Biomedical subjects

C B Dalton

Publications and source records attributed to C B Dalton.

At least 37 records · Page 2Linked to original sources

PubMed1992

Effects of nifedipine on esophageal tone and perception of esophageal distension.

The effects of nifedipine (20 mg orally) on esophageal body resting tone and perception of esophageal distension were compared with those of placebo in 10 healthy volunteers, using a double-blind crossover design. A 3-cm silicon balloon positioned 10 cm above the lower esophageal sphincter was inflated with 2-20 ml of air, in 2-ml increments. The subjects scored their chest sensations, while pressure in the balloon was continuously recorded. In each experiment three series of measurements were made, at baseline and 15 and 30 min after administration of nifedipine or placebo. Bench tests were run to determine pressure-to-volume relationships for each of the balloons used in the study. Thirty minutes after nifedipine ingestion, a significant decrease in systolic blood pressure (from 112.6 +/- 2.3 to 99.0 +/- 2.0 mm Hg) was observed. Amplitude and duration of esophageal peristaltic contractions were significantly decreased by nifedipine (from 128.1 +/- 16.7 to 98.7 +/- 10.6 mm Hg and from 3.9 +/- 0.3 to 3.3 +/- 0.2 sec, respectively). With balloon volumes of 8 ml and higher, balloon pressures were higher with the balloon in the esophagus than on the bench, the difference being determined by the compliance of the esophagus. This difference rose from 18.5 +/- 6.8 to 40.2 +/- 7.2 mm Hg (8-20 ml) with placebo and from 23.1 +/- 3.7 to 35.9 +/- 5.8 mm Hg with nifedipine. No significant differences between nifedipine and placebo were found. The esophageal sensation scores increased linearly with increasing balloon volume from 6 ml onwards. Nifedipine had no significant effect on the perception of esophageal balloon distension.

Adult↗

PubMed1992

Cerebral potentials evoked by oesophageal distension in patients with non-cardiac chest pain.

Cerebral evoked potential recording was used to study the oesophagus-brain axis in 10 controls and 10 patients with non-cardiac chest pain with a manometric diagnosis of either nutcracker oesophagus or diffuse spasm and a positive edrophonium test. A series of 50 inflations (10/minute; inflation rate of 170 ml/second) of an intraoesophageal balloon (5 cm proximal to the lower oesophageal sphincter) was performed in each subject. Three different inflation volumes were used and were individually determined to cause no sensation, slight sensation, and definite sensation, respectively (volume ranges: 2-8 ml, 5-18 ml, and 8-22 ml). All signals were coded and their quality was scored on a scale from 0 (no recognisable pattern) to 5 (well defined potential of good quality) by four 'blinded' observers. The evoked potential quality scores and amplitude of the major peaks increased significantly (p less than 0.01) with increasing sensation, both in patients and in controls. In the patients, quality score and amplitude of all four peaks of the evoked potentials were lower (p less than 0.05) and latencies of two of the four peaks were longer (p less than 0.02) than in the controls. The volumes of air required to produce the various sensations were lower in the patients (p less than 0.01). When divided by the balloon volume, amplitude and quality of the evoked potential were no longer significantly different between the groups. These results suggest that the increased perception of oesophageal distension in patients with non-cardiac chest pain is caused by altered central processing rather than (functionally) abnormal receptors in the oesophageal wall.

Adult↗

PubMed1992

Musculoskeletal chest wall syndromes in patients with noncardiac chest pain: a study of 100 patients.

One hundred patients with chest pain and negative coronary arteriography were evaluated for musculoskeletal chest wall findings. Sixty-nine patients had chest wall tenderness. Typical chest pain was evoked by palpation in 16 patients. Tender areas were not found in a control group of patients without chest pain. A diagnosis of fibrositis could be made in five patients, including two in whom chest palpation reproduced typical chest pain. The sternal and xiphoid area, left costosternal junctions, and left anterior chest wall were the areas where tenderness was most common, but no significant differences were found comparing locations of tenderness in those with reproduction of typical pain. There was no significant difference in location, exacerbating factors, or other musculoskeletal symptoms among different groups of patients. Thus, most patients with noncardiac chest pain have chest wall tenderness that is not found in a control group without chest pain. However, reproduction of pain by palpation, a more specific diagnostic finding, is found in a minority of these patients.

Adult↗

PubMed1991

Acid perfusion test and 24-hour esophageal pH monitoring with symptom index. Comparison of tests for esophageal acid sensitivity.

The acid perfusion (Bernstein) test and esophageal pH monitoring are the two most popular tests for identifying esophageal acid sensitivity in difficult cases of reflux disease. Therefore, we prospectively compared these test results in 75 consecutive noncardiac chest pain patients who had both an acid perfusion test and chest pain during 24-hr pH testing. A positive acid perfusion test was defined by the replication of the patient's typical chest pain twice by the acid infusion. Esophageal pH testing identified abnormal amounts of acid reflux and correlated symptoms with acid reflux--the "symptom index." Fifteen patients (20%) had a positive acid perfusion test while 45 patients (59%) had a positive symptom index (range 6-100%). Only 9/34 (26%) patients with abnormal reflux had a positive acid perfusion test. Although it had excellent specificity (83-94%), the acid perfusion test had poor sensitivity (32-46%) when compared to the symptom index regardless of the percent positive cutoff level. The best positive predictive value for the acid perfusion test was 87%, but this occurred when the test sensitivity was 32%. Modifying the end point of a positive acid perfusion test to include heartburn improves the sensitivity (52-67%) while markedly compromising specificity and positive predictive value. Thus, esophageal pH monitoring correlating symptoms with acid reflux is superior to the acid perfusion test for identifying an acid sensitive esophagus in patients with noncardiac chest pain.

Chest Pain↗

PubMed1991

Diffuse esophageal spasm. A rare motility disorder not characterized by high-amplitude contractions.

Diffuse esophageal spasm (DES) has frequently been described as a motility disorder characterized by simultaneous, high-amplitude contractions. We reviewed the results of esophageal manometry testing on a total of 1480 patients referred to our lab over 36 months. Lower esophageal sphincter (LES) pressure was determined by a mean of four station pull-through. Esophageal body motility was assessed following 10 wet swallows. In our lab a diagnosis of DES is made when greater than 10% but less than 100% of contractions are simultaneous. Manometric findings of DES were rare, with an overall prevalence of 4% (56/1480). Of the 56 patients with a manometric diagnosis of DES, high-amplitude (mean greater than or equal to 180 mm Hg) peristaltic contractions were found in only two (4%). No simultaneous contractions with amplitude greater than or equal to 180 mm Hg were seen. Pressures of simultaneous contractions were consistently lower than peristaltic contractions. A hypertensive LES pressure (greater than or equal to 45 mm Hg) was present in 5/56 DES patients (9%). Poor LES relaxation was found in 7/56 DES patients (13%). We conclude that DES is a rare manometric finding, regardless of the reason for referral, and that the occurrence of high-amplitude contractions in DES is equally rare.

Esophageal Spasm, Diffuse↗

PubMed1991

Effect of intraperitoneal fluid volume changes on esophageal pressures: studies in patients on continuous ambulatory peritoneal dialysis.

Esophageal manometric studies were performed in 11 patients on continuous ambulatory peritoneal dialysis (CAPD) with the dialysis fluid in the peritoneal cavity, after emptying and again after reinfusion. No systematic changes were found in intragastric or lower esophageal sphincter (LES) pressures at any time. No differences in mean distal esophageal amplitude (DEA), duration, or velocity of peristalsis were noted. Although upper gastrointestinal problems are common in CAPD patients and were reported by eight of 11 patients, this study suggests that these symptoms cannot be explained by changes in gastric and esophageal pressures.

Adult↗

PubMed1991

Twenty-four-hour esophageal pH monitoring: the most useful test for evaluating noncardiac chest pain.

STUDY OBJECTIVE: To compare the diagnostic capabilities of traditional esophageal tests (manometry and provocative testing with acid and edrophonium) and 24-hour esophageal pH monitoring in identifying an esophageal cause of chest pain. DESIGN: A prospective study of 100 consecutive patients referred by cardiologists to the esophageal laboratory for evaluation of esophageal causes of chest pain. SETTING: Tertiary-referral university hospital. METHODS: Esophageal manometry performed with 10 wet swallows of water. Acid perfusion (0.1 N hydrochloric acid) and edrophonium (80 micrograms/kg intravenously) tests were placebo-controlled with a positive study defined as replication of typical chest pain. Esophageal pH monitoring identified (1) abnormal acid exposure times in the upright, supine, or combined position, and (2) correlation between symptoms and acid reflux, i.e., symptom index. The esophagus was identified as "probably" contributing to chest pain only if the acid or edrophonium test was positive or if there was a positive correlation between symptoms and acid reflux during pH monitoring. RESULTS: Esophageal manometry was abnormal in 32 patients (32%), but patients were asymptomatic during the study. The acid perfusion test was positive in 18 of 95 patients (19%), and the edrophonium test was positive in 15 of 78 patients (19%). Abnormal acid exposure times were found in 48 patients (48%). Of the 83 patients with spontaneous chest pain during 24-hour pH testing, 37 patients (46%) had abnormal reflux parameters and 50 patients (60%) had a positive symptom index (mean positive score 56%, range 6% to 100%). CONCLUSIONS: Acid reflux is a common and potentially treatable cause of noncardiac chest pain. Traditional esophageal tests usually miss this diagnosis. Twenty-four-hour esophageal pH monitoring with symptom correlation is the single best test for evaluating patients with noncardiac chest pain.

Adult↗

PubMed1990

Comparison of esophageal manometry, provocative testing, and ambulatory monitoring in patients with unexplained chest pain.

Prolonged ambulatory esophageal pH and pressure monitors are being developed to evaluate noncardiac chest pain. This new technology needs comparison with conventional esophageal tests before determining which studies are most useful in diagnosing and treating esophageal chest pain. Therefore, we studied 45 patients with esophageal manometry, acid perfusion and edrophonium tests, and 24 hr pH and pressure monitoring. Manometry was abnormal in 20 patients (44%) with nutcracker esophagus, the most common motility disorder. Fifteen (33%) had positive acid perfusion test and 24 (55%) positive edrophonium test. During ambulatory monitoring, all patients experienced chest pain with a total of 202 individual events: 32 events (15%) secondary to acid reflux, 15 (7%) secondary to motility abnormalities, 7 (3%) to both pH and pressure changes, and 149 events (74%) occurred in the absence of any abnormal pH or motility changes. Patients with normal manometry were significantly (P less than 0.01) more likely to have acid reflux chest pain events than did nutcracker patients, who had an equal frequency of pH and motility events. A positive acid perfusion test was significantly associated with abnormal pressure events (P = 0.02; odds ratio 5.95), while a positive edrophonium test more likely predicted acid reflux chest pain during 24-hr monitoring (P = 0.007; odds ratio 7.25). Therefore, abnormal manometry and positive provocative tests point to the esophagus as the likely source of chest pain. However, ambulatory pH and pressure monitoring are required to accurately define the relationship between chest pain and acid reflux or motility disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Chest Pain↗

PubMed1990

Pharyngeal/upper esophageal sphincter pressure dynamics in humans. Effects of pharmacologic agents and thermal stimulation.

Extensive physiological studies of swallowing have been carried out in laboratory animals; however, similar studies in humans have been limited by available technology. In this study we describe the use of a solid-state circumferential sphincter transducer to define manometric characteristics of the human pharynx and upper esophageal sphincter (UES). Effects of pharmacologic agents and thermal stimulation are also described. We studied nine normal volunteers on three separate days. All studies were done in the upright position and consisted of a station pull-through of the UES and six wet swallows with the sphincter transducer in the most proximal segment of the UES and a posteriorly oriented single transducer 5 cm proximal in the pharynx. Baseline studies preceded all drug studies. Effects of bethanechol were studied on day 1, cold stimulation and benzonatate on day 2, edrophonium and atropine on day 3. The UES resting pressure showed large intrasubject day-to-day variations; however, mean values did not differ. There were no effects on UES relaxation or swallow coordination with any of the pharmacologic agents, although benzonatate produced multiple pharyngeal contractions.

Adult↗

PubMed1990

Edrophonium provocative test in noncardiac chest pain. Evaluation of testing techniques.

Edrophonium chloride is used frequently as a provocative agent in the assessment of noncardiac chest pain (NCCP). However, the optimum dose and most appropriate method of interpreting test results is controversial. We studied 150 consecutive NCCP patients and 50 age-matched controls who alternately received either 80 micrograms/kg or 10 mg intravenous bolus doses of edrophonium preceded by saline placebo injections. Distal esophageal pressures were measured before and after drug injection in response to ten 5-cc wet swallows. Following 10 mg of edrophonium, 33% of patients and 4% of controls reported chest pain, while 29% of patients and no controls receiving the 80 micrograms/kg dose complained of chest pain. Amplitude changes after either dose were not significantly different for all comparisons, but the duration of response did distinguish the two doses in patients with chest pain. A significantly greater (P = 0.01) increase in distal contraction duration occurred after 10 mg (74 +/- 12%; +/- SE) compared to 80 micrograms/kg dose (43 +/- 6%). However, individual responses to the two doses overlapped considerably. If a positive test is redefined to include both chest pain and manometric changes that are significantly different from controls, the positivity rate changes drastically; 33% to 9% in the 10-mg group and 30% to 3% in the 80-micrograms/kg group. Side effects were similar between doses, but there was a significant (P = 0.02) linear relationship between intensity of side effects and the edrophonium dose per kilogram of body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗

PubMed1990

Effects of body position and bolus consistency on the manometric parameters and coordination of the upper esophageal sphincter and pharynx.

The development of a solid-state intraluminal sphincter transducer has alleviated many of the problems associated with manometric studies of the upper esophageal sphincter (UES) and pharynx (P). We used this technology to study the effect of position (upright vs. supine) on resting UES pressures and the pressure dynamics of the UES/P complex during both wet and dry swallows in 11 normal volunteers and the effects of foods of different consistencies on the UES/P swallow dynamics in 10 normal volunteers. The UES/P coordination parameters were defined as the 15 time intervals that can be measured between any 2 of 6 pertinent points: the beginning, peak, and end of the pharyngeal contraction and the beginning, nadir, and end of the UES relaxation. Data from both the circumferential transducer used to measure sphincter pressures and a standard microtransducer used to measure pharyngeal pressures were collected on-line by an Apple IIe microcomputer and analyzed by programs written in our laboratory. Significant changes in swallow coordination were measured between upright and supine swallows of the same bolus size, between wet and dry swallows in the same position, and among foods of varying consistencies. Resting UES pressure was unchanged by position and pharyngeal contraction pressure was unchanged by bolus size or consistency.

Adult↗

PubMed1990

Pharyngeal and upper esophageal sphincter manometry in humans.

Manometric studies of pharyngeal-upper esophageal sphincter (UES) coordination during swallowing have proven difficult. Asymmetry of the UES makes pressure measurements with a single, unoriented transducer suspect. Perfused systems lack the necessary response rate for measuring peak pharyngeal contraction pressures. Precise quantification of the coordination of pharyngeal contractions and UES relaxations during swallowing is difficult because of rapid pressure changes. We tested a modified solid-state transducer that measures pressures over 360 degrees. This transducer was placed in the proximal UES with a second, single transducer 5 cm proximal. Data were collected and analyzed with an Apple IIe microcomputer. A computer program was developed to measure nine timing sequences, UES resting pressure, nadir of UES relaxation, and pharyngeal contraction pressures. We studied 21 volunteers with six swallows each for dry, 5, 10, and 20 ml of water. Dry swallows differed significantly (P less than 0.05) from wet (5 ml). All timing sequences became progressively longer with increasing bolus size. Residual pressures were unchanged. Timing sequences were also measured for wet (5 ml) and dry swallows in seven volunteers using a Dent sleeve and single perfused orifice in the UES; no differences were seen.

Adult↗

PubMed1990

The prevalence of abnormal esophageal test results in patients with cardiovascular disease and unexplained chest pain.

The purpose of our study was to assess the prevalence of esophageal test abnormalities in patients with known cardiovascular disease and persistent chest pain. We performed a retrospective review of symptoms, manometry, and provocative test results performed on patients with undiagnosed chest pain. The 220 patients with angiographically determined cardiac disease and persistent chest pain were divided into three groups: coronary artery disease (125 patients), mitral valve prolapse (38 patients), and coronary bypass/angioplasty (57 patients). A comparison group consisted of 159 patients with noncardiac chest pain. All patients underwent esophageal manometry and placebo-controlled provocative testing (acid perfusion test and edrophonium chloride test). The prevalence of esophageal motility disorders in the noncardiac chest pain group (27%) was similar to that in the coronary artery disease (24%), mitral valve prolapse (37%), and coronary bypass/angioplasty (30%) groups. The frequency of nutcracker esophagus (11% to 16%) and diffuse esophageal spasm (2% to 7%) was remarkably constant. The prevalence of any positive provocative result in the noncardiac chest pain group (27%) was similar to that in the coronary artery disease (19%), mitral valve prolapse (32%), and coronary bypass/angioplasty (20%) groups. Furthermore, completely negative results of esophageal investigation occurred in 55%, 62%, 42%, and 59% of the respective patient groups.

Acids↗

PubMed1990

Aging-related alterations in human upper esophageal sphincter function.

Recent improvements in manometric catheters have made measurement of pharyngeal (P) and upper esophageal sphincter (UES) swallowing mechanics more reliable. Few studies have attempted to evaluate the effect of normal aging on P and UES mechanics. Pharyngeal and upper esophageal sphincter dynamics were studied in 10 healthy elderly adults (age greater than 60; range 62-79 yr) and 10 younger adults (age less than 60; range 24-59 yr). A solid-state intraluminal transducer system was used with a proximal unidirectional Konigsberg microtransducer and a circumferential (sphincter) transducer located 5 cm distally. Mean resting UES pressure was significantly (p less than 0.05) lower in the elderly than in the younger subjects (52 +/- 5 vs 72 +/- 6 (SE)) mm Hg. A significant inverse relation (R = -0.54; p less than 0.02) was found between age and resting UES pressure. Time from peak of pharyngeal contraction to UES nadir was significantly (p less than 0.05) shortened in the healthy elderly vs younger controls (10 +/- 30 vs 90 +/- 20 ms) during dry swallows. Our studies indicate that aging is associated with lower resting UES pressure and delayed UES relaxation, relative to the pharyngeal peak.

Adult↗

PubMed1990

Manometry and radiology. Complementary studies in the assessment of esophageal motility disorders.

The relationship between radiological and manometric findings in esophageal motility disorders is poorly understood. Therefore, 20 subjects (4 normal; 13 diffuse spasm; 3 other motility disorders) were studied using synchronous manometry and videofluoroscopy with alternate 5-ml and 10-ml barium swallows. A total of 181 swallows were analyzed. Concordance between manometry and fluoroscopy was excellent for individual swallows (98%), groups of 5 swallows (97%), and final diagnoses (90%). Contraction onset intervals less than 0.8 s apart over 5 cm (velocity greater than 6.25 cm/s) were critical in determining abnormal bolus transit (98% sensitivity and positive predictive value). Radiologically, segmental tertiary activity (complete luminal obliteration) was always associated with disrupted primary peristalsis, but nonsegmental tertiary activity was often seen with normal bolus transit and did not have a specific manometric correlate. Four patterns of interrupted peristalsis radiologically were found--segmental tertiary contractions, a generalized esophageal contraction, absence of motor activity, or discoordinated "to-and-fro" movement. Surprisingly, nearly complete barium clearance occurred by the first two mechanisms in two thirds of swallows. Thus, the authors believe radiology and manometry are both excellent studies for identifying abnormal esophageal peristalsis. In difficult cases, these tests give complementary information because radiology assesses bolus movement while manometry provides quantitative pressure data.

Barium Sulfate↗

PubMed1989

Stress induces alteration of esophageal pressures in healthy volunteers and non-cardiac chest pain patients.

The present study was designed to explore the relationship between psychological stress and esophageal motility disorders. Nineteen non-cardiac chest pain patients (10 with the nutcracker esophagus and nine with normal baseline manometry) and 20 healthy control subjects were administered two acute stressors: intermittent bursts of white noise and difficult cognitive problems. The results indicated that the esophageal contraction amplitudes and levels of anxiety-related behaviors of non-cardiac chest pain patients and control subjects were significantly greater during the stressors than during baseline periods. All patients demonstrated significantly greater (P less than 0.01) increases in contraction amplitude and anxiety-related behavior during cognitive problems than during the noise stressor. The nutcracker esophagus patients showed a greater increase in contraction amplitude during the problems (23.50 +/- 9.42 mm Hg, X +/- SE) than control subjects (P less than 0.01), while the amplitude changes of chest pain patients with normal baseline manometry were not significantly greater than that of control subjects (9.00 +/- 1.91 mm Hg). The present results identified an increase in contraction amplitude as the primary esophageal response to stress. The possible interaction of esophageal contraction abnormalities, psychological stress, and the perception of chest pain is discussed.

Adult↗

PubMed1989

Hypertensive lower esophageal sphincter: what does it mean?

The hypertensive lower esophageal sphincter (LES) (mean LES pressure greater than 45 mm Hg; LES relaxation greater than 75%; normal peristalsis) is a poorly characterized motility disorder associated with chest pain and dysphagia. Therefore, we carried out a multidisciplinary study to assess esophageal pressures and function in 15 symptomatic hypertensive LES patients (3 men, 12 women; mean age, 53 years). On-line computer analysis showed a significant (p less than 0.05) increase in LES pressure (55.5 versus 14.9 mm Hg) and residual pressure (6.8 versus 1.1 mm Hg) as well as a decrease in percentage of LES relaxation (87 versus 93%) in patients compared with age-matched controls. All patients had normal peristalsis but 7 of 15 had nutcracker esophagus (mean distal amplitude, 216 mm Hg). No patient had evidence of impaired liquid transport on barium esophagram. The emptying of solids as assessed by radionuclide scans was normal in 14 of 15 patients. Of the 12 patients who completed both psychological inventories, nine had elevated scores on scales assessing anxiety and somatization. The heterogenous nature of this disorder is illustrated by a patient with a changeable narrowing in the distal esophagus associated with the transient impaction of a marshmallow. Dysphagia but not chest pain improved after pneumatic dilatation. We conclude that the hypertensive LES is a heterogenous disorder. Despite abnormal LES parameters, most patients have normal esophageal function, and frequent psychological abnormalities may contribute to their report of symptoms. A minority have abnormal esophageal transit.

Adult↗

PubMed1989

Acid perfusion test: does it have a role in the assessment of non cardiac chest pain?

Using 24 hour pH monitoring as a reference standard, the usefulness of the acid perfusion (AP) test in predicting gastro-oesophageal reflux disease (GORD) was assessed in 71 non-cardiac chest pain (NCCP) patients and 23 endoscopic oesophagitis patients. Of the 71 NCCP patients, 35 had a positive AP test (of whom 20 had an abnormal 24 hour pH) and 36 had a negative AP test (of whom 14 had an abnormal 24 hour pH study). Thus, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the AP test in this group was 59%, 59%, 57%, and 61%, respectively. The corresponding values in the oesophagitis group were 85%, 67%, 94%, and 40%. In the NCCP group when heartburn alone was used as the positive criterion the PPV rose to 74%. When chest pain with or without heartburn was used, however, the PPV dropped to 38%. A 'symptom index' was used to define the number of chest pain episodes that were caused by acid reflux. Only 48% of AP test positive patients had demonstrable acid mediated chest pain. In the NCCP population with a normal oesophageal examination (1) AP test reproduction of chest pain is poorly predictive of GORD; (2) AP test reproduction of heartburn is more predictive of GORD but does not ensure that the chest pain is caused by GORD; (3) a negative AP test does not exclude GORD and (4) only 48% of AP test positive patients have demonstrable acid mediated chest pain. The ambulatory 24 hour pH test may have rendered the AP test obsolete in the assessment of GORD as the cause of NCCP.

Adult↗