, 197’9.)
IT IS well known that pregnancy is accompanied by special symptoms of the upper digestive tract such as emesis, eractions, and heartburn. Conflicting data concerning their etiology have been presented.3 Commonly, it has been assumed that during pregnancygastric tone and esophageal motility are decreased, reflections of a generalized relaxation of smooth muscles affecting also the uterus, ureters, blood vessels, and parts of the gut. Particularly in early pregnancy, the actual disorders may be aggravated by psychic factors, a conclusion supported by the high incidence of these symptoms among women who were not pleased with their pregnancies. ‘I* 5 Late in pregnancy increased intra-abdominal pressure due to the enlarged uterus has been suggested as an important factor aggravating the patients’ symptoms.’ The impact of a decreased secretion of saliva during pregnancy has also been discussed.” Esophageal motility has most commonly been studied with intraluminal pressure recordings. Varying results, most probably due to different recording techniques, have been reported from recordings during both nonpregnant and pregnant conditions.‘* j, ‘+ The purpose of the present investigation, which is
From the Departments of Obstetrics and Gynecoloa Clinical Physiology, University Hospital of Malm6. Received
for publication
Accepted
March
October
28, 1977.
13, 1978.
Reprint requests: Dr. Ulf Umsten, Department Obstetrics and Gynecology, University Hospital MalmS, Sweden.
260
and
of of Malti,
part of a series of studies of esophageal motility in women using a new investigation technique,8 was to compare esophageal motility including the action of the sphincters and the gastric tone in pregnant and nonpregnant women. blatefirl and -8 Subjects. Twelve women volunteered to take part in the study. Before the investigation they were informed of its purpose and they gave verbal consent. The stibjects were divided into two groups: one group of six nonpregnant women (NP) and one group of six pregnant women (P) at various stages of pregnancy. The subjects are listed in Table I. It should be noted that none of the nonpregnant women reported any upper digestive disorders. None of them used oral contraceptives or any other drugs. The pregnant women used only peroral iron and vitamins and, in one case, mild diuretics. One pregnant woman, Patient K. K., complained of heartburn when she was lying down. The investigation was not performed during a fasting state; the women were allowed to eat a light meal in the morning, two or three hours before the examination. Investigdion technique. Gastric tone and esophageal motility, including the activity in the upper and lower sphincter, were studied with a pressure recording technique previously described.‘Ov 8 This techaiqu.e allows recording of intraesophageal pressure at three points simultaneously. The actual technique differs from previously used methods since the measuring apertures of the recording tubes (Fig. 1) are faced toooo2-9878/78/190260+05$00.50/0
0 1978 The C. V. Mosb,
Co.
Volume Number
Table
132 3
Esophageal
manometty
261
I Nonfn-egnant Patient
P. M. U. A. I. A. B. 0. K. J. G. J. Total = 6
women (NP) Age Or) 21
33 26 xs 33
Mean = 27
Pregnant
women (P)
Patient
Age
22 27 34 25
B. 0.
K. K. A. M. M. Total
P. K. P. M. S. = 6
ward the center of the catheter; thus measuring artefacts due to intervention from esophageal mucosa are excluded and the infusion of fluid can be minimized. Each tube of the catheter was connected to a pressure transducer (EMT-35 Siemens-Elema AB, Stockholm, Sweden) and slowly perfused (3 cc. per hour) with distilled water by means of an infusion system (Intraflo Sorenson Research Co., Salt Lake City, Utah). The pressure signals were amplified by electromanometers EMT-3 11 (Siemens-Elema AB, Stockholm, Sweden) and registered on a multichannel recorder (Mingograph-81 Siemens-Elema AB, Stockholm, Sweden). Experimental procedure. The investigation started with the subjects in the supine position. The transducers were adjusted to the level of the esophagus, i.e., half way between the sternum and back. After calibration’o the recording catheter was passed nasogastrically and all the recording apertures were initially positioned in the stomach. The following procedure was then carried out twice: (1) The second or middle recording aperture of the catheter was positioned in the high-pressure zone of the lower esophageal sphincter (LES). The position was marked on the catheter to facilitate its recognition in the next run. The resting activity in the stomach, LES, and lower part of esophagus was recorded for one minute. (2) The catheter was pulled upward. The peristalsis after 15 ml. of room-temperature water was swallowed was recorded twice on each level of low and middle esophageal body, i.e., with the second measuring aperture of the catheter positioned 3 and 7 cm. proximal to LES. (3) The second recording aperture was positioned at the level of the maximal resting pressure just below the pharynx, i.e., the upper esophageal sphincter (UES). The resting activity and amplitude after 15 ml. of water was swallowed was now registered at a higher paper speed (50 mm. per second instead of the ordinarly used 5 mm. per second). The subjects were then asked to stand up and the transducers were adjusted to the level of the heart. The
Gestation (wk)
(~7)
33 30 Mean
Comment.5
33 27 28 33
Duplex Ab. habitualis Heartburn Hypertonia levis
37 34
-
Mean = 31
= 28
Table II. Esophageal nonpregnant women
peristalsis in pregnant (mean 2 S.E.M.)
and
Supine P&tah
Pregnunt
Peristaltic wave speed (cm./sec.) Lower esophagus Middle esophagus Pharynx + UES Peristaltic amplitudes (kPa) LES Lower esophagus Middle esophagus UES T test for independent p c 0.001***.
2.56* 3.22 7.25
f 0.28 2 0.53 2 0.96
2.68
2 0.41
Nonpregnant
3.67 + 0.24 3.66 f 0.68 9.38 2 0.97 2.82
+ 0.28
7.18 ‘- 0.55
7.65 + 0.71
5.74 5.63*
6.17 * 0.73 9.47 rt 1.27
f 0.45 ” 0.59
samples: p < 0.05*. p < O.Ol**,
same recording procedure was then repeated twice in the upright position. During the recording the subjects were sometimes requested to cough in order to control adequate pressure transmission from the three different recording channels of the catheter. After completion of the investigation the recording catheter was recalibrated. Since the principle definitions of the recorded parameters have been thoroughly described previously,8 they are only briefly outlined here: The resting pressures were defined as stable baseline mean pressures during the respiratory cycle unrelated to duglitation and measured in kPa above atmospheric pressure. Peristaltic wave speed was measured peak to peak calculated from knowing the distance between the catheter apertures and the paper speed. The peristaltic amplitudes were measured as the height of the peristaltic wave above atmospheric pressure. According to the new international standard they were expressed in kPa instead of centimeters of water Hz0 (1 kPa - 10 cm. H20).
Results As in the previous study which used the actual recording technique, it was noted that the recording procedure was performed without any side effects from the subjects. The measuring catheter was easily passed
262
Ulmsten and Sundstriim
c-
czEI----I 1
October Am. ,J. Ohstet.
1, 197x Gynecol.
propagated peristalsis was seen. Figs. 2 and 3 demonstrate typical records from the subjects.
Jew-
2
J
I I 3
1. Catheter used for recording of intraesophageal Pressure. Black color indicates glue. The catheter is composed of three nylon tubes glued together, except in three instances 5 cm. apart. At these pressure-sensing sections 1.2, and 3, the recording tubes are free from each other. Notice the measuring apertures facing the center of the catheter. Due to this arrangement fluid but not mucosa can move into the actual aperture. The outer diameter of the catheter is - 1.8 mm.
Fig.
into the esophagus. In technical respect the recording equipment functioned well since the calibrations before and after the recordings were in complete accordance. The mean results and deviations (S.E.M.) of the recorded parameters in the two groups of subjects, i.e., nonpregnant and pregnant women are given in Tables II and III. As can be seen in the supine position the recorded parameters in some respects differed between the nonpregnant and pregnant ,women. In that position both the peristahic wave speed and amplitude were lower in the pregnant compared to the.nonpregnant women. Thus the velocity and amplitude of the UES in the pregnant women were 7.25 cm. per second and 5.63 kPa compared to 9.38 cm. per second and 9.47 kPa in the nonpregnant women. Furthermore, the gastric tone was higher in the pregnant patients (1.11 kPa) compared to the nonpregnant (0.57 kPa) women, Moreover, the resting pressure of the lower esophagus was lower in pregnant women, -0.33 kPa compared to -0.13 in the nonpregnant subjects. In the standing position no statistically significant differences were found between pregnant and nonpregnant women. As a rule there was a distinct antegrade peristalsis both during dry swallowing and when water was swallowed. No consistent retrograde respectively non-
When esophageal function is studied in vivo by means of intraluminal pressure recording, the technique used should allow adequate evaluation of the activity at different parts of the organ simultaneously. Furthermore, it should allow proper penetration of the sphincter action which may be difficult when conventional lateral hole catheters are used for pressure recordings8 This is most deleterious since the sphincters are important biological valves. Thus the LES normally acts as an effective valve between the stomach and lower esophagus. An incompetent LES will, due to the pressure situation (an intragastric pressure higher than intraesophageal pressure), facilitate passage of gastric content into the lower esophagus. According to the results of the present investigation. the risk of gastroesophageal reflux during pregnancy must be considered increased. Thus the gastric resting pressure in pregnant patients compared to t.he nonpregnant patients was increased 1.11 kPa compared to 0.57 kPa. Simultaneously the resting pressure of the lower esophagus was lower in the pregnant women, -0.33, compared to -0.13 kPa in the nonpregnant women. Since the resting pressure in the lower sphincter was 1.57 kPa in the pregnant women and 1.52 in the nonpregnant women, the pressure balance between the stomach and lower esophagus was only +0.45 kPa ( 1.57 to 1.11) in the pregnant women, whereas in the nonpregnant women it was +0.95 kPa (1.52 to 0.57). In fact in one pregnant patient (K. K. Table I) a negative pressure situation was recorded, LES 0.76 kPa and gastric tone 1.23. This patient also complained of severe heartburn in the supine position. A decrease in peristaltic speed and amplitude may aggravate the effect of a gastroesophageal reflux. The present investigation demonstrated a lowering of the peristaltic amplitudes in the pregnant women and a decrease of the peristaltic wave speed. The latter finding is consistent with the findings of Dodds and associates2 who demonstrated the same in volunteers when increasing the intra-abdominal pressure. Nagler and Spirow’ found that a nonpropulsive motor activity of the esophagus existed far more frequently in pregnant women than in nonpregnant women. This could not be verified in the present investigation. A high incidence of hiatal hernia has been reported in pregnancy by Rigler and Enboe6 and others. When studying a group of pregnant women they detected hiatal hernia in 18 per cent of the multiparous and 12
Volume Number
132 3
Esophageal manometry
263
.cou s h Fig. 2. Pressure recording from the upper, middle, and lower esophagus. At the arrow the patient is requested to swallow 15 ml. of water. The peristaltic waves start at the upper part of the esophagus and move downward. Upper tracing = upper esophagus; middle tracing = middle esophagus; bottom tracing = lower part of esophagus. A cough affects all three recording channels equally. TO facilitate readings, the calibration is shown in centimeters of water instead of kPa; 50 cm Hz0 - 5 kPa.
Fig. 3. Pressure
recording from the upper esophageal sphincter (UES) in one of the subjects. Upper tracing denotes the pressure in the pharynx, middle tracing within the UES, and bottom tracing the pressure in the upper esophagusAt the arrow the patient is requested to swallow saliva. This results in a sharp decrease in the UES pressure indicating relaxation of the sphincter. Notice that the sphincter pressure for a short moment will pass the zero line.
Table
III.
Intragastric
and esophageal
resting
pressures
in pregnant
and nonpregnant
Supine Pwgnant Intragastric LES Lower esophagus UES LES intragastric T test for independent
kPa kPa kPa kPa kPa samples:
1.11** 1.57 -0.33 2.01 0.45 p < 0.05*,
+ + + + +
0.08 0.31 0.08 0.29 0.33
p < O.OOl**,
women
(mean -C S.E.M.)
Standing Nonpregnant 0.57 1.52 -0.13 1.99 0.95
2 c + + k
0.08 0.17 0.18 0.35 0.18
p < 0.01 l***.
Pregnant 0.42 0.63 -0.12 2.79 0.14
f 0.33 ” 0.09 LIZ 0.12 2 0.57 2 0.41
Nonpregnant 0.05 0.23 -0.44 3.51 0.04
2 f 2 2 2
0.14 0.14 0.09 0.57 0.21
264
Ulmsten
and Sundstriim
per cent of the primiparous women. It might be argued that a rise in intra-abdominal pressure induced by the pregnant uterus produces a change in the position of the stomach in its relation to the diaphragmatic hiatus. This may allow a partial passage of the lower esophageal sphincter from its normal intradiaphragmatic position into the thoracic pressure area. A proper diagnosis of hiatal hernia would require an x-ray examination which for ethical reasons could not be carried out in our pregnant patients. Concerningthe UES, the resting pressure was about the same in both the nonpregnant and pregnant women. However, the contraction amplitudes were much higher in the nonpregnant compared to the pregnant women, 9.47 kPa compared to 5.63 kPa. As seen in Table III the deviations were greater in the standing position compared to the.supine position, and no statistical differences were found between the two groups of women. It should be stressed that the change in gastric and esophageal tone by standing up could to some extent be an effect of the altered level of
REFERENCES
1. Castro, L. P.: AM. J. OBSTET. GYNECOL. 98: 1, 1967. 2. Dodds, W., Hogan, W., Stewart, E., Stef, J., and Amdorfer, R.: J. Appl. Physiol. 37: 378, 1974. 3. Hytten, F. E., and Lind, T.: Diagnostic indices in pregnancy, Ciba-Geigy Scientific Publications, Basel, 1973. 4. Kullander, S., and Sonesson, B.: Acta Endocrinol. 48: 329, 1965. 5. Nagler, R., and Spirow, H.: N. Engl. J. Med. 269: 495, 1963.
the measuring receptors in relation to the anatomical measuring points. It might be concluded that with the presently available technique, detailed studies of motility within the esophagus and the stomach can be performed both xt rest and during dynamic situations. In addition, the organs can be studied simultaneously, facilitating :I proper evaluation of the whole upper digestive tract. including the esophageal sphincters. The present investigation of the motility of the upper digestike tract reveals that there are differences between pregnant and nonpregnant women. The pregnant women have lower intraesophageal pressures but higher intragastric pressures compared to the nonpregnant women. This creates a deteriorated pressure situation facilitating gastric content to pass into the lower esophagus. Gastroesophageal reflux is further aggravated iu the pregnant women since the esophageal peristalsis in these patients has lower wave speed and lower amplitude compared to the nonpregnant women.
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