Lower esophageal sphincter pressure as an index of gastroesophageal acid reflux

The purpose of this study was to determine the relationship of lower esophageal sphincter (LES) pressure and the volume of acid placed into the stomach required to induce gastroesophageal reflux in man. LES pressure was recorded continuously and by station pull-through by three radially oriented catheters in both symptomatic and asymptomatic subjects during the graded infusions of 0.1 N HCl acid into the stomach. Sumptomatic subjects had a mean LES pressure of 7.5±0.7 mm Hg and refluxed at a volume of 140.0±21.0 ml. Fifty-five percent of asymptomatic subjects refluxed at a mean volume of 380.0±24.7 ml, and had a mean LES pressure of 13.8±0.4 mm Hg. Asymptomatic nonrefluxers at a volume of 500 ml of 0.1 HCL acid had a mean LES pressure of 18.9±1.1 mm Hg. The mean LES pressure and acid volumes showed statistical significance between the three groups (P<0.01). There was an excellent overall correlation between LES pressure and acid volume required to produce reflux in all subjects (r=0.91,P<0.001). Following reflux, asymptomatic but not symptomatic subjects showed a significant increase in LES pressure. These studies suggest that: (1) LES pressure does provide an accurate index of the gastroesophageal antireflux mechanism, provided that acid volume is considered; and (2) asymptomatic subjects showing acid reflux have higher LES pressures, reflux at higher volumes, and develop an LES contractile response after the reflux episode.This work was supported by a grant from the Smith Kline & French Laboratories, Philadelphia, Pennsylvania.     

Antireflux surgery for symptomatic gastroesophageal reflux

To determine the effects of Nissen fundoplication upon the symptoms of reflux and the diagnostic tests employed to evaluate reflux and to examine the relationship between gastroesophageal reflux and lower esophageal sphincter pressure before and after fundoplication, 10 patients with symptomatic reflux were studied before and after operation. Clinical evaluation, barium esophagography, endoscopy with mucosal biopsy, esophageal manometry, acid-perfusion and acid-reflux testing, and gastroesophageal scintiscanning were performed on each patient before and after surgery. Following fundoplication, marked symptomatic, radiographic, endoscopic, and histologic improvement was observed. Serial acid-reflux tests at increasing gastroesophageal pressure gradients returned to normal after surgery. Lower-esophageal-sphincter (LES) pressure increased from 8.2±1.3 to 12.0±1.5 mm Hg (P<0.01). In addition, surgery resulted in a significant decrease in the gastroesophageal reflux index from 17.4±2.4 to 2.7±1.1% (P<0.001). Surprisingly, the pre- and postoperative resting LES pressures did not correlate significantly with corresponding gastroesophageal reflux indices for individual patients. We conclude that increased LES pressure alone does not explain adequately the functional and clinical improvement which follows fundoplication.     

Clinical and manometric findings in benign peptic strictures of the esophagus

To determine the possible factors that may contribute to the development of peptic stricture of the esophagus, clinical and manometric features were compared in patients with symptomatic gastroesophageal reflux and those with peptic strictures of the esophagus. Patients with stricture were older and had a longer duration of heartburn than patients without a stricture. Most importantly, patients with stricture had a more marked decrease in lower esophageal sphincter (LES) pressure, 4.9±0.5 mm Hg, than patients without a stricture, 7.5±0.6 mm Hg, P<0.01. The LES pressure in all patients with stricture was below 8 mm Hg, and did not overlap with normal values. Patients with stricture had either a nonspecific motor abnormality or aperistalsis (64%), compared to patients with symptomatic reflux (32%), P<0.05. Thus, peptic stricture of the esophagus is commonly associated with a long duration of reflux symptoms in patients with a very low LES pressure and esophageal motor disorder.     

Cholinergic stimulation of the lower esophageal sphincter in patients with vagotomy and antrectomy

Recently cholinergic stimulation of the lower esophageal sphincter (LES) with bethanechol has been shown to be effective in the treatment of chronic gastroesophageal reflux. Since chronic reflux and esophagitis also occur in patients with vagotomy and antrectomy, we studied the effect of bethanechol on sphincter pressure in 10 patients who had had vagotomy and antrectomy. Both subcutaneous (0.08 mg/kg) and oral (25 mg) administration of bethanechol caused significant increases in LES pressure in these patients. In addition, both subcutaneous and oral administration of bethanechol elevated hypotensive sphincter pressures to normal levels. Orally administered bethanechol produced a sustained increase in LES pressure throughout a 90-min study period. These studies suggest that cholinergic stimulation of the LES with bethanechol may be of therapeutic benefit in vagotomized and antrectomized patients with gastroesophageal reflux.     

Gastric distention: a mechanism for postprandial gastroesophageal reflux

The occurrence of gastroesophageal reflux after meals may be related to an increase in the rate of transient lower esophageal sphincter (LES) relaxations, the mechanisms of which are not understood. We investigated the effects of gastric distention on LES pressure in 16 normal subjects and 17 patients with gastroesophageal reflux disease. Intraluminal pressure was measured in the gastric fundus, LES, and esophageal body with a manometric catheter incorporating a sleeve device. Gastric distention was performed by injecting 0, 250, 500, or 750 ml of air in randomized order into a balloon and maintaining each stimulus for 15 min. Gastric distention did not significantly alter resting LES pressure in either group. During the basal period the rate of transient LES relaxation in the reflux patients (1.1 +/- 0.4 per 15 min) was greater than that in the normal subjects (0.6 +/- 0.1 per 15 min). Gastric distention resulted in a significant threefold to fourfold increase in the rate of transient LES relaxations in both groups. The reflux patients had a significantly greater proportion of complete relaxations (87%) than did the normal subjects (73%). We conclude that gastric distention, by significantly increasing the rate of transient LES relaxations in both normal subjects and patients with gastroesophageal reflux disease, may contribute to the postprandial increase in gastroesophageal reflux.     

Provocation of transient lower esophageal sphincter relaxations by meals in patients with symptomatic gastroesophageal reflux

The effect of a meal on the rate of transient lower esophageal sphinter (LES) relaxations and patterns of gastroesophageal reflux was investigated in 49 patients referred for evaluation of gastroesophageal reflux. Esophageal motility and pH were recorded concurrently before and after a standard meal. In the patients with symptomatic reflux, the meal induced a four-to sevenfold increase in the gastroesophageal reflux through two mechanisms: a four-to fivefold increase in the rate of transient LES relaxations and an increase in the proportion of transient LES relaxations accompanied by reflux from 47% to 68^. Overall the rate of reflux episodes that occurred by mechanisms other than transient LES relaxation did not increase significantly. An exception to these findings were those in six patients with chronically absent basal LES pressure in whom transient LES relaxations could not be scored. In these patients, reflux increased postprandially through mechanisms other than transient LES relaxation. These findings confirm the pivotal importance of transient LES relaxations in the pathogenesis of gastroesophageal reflux.     

Role of CCK(A) receptors in postprandial lower esophageal sphincter function in morbidly obese subjects

To reduce weight, some morbidly obese patients are treated with an intragastric balloon, often resulting in increased reflux symptoms. As transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism underlying reflux and can be reduced by cholecystokinin-A (CCK_A) blockade, we hypothesized that the CCK_A-receptor antagonist loxiglumide could reduce gastroesophageal reflux in these subjects. Postprandial manometric studies were performed in 12 obese subjects during infusion of placebo or loxiglumide. Before balloon placement, loxiglumide did not significantly reduce the rate of TLESRs but attenuated the postprandial decrease in LES pressure. After 10 weeks of balloon treatment, loxiglumide significantly reduced the rate of TLESRs. Postprandial LES pressure was significantly increased, whereas the meal-induced decrease in LES pressure was absent. Neither loxiglumide nor balloon placement affected gastroesophageal reflux. In conclusion, CCK_A receptors play an important role in post-prandial LES pressure decrease and are involved in the reflex pathway underlying the triggering of TLESRs, at least after balloon placement.     

Impact of endoscopic suturing of the gastroesophageal junction on lower esophageal sphincter function and gastroesophageal reflux in patients with reflux disease

OBJECTIVES: Plication of the gastroesophageal junction by endoscopic suturing has been reported to improve symptoms and reduce acid exposure in patients with gastroesophageal reflux disease (GERD). The mechanisms underlying these effects are not well defined. The aims of our study were to determine the impact of endoscopic suturing of the gastroesophageal junction on lower esophageal sphincter (LES) function in patients with GERD. METHODS: In 15 patients (7 males) with GERD (heartburn, % time esophageal pH < 4 greater than 4%, +/- history of erosive esophagitis within 6 months), two plications were performed circumferentially 1 cm below the gastroesophageal junction. Endoscopy and combined postprandial esophageal manometry and pH monitoring were performed before and 6 months after treatment; 24-h ambulatory pH monitoring and symptom assessment were also performed before, and at 6 and 12 months after treatment. RESULTS: Six months after treatment, the rate of transient LES relaxations (tLESRs) was decreased by 37% (p < 0.05) and basal LES pressure had increased from 4.3 +/- 2.2 mmHg to 6.2 +/- 2.1 mmHg (p < 0.05). The rate of postprandial reflux events and acid exposure time were not altered. Endoscopic suturing significantly reduced 24-h esophageal acid exposure from 9.6% (9.0-12.1) to 7.4% (3.9-10.1) at 6 months, due predominantly to a reduction in upright acid exposure. The reduction in total 24-h acid exposure was sustained to 12 months. At repeat endoscopy, only one plication was evident in 6 patients (40%) at 6 months. Seven patients (47%) remained off medications at 6 and 12 months follow-up. CONCLUSIONS: In patients with GERD, endoscopic suturing of the gastroesophageal junction results in a reduction in the rate of tLESRs, and an increase in basal LES pressure. These changes in LES function result in only a modest reduction in gastroesophageal reflux.     

The hypertensive lower esophageal sphincter

Controversy exists as to whether the hypertensive lower esophageal sphincter (HLES) represents a clinical motility disorder of the esophagus or is merely the right-sided expression of a normal distribution curve. In the present study we describe 16 patients with HLES, defined as a lower esophageal sphincter (LES) pressure of 40 mm Hg (mean +3sd of controls) with normal peristalsis. All of the patients suffered from chest pain and nine from dysphagia. Delayed bolus transit at the gastroesophageal junction was demonstrated in four patients by radiography. Manometric studies showed that during swallowing the LES residual pressures were significantly greater (9.2±5.0 mm Hg) than observed in normal controls (1.8±2.2 mmHg) (mean±1sd). However, the percent LES relaxation in patients did not differ significantly from controls. Clinical improvement was associated with pharmacological or mechanical reduction of resting LES pressure with an accompanying fall in the nadir pressure. These observations suggest that HLES may have clinical and pathophysiological significance and that evidence for the entity should be sought during manometric studies in the clinical laboratory.     

Excess gastroesophageal reflux in patients with hiatus hernia is caused by mechanisms other than transient LES relaxations

BACKGROUND & AIMS: Esophageal acid exposure is higher in gastroesophageal reflux disease (GERD) patients with hiatus hernia than in those without. We investigated the effect of a sliding hiatus hernia on the mechanisms underlying spontaneous gastroesophageal reflux over 24 hours. METHODS: Twelve GERD patients with and 10 GERD patients without hiatus hernia were studied for 24 hours. Combined esophageal pH and manometric recordings of the pharynx, lower esophageal sphincter (LES), and stomach were performed using a multiple-lumen assembly incorporating a Dent sleeve connected to a portable water-perfused manometric system and a pH glass electrode. RESULTS: Patients with hiatus hernia had greater esophageal acid exposure (7.6% vs. 3.3%; P < 0.01) and more reflux episodes (3.1 vs. 1.8/h; P < 0.001) than those without. LES pressure, the incidence of transient LES relaxations (TLESRs), and the proportion of TLESRs associated with acid reflux were comparable in both groups. Both groups had equal numbers of reflux episodes associated with TLESRs and swallow-associated prolonged LES relaxations. Patients with hiatus hernia had more reflux associated with low LES pressure, swallow-associated normal LES relaxations, and straining during periods with low LES pressure. CONCLUSIONS: The excess reflux in GERD patients with hiatus hernia compared with those without is caused by malfunction of the gastroesophageal barrier during low LES pressure, swallow-associated normal LES relaxations, deep inspiration, and straining.     

Correlation of esophageal pH and motor abnormalities with endoscopic severity of reflux esophagitis

Motility abnormalities, common in gastroesophageal reflux disease, are likely to be related to endoscopic esophagitis. We studied pH and manometry parameters in relation to the severity of esophagitis. Forty-seven patients with symptomatic gastroesophageal reflux disease for > 3 months were evaluated by: (i) endoscopy (grading of esophagitis by Savary-Miller classification); (ii) mucosal biopsy; (iii) manometry; and (iv) 24-h pH-metry. We found Savary-Miller's grades of: 0 (9 patients out of 47), I (16/47), II (16/47), III (4/47), IV (2/47). Distal esophageal contraction amplitude was lower in severe (grade II to IV) as compared with mild (grade 0 and I) esophagitis (49 [7-182] versus 83 [27-196] mmHg [P = 0.001]). The length and pressure in the lower esophageal sphincter (LES), duration and velocity of contraction in the body, number of episodes of reflux and long-duration reflux, longest reflux, median pH, per cent of time with pH < 4 and DeMeester scores were not significantly different between the two groups. The area under pH 4 showed a negative correlation with LES pressure and amplitude of distal esophageal contractions. We conclude that higher endoscopic grades of esophagitis are associated with lower amplitude of contraction in distal esophagus. Lower LES pressure and distal esophageal contraction amplitude are associated with greater area under curve for pH below 4.     

High vasoactive intestinal polypeptide plasma levels in patients with Barrett's esophagus

We have evaluated the correlation between vasoactive intestinal polypeptide (VIP) plasma concentration and severity of gastroesophageal reflux in patients with Barrett's esophagus and the possible differences in the VIP values of these patients compared with healthy volunteers. We also evaluated the relation between VIP plasma concentration and lower esophageal sphincter (LES) pressure in 24 patients with Barrett's esophagus. The mean VIP plasma concentration in 14 patients with severe gastroesophageal reflux was 25.6 +/- 0.75 pg/ml, significantly higher than the mean value observed in 10 patients with moderate reflux (18.9 +/- 0.67 pg/ml) (p less than 0.01). The mean LES resting pressure was significantly lower in the group of patients with severe gastroesophageal reflux than that observed in patients with moderate reflux (3 +/- 0.64 and 10.3 +/- 0.69 mm Hg, respectively; p less than 0.01). The mean VIP plasma concentration in 11 healthy volunteers (20.6 +/- 0.65 pg/ml) was significantly lower than the mean value observed in the subgroup of patients with severe gastroesophageal reflux (p less than 0.01). VIP values in patients with moderate reflux were not significantly different from those observed in our volunteers. There was a significant correlation between LES pressure and VIP plasma level (r = -0.9253; p less than 0.01). In conclusion, it is possible that the decreased LES resting pressure observed in patients with Barrett's esophagus and severe gastroesophageal reflux may be due to impairment of the VIPergic innervation, resulting in an increased local VIP release with possible overflow to peripheral plasma.     

Esophageal manometric changes and gastroesophageal reflux symptoms after distal gastrectomy for gastric cancer

BACKGROUND/AIMS: Gastroesophageal reflux is known to be a common complication after gastrectomy. However, its mechanism is not completely understood. We investigated the effects of distal gastrectomy for gastric cancer on the lower esophageal sphincter (LES) and esophageal motility. METHODOLOGY: In 18 patients who underwent distal gastrectomy reconstructed with Billroth I method for gastric cancer, esophageal motility and LES function were evaluated by means of a low-compliance manometric system. The LES pressure was determined by a rapid pull-through technique. Endoscopy before and after operation determined presence or absence of esophagitis and hiatus hernia. RESULTS: No significant differences were observed in esophageal contractile amplitudes before and after distal gastrectomy. After distal gastrectomy, five patients had reflux symptoms of heartburn and regurgitation; 11 had none. Endoscopy revealed esophagitis after distal gastrectomy in two patients with reflux symptoms and one patient without reflux symptoms. The LES pressure in patients with reflux symptoms decreased significantly after distal gastrectomy (before gastrectomy: 26.1 +/- 1.1 mmHg, after distal gastrectomy: 15.3 +/- 3.5 mmHg, p<0.05). There was no significant change in patients without reflux symptoms. CONCLUSIONS: This study demonstrated that LES pressure after distal gastrectomy in patients with reflux symptoms was significantly lower than that before gastrectomy. This result suggested that LES pressure decrease plays an important role in development of gastroesophageal reflux after distal gastrectomy reconstruction with the Billroth I method.     

Comparison of Lower Esophageal Sphincter Manometrics and Gastroesophageal Reflux Measured by 24-Hour pH Recording

We compared lower esophageal sphincter (LES) pressures to parameters of acid reflux measured during 24-h pH monitoring in 81 patients being evaluated for possible reflux disease. Mid-respiratory LES pressures were significantly higher (p less than 0.05) in patients with normal amounts of reflux than in those with abnormal reflux. This difference did not occur with LES pressure measured by end-expiratory station pull-through (SPT) or rapid pull-through (RPT). There was no significant difference in total length or intra-abdominal portion of LES between the two groups. However, the product of LES pressure and total LES length was greater (p less than 0.05) for patients with normal reflux than for these with abnormal reflux. No difference was noted in the percentage of abnormal contractions in the distal esophagus between groups. These studies support the following conclusions: 1) LES pressure may be a more important protective mechanism against reflux than LES length. 2) Mid-respiratory SPT technique appears to identify the LES antireflux barrier better than either end-expiratory SPT or RPT techniques. 3) Acid exposure time seems to be a better measure of gastroesophageal reflux than the number of reflux episodes.     

Esophageal body length, lower esophageal sphincter length, position and pressure in health and disease

We compared esophageal dimensions in control subjects and patients with differing motility disorders and severities of reflux disease. Patients (1108) and healthy controls (36) underwent manometry and 24-h pH monitoring. Subjects were grouped according to pH and manometry data into seven groups. Mean (s.e.m.) esophageal body length is greatest in achalasia [22.41 (0.27) cm] and least in reflux disease [20.06 (0.13) cm, p < 0.05]. Lower esophageal sphincter (LES) pressure is greatest in achalasia [17.46 (1.06) mmHg] and least in reflux disease [6.57 (0.24) mmHg, p < 0.05]. LES length is least in achalasia patients and control subjects. The ratio of intra-abdominal to intrathoracic LES is greatest in achalasia (1.29), no reflux and normal motility group, and controls and least in reflux disease (1.04, p < 0.05). In conclusion, esophageal body length is greatest in achalasia and least in reflux disease. This is associated with caudal movement of the LES in achalasia and cranial movement of the LES in reflux disease, relative to the diaphragm.     

Upright versus supine reflux in gastroesophageal reflux disease

BACKGROUND: Postural measures are early recommendations in the management of heartburn, and are aimed at preventing acid reflux through an incompetent lower esophageal sphincter (LES). However, LES incompetence is found in only a minority of patients, and transient LES relaxations, primarily in the upright position, are currently recognized as the main pathophysiological abnormality in gastroesophageal reflux disease (GERD). We investigated the importance of supine acid reflux in patients with GERD. METHODS: Upon review of their clinical, manometric, pH monitoring and endoscopic characteristics, 85 patients with reflux symptoms were classified into three groups: Group A (n=22), consisting of symptomatic patients without esophagitis or pathological reflux; group B (n=38), symptomatic patients with reflux but no endoscopic esophagitis; and group C (n=25), symptomatic patients with both ulcerative or complicated esophagitis and pathological reflux. RESULTS: All groups were similar in age distribution. Groups B and C had a higher prevalence of hiatal hernia and reflux symptoms. Manometry revealed similar LES pressures in groups A and B, but lower LES pressure in group C (P < 0.005). In groups A and B, supine reflux, in terms of percentage of time with pH < 4, was less pronounced than upright reflux (P < 0.0001). In contrast, group C supine reflux was as pronounced as the upright reflux. CONCLUSIONS: The majority of patients reflux in the upright position. Only patients with complicated esophagitis have significant bipositional acid reflux. These findings suggest that unless the patient has severe reflux disease, postural measures may not be indicated.     

Identification and mechanism of delayed esophageal acid clearance in subjects with hiatus hernia

To determine if hiatus hernia (HH) contributes to the delayed clearance of acid from the esophagus in patients with gastroesophageal reflux (GER), we performed simultaneous esophageal pH recordings and radionuclide studies in three study populations: 12 GER patients with HH, 5 GER patients with no HH, and 8 subjects with HH but no GER symptoms. Acid clearance was measured at 5 cm. above the manometrically located lower esophageal sphincter (LES) after injecting a 15-ml. bolus of 0.1 N HCl at 15 cm. above the LES. The acid was labeled with 200 mu Ci of 99mTc-sulfur colloid. Acid clearance was also measured at 10 cm. above the LES after injection of a 15-ml. bolus of 0.1 N HCl at 20 cm. above the LES. Acid clearance at 5 cm. above the LES was faster in GER patients with no HH compared to GER patients with HH and asymptomatic HH subjects. Acid clearance was faster at 10 cm. than 5 cm. above the LES in all HH and non-HH subjects studied. In non-HH subjects, each swallow resulted in an increase in pH (a monophasic pH response) at 5 and 10 cm. above the LES. In symptomatic as well as asymptomatic HH subjects, swallows resulted in an initial fall followed by a rise in pH at 5 cm. above the LES (a biphasic pH response). Radionuclide studies showed reflux of the isotope-labeled acid into the esophagus followed by clearance (a biphasic response) accompanying swallows in 15 of the 20 HH subjects. Swallow-induced reflux was not detected by radionuclide scanning in non-HH subjects. Based on these observations, we conclude that during acid clearance a small amount of acid is trapped in the HH sac and refluxes into the esophagus during subsequent swallows when there is relaxation of the LES, and these repeated episodes of acid reflux from the HH account for the delayed acid clearance observed in GER patients with HH.     

Effect of sodium valproate on esophageal motility in healthy subjects and patients with gastroesophageal reflux

BACKGROUND: There is experimental evidence to show that upper gastrointestinal tract motility is influenced by a GABAergic mechanism. Sodium valproate acts as a GABA agonist, and has been proven to affect the human internal anal sphincter. The aim of this study was to evaluate any possible effect of sodium valproate on esophageal motility in healthy subjects and patients with gastroesophageal reflux disease (GERD). METHODS: Ten healthy volunteers (4 M, 6 F; age range: 20-61 years) and 12 patients (4 M, 8 F; age range: 25-70 years) with GERD were included in the study. Standard esophageal manometry and ambulatory 24-h esophageal pH monitoring were performed before and 5 days after oral administration of sodium valproate (400 mg four times per day). Main measurements included a) lower esophageal sphincter (LES) resting pressure and amplitude and duration of peristalsis at 5, 10 and 15 cm proximal to LES, and b) percentage of time with esophageal pH <4 and number of reflux episodes. RESULTS: Sodium valproate (i) significantly increased LES resting pressure in both groups (P<0.05), without affecting either the LES postdeglutition relaxation or any of the parameters of the esophageal peristaltic activity, (ii) significantly reduced the number of reflux episodes at the postprandial period in both healthy subjects (P=0.02) and reflux patients without hiatal hernia (P=0.04) and (iii) the time percentage with esophageal pH <4 at the postprandial period in reflux patients (P=0.01). CONCLUSIONS: Sodium valproate increases normal and reduced tonic activity of the human LES and reduces the number of reflux episodes in health and GERD. This action could be attributed to a central GABAergic mechanism.     

Factors that influence induction of gastroesophageal reflux in normal human subjects

Findings from recent studies indicate that transient relaxation of the lower esophageal sphincter (LES) is an important contributory mechanism to spontaneous episodes of gastroesophageal reflux (GER) in normal subjects as well as in patients with reflux esophagitis. Our study aim was to evaluate the interrelationship between reduction of LES pressure and elevation of intraabdominal pressure in the induction of GER in healthy subjects. Seven volunteers were studied supine after gastric loading with 0.1 N HCl. A pH probe recorded acid GER. Leg raising (LR) or abdominal compression (AC) were used as stress maneuvers to increase intraabdominal pressure, either alone or in combination with stimuli that concurrently lowered LES pressure, namely multiple rapid swallows (RS) or intraesophageal balloon distention (BD). Each individual stimulus and stimulus combination was tested three times, giving a total of 24 test maneuvers per subject. The test maneuvers elicited 2-12 GERs in each subject. The GER incidence for single maneuvers was: AC, 0%; LR, 0%; RS, 19%; and BD, 24%. LR in combination with RS or BD did not increase the incidence of GER above that induced by RS or BD alone. In contrast, AC concurrent with RS and BD increased the incidence of GER to 52% and 81%, respectively. For all test conditions, a prerequisite for the occurrence of GER was a fall in LES pressure to a minimal value of 3 mm Hg or less. GER never occurred when LES pressure was greater than or equal to 4 mm Hg, even during intervals of increased intraabdominal pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Colonoscopy without Sedation

The results of ambulatory 24-h esophageal pH monitoring in 67 patients with gastroesophageal reflux symptoms (endoscopic esophagitis, n = 44; normal endoscopy, n = 23) were compared with those of 27 normal subjects without reflux symptoms. Patients with reflux symptoms had significantly increased gastroesophageal reflux compared with normal subjects. Acid reflux time was significantly (p < 0.001) correlated with the severity of endoscopic esophagitis. Linear discriminant analysis was used to differentiate, for each reflux variable, between patients and controls. When the percentage of overall time at pH below 4 was used as a single determinant of gastroesophageal reflux, the sensitivity and specificity were 81% and 85%, respectively, with 4% as upper limit of normal. Pathologic reflux was found in 61% of the patients with negative endoscopy. Long-term ambulatory pH-metry is of clinical value in detecting pathologic reflux in symptomatic patients with negative endoscopy.