A G Johnson

Effect of meal temperature on gastric emptying of liquids in man.

Serial studies were carried out on six healthy volunteers (19-24 years) to investigate the effect of meal temperature [either 4 degrees C (cold), 37 degrees C (control) or 50 degrees C (warm)] on the rate of gastric emptying of a radiolabelled isosmotic drink of orange juice. The mean maximum intragastric temperature occurred 60 seconds after the onset of ingestion of the warm drink and reached 43.0 degrees C (0.4) mean (SD) while the mean minimum intragastric temperature occurred 45 seconds after the onset of ingestion of the cold drink and reached 21.2 degrees C (1.9). Intragastric temperature then returned to body temperature within 20-30 minutes of ingestion of the warm and cold drinks. Warm and cold drinks appeared to empty from the stomach more slowly than the control drink. The initial rate of gastric emptying of the cold drink was significantly slower than the control drink (p less than 0.05) and the difference in emptying rates between cold and control drinks were significantly correlated with the differences in intragastric temperatures (p less than 0.01). The difference in the initial emptying rates between warm and control drinks were not statistically significant.

Applied Potential Tomography: A New Noninvasive Technique for Measuring Gastric Emptying

Applied potential tomography is a new, noninvasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semisolid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Altering the lateral position of the rod in the tank did not alter the values obtained. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using applied potential tomography were very similar to those obtained using scintigraphy or dye dilution techniques, provided that acid secretion was inhibited by cimetidine. Profiles of emptying of a mashed potato meal using applied potential tomography were also very similar to those obtained by scintigraphy. Measurements of the emptying of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, applied potential tomography is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use, and ideally suited for multiple studies in patients, even those who are pregnant.

Effectiveness of an upper-gastrointestinal haemorrhage unit: a prospective analysis of 900 consecutive cases using the Rockall score as a method of risk standardisation

Objectives To assess the effectiveness of a centralised upper-gastrointestinal haemorrhage (UGIH) unit. Methods The UK Audit of acute UGIH resulted in the formulation of a simple numerical scoring system. The Rockall score categorises patients by risk factors for death and allows case-mix comparisons. A total of 900 consecutive patients admitted to a UGIH unit between October 1995 and July 1998 were analysed prospectively. Patients were given an initial Rockall score and, if endoscopy was performed, a complete score. This method of risk stratification allowed the proportion of deaths (in our study) to be compared with the National Audit using risk standardised mortality ratios. Results The distribution of both initial and final Rockall scores was significantly higher in our study than in the National Audit. A total of 73 (8.1%) patients died, compared with the National Audit mortality of 14%. Risk-standardised mortality ratios using both initial and complete Rockall scores were significantly lower in our study when compared with those in the National Audit. Conclusion A specialised UGIH unit is associated with a lower proportion of deaths from UGIH, despite comprising a greater number of high-risk patients than the National Audit. This lower mortality therefore cannot be attributed to a more favourable case mix and demonstrates that further improvements in mortality for UGIH can be made.

A requiem for the cholecystokinin provocation test

Background—The cholecystokinin provocation test (CCKPT) has been claimed to predict a better symptomatic result after cholecystectomy in patients with acalculous biliary pain. Aims—To examine the predictive value of the CCKPT for symptom relief after cholecystectomy in both CCKPT positive and negative patients. Patients and methods—Fifty eight patients with acalculous biliary pain underwent CCKPT with serial ultrasound gall bladder volumetry. CCKPT positive patients were offered cholecystectomy; negative patients were reassessed and were offered a cholecystectomy if symptoms persisted. Six months after cholecystectomy, the CCKPT was repeated. Results—Of 32 CCKPT positive patients, 27 underwent cholecystectomy and of these, 18 (67%) became symptom-free. Postoperatively, 20 of 25 patients converted to CCKPT negative but five remained CCKPT positive and were symptomatic. Of the 26 CCKPT negative patients, nine became symptom-free without cholecystectomy; six of 14 (42.8%) patients undergoing cholecystectomy became asymptomatic and remained CCKPT negative. Cholecystectomy seemed to reduce symptoms in both groups, but there was no significant difference in the symptomatic outcome between preoperative CCKPT positive and negative patients. Conclusions—In this study, cholecystokinin provocation testing did not predict symptomatic benefit from cholecystectomy and we suggest it should no longer be used in the evaluation of patients with acalculous biliary pain.

Laparoscopic cholecystectomy: a good buy? A cost comparison with small-incision (mini) cholecystectomy.

OBJECTIVES To compare inpatient costs for laparoscopic and small-incision cholecystectomy. DESIGN Retrospective analysis using results of a single blind prospective randomised trial. SETTING Teaching hospital, UK. SUBJECTS 200 patients having elective cholecystectomy. INTERVENTIONS Standard laparoscopic cholecystectomy with conversion to open cholecystectomy if necessary. Small-incision cholecystectomy using high right transverse epigastric incision, enlarged if necessary for safe exposure. MAIN OUTCOME MEASURES Providers inpatient costs. RESULTS Small-incision cholecystectomy cost Pound Sterling 995 and was 29% less expensive than the laparoscopic procedure which cost Pound Sterling 1397. Costs of equipment and operations themselves accounted for most of the difference. Results also suggest that costs to patients and society from time lost away from work may be lower for mini-cholecystectomy. CONCLUSIONS The national health service could be spending over Pound Sterling 10m a year by encouraging laparoscopic rather than small-incision operations for cholecystectomy. Commissioners of health care should question whether the benefits of laparoscopic surgery justify the additional costs.

Applied potential tomography: a new noninvasive technique for assessing gastric function

Applied potential tomography is a new, non-invasive technique that yields sequential images of the resistivity of gastric contents after subjects have ingested a liquid or semi-solid meal. This study validates the technique as a means of measuring gastric emptying. Experiments in vitro showed an excellent correlation between measurements of resistivity and either the square of the radius of a glass rod or the volume of water in a spherical balloon when both were placed in an oval tank containing saline. Altering the lateral position of the rod in the tank did not alter the values obtained. Images of abdominal resistivity were also directly correlated with the volume of air in a gastric balloon. Profiles of gastric emptying of liquid meals obtained using APT were very similar to those obtained using scintigraphy or dye dilution techniques provided that acid secretion was inhibited by cimetidine. Profiles of emptying of a mashed potato meal using APT were also very similar to those obtained by scintigraphy. Measurements of the emptying of a liquid meal from the stomach were reproducible if acid secretion was inhibited by cimetidine. Thus, APT is an accurate and reproducible method of measuring gastric emptying of liquids and particulate food. It is inexpensive, well tolerated, easy to use and ideally suited for multiple studies in patients, even those who are pregnant. A preliminary study is also presented that assesses the technique as a means of measuring gastric acid secretion. Comparison of resistivity changes with measured acid secretion following the injection of pentagastrin shows good correlations. APT might offer a non-invasive alternative to the use of a nasogastric tube and acid collection.

The preoperatively normal bile duct does not dilate after cholecystectomy: results of a five year study

BACKGROUND The common hepatic duct (CHD) is commonly believed to dilate after cholecystectomy but previous studies have either not measured CHD diameter preoperatively or the follow up period is short. AIMS To measure CHD diameter before and after cholecystectomy. METHODS Patients undergoing (open) cholecystectomy and operative cholangiography had ultrasonographic measurement of CHD diameter before, and three and six months, and one and five years after cholecystectomy. The normal duct diameter was considered to be 5 mm or less, with an observer error of ±1 mm. RESULTS Fifty nine patients with normal diameter ducts were studied. The majority (more than 95%) of patients did not have a dilatation of the CHD beyond 6 mm after cholecystectomy. The CHD appeared to increase as well as decrease with an overall trend towards a minor increase at five years. This was not statistically significant if the margin of error of 1 mm was taken into account. CONCLUSION A preoperatively normal CHD does not dilate after cholecystectomy and may require further investigation in symptomatic patients.

Disturbed gastroduodenal motility in patients with active and healed duodenal ulceration

Disordered gastroduodenal motility may promote duodenal ulceration by allowing prolonged acid contact with the duodenal mucosa. Using a multilumen perfused catheter incorporating 3 pH microelectrodes, antral and duodenal pH and antropyloroduodenal pressure activity were recorded in 36 subjects (10 with healed duodenal ulceration, 11 with active duodenal ulceration, and 15 healthy volunteers) during fasting and after a radiolabeled solid test meal. Correct pH probe/catheter position was continuously verified by recording transmucosal potential difference across the pylorus. Patients with active and healed duodenal ulcer had similarly disordered gastroduodenal motility. The chief abnormalities consisted of an increase in postprandial duodenal retroperistalsis (healed duodenal ulceration, 12 +/- 1 events per hour; active duodenal ulceration, 12 +/- 1; control, 6 +/- 1; mean +/- SEM: healed and active duodenal ulceration vs. control, P = 0.004 and P = 0.03, respectively), a reduction in pressure waves sweeping aborally through the duodenum after the meal (healed duodenal ulceration, 22 +/- 4 events per hour; active duodenal ulceration, 23 +/- 3; control, 34 +/- 4: healed and active duodenal ulceration vs. control, P = 0.04 and P less than 0.05, respectively), and an increased incidence of atypical, complex forms of coordinated duodenal motor activity throughout the study (postprandial data; healed duodenal ulceration, 8 +/- 1 events per hour; active duodenal ulceration, 10 +/- 1; control, 4 +/- 1: healed and active duodenal ulceration vs. control, P = 0.02 and P less than 0.02, respectively). In addition, gastric emptying of the solid test meal was significantly delayed in healed, but not active, duodenal ulceration [half-emptying time, healed duodenal ulceration 185 minutes (117-235); active duodenal ulceration 102 minutes (80-200); control 107 minutes (78-130): healed duodenal ulceration vs. control, P less than 0.009]. Duodenal bulb pH was similar in controls and patients with active duodenal ulceration; however, bulb pH was less than 4 for a significantly greater period of time in healed duodenal ulceration compared with active ulcer patients, particularly after the meal. In conclusion, duodenal ulcer disease is associated with disturbed gastroduodenal motility, even when the ulcer is quiescent and when intraduodenal acidity is low. In healed duodenal ulceration, disturbed motility may promote ulcer relapse by impairing acid clearance from the bulb. However, in active ulceration other factors such as mucosal bicarbonate secretion may have a more influential role in determining intraduodenal pH.

Comparison of applied potential tomography and impedance epigastrography as methods of measuring gastric emptying

Two new non-invasive methods of measuring gastric emptying, impedance epigastrography (IE) and applied potential tomography (APT) have been compared. Measurements in vitro showed that there is a good correlation between the square of the radius of a glass rod placed in the centre of a tank and values obtained by IE or APT. However, if the rod is moved anteriorly in the tank IE values increase markedly, whereas APT values are unchanged. Both APT and IE can be used to follow gastric emptying of liquid meals; however, the results obtained using APT are more reproducible and have a better correlation with those obtained simultaneously by scintigraphy. Neither method was able accurately to follow gastric emptying unless gastric acid secretion was inhibited by cimetidine.

Evaluation of applied potential tomography as a new non-invasive gastric secretion test.

Applied potential tomography (APT) is a new, non-invasive technique that can yield sequential images of changes in the resistivity of gastric contents. Studies were performed to investigate the application of APT to measure gastric acid secretion. Experiments in 20 normal volunteers showed that changes in gastric resistivity were closely correlated with changes in the volume (r = 0.80), the acidity (r = 0.83) and the total conductivity of gastric contents (r = 0.87). Studies in 13 patients referred for a pentagastrin test showed that changes in gastric resistivity before pentagastrin were closely correlated with basal acid output measured on a separate occasion (r = 0.85, p less than 0.001), while changes in gastric resistivity after pentagastrin were correlated with maximal acid output (r = 0.58, p less than 0.05). Ingestion of alcohol by six normal subjects decreased gastric resistivity markedly, probably due to alcohol induced gastric acid secretion as it was prevented by cimetidine. Applied potential tomography is a safe non-invasive method of measuring gastric acid secretion. The equipment is simple to use, and the test is comfortable and acceptable to patients.