Inter-observer variability in the reporting of dynamic evacuation proctography.

OBJECTIVE: To determine the degree of inter-observer variability between two reporters of dynamic evacuation proctography (DEP). PATIENTS AND METHODS: The videotapes of 136 patients who had undergone the investigation of DEP in a 1-year period were retrospectively and independently reported by two of the authors. The authors recorded the presence or absence of an anterior rectocoele (as well as size-small, medium or large), an intussusception, a rectal prolapse and any degree of non-relaxing puborectalis syndrome (NRPS). RESULTS: The results were analysed using the κ statistic. I.W.I. reported 18% of the proctograms as normal. S.G.S. reported 26% of the proctograms as normal. κ scores for agreement on the presence or absence of rectal prolapses, NRPS, intussusception and anterior rectocoeles between the two reporters were 0.79, 0.70, 0.54 and 0.82, respectively. CONCLUSION: Usefulness of an investigation is dependent upon its reproducibility and hence on the degree of inter-observer variability in its reporting. Our study shows that DEP is a useful investigation for delineating the mechanics of the pelvic floor and that consistency of reporting in our Department is good.

The effects of 300 mg ranitidine at night, twice daily and four times daily on intragastric acidity in normal subjects.

The aim of this study was to compare to placebo the effects of 300 mg ranitidine nocte, b.d. and q.d. on intragastric acidity. The study was performed on healthy male subjects and intragastric acidity measured by radiotelemetry. All active treatments significantly decreased 24-hr acidity, with a median suppression of 61.0% with 300 mg ranitidine nocte, 77.7% with 300 mg b.d. and 78.0% with 300 mg q.d.s. There was no significant difference between the effects of two higher dose regimens; although the 300 mg q.d.s. suppressed daytime acidity more than 300 mg b.d. (88.9% vs. 77.8%), it suppressed nocturnal acidity less effectively (65.5%) than either 300 mg nocte (92.9%) or 300 mg b.d. (90.0%). These data suggest that only modest additional therapeutic acid inhibition can be achieved by increasing the dose of ranitidine above 600 mg daily.

Effect of anorectal eversion during restorative proctocolectomy on anal sphincter function.

Twenty-six patients underwent restorative proctocolectomy with end-to-end ileal pouch-anal anastomosis, without resection of the anal mucosa, by the eversion technique. Before surgery patients underwent tests of anorectal function. These were repeated a median of 8 (range 3-21) months after operation. The median (range) maximum resting anal pressure was 93 (36-149) cmH2O before and 71 (40-131) cmH2O after operation (P = 0.002). The median (range) maximum squeeze pressure before operation was 136 (73-280) cmH2O; it was 149 (69-290) cmH2O afterwards (P not significant). The median (range) length of the anal sphincter was 3.5 (2.5-4.5) cm before and 3.5 (2.0-4.5) cm after operation (P not significant). Thresholds for sensation in the upper, middle and lower thirds of the anal canal before and after operation were, respectively, 8.7 versus 8.7, 6.8 versus 7.4 and 4.2 versus 6.2 mA (P not significant). All 26 patients were continent, although one experienced minor leakage. Function of the anal sphincter is not significantly impaired by eversion of the rectum and anus during restorative proctocolectomy.

Is antral gastrin important in the resistance of duodenal ulcers to H2 receptor antagonists or in recurrent ulceration after highly selective vagotomy?

Basal serum gastrin, integrated gastrin response to a meal, and integrated gastrin response to insulin induced hypoglycaemia were measured in 60 patients with duodenal ulcer before and after elective highly selective vagotomy to determine whether antral gastrin has a role in resistance to H2 receptor antagonist treatment which the patients had received before surgery or in the development of recurrent ulceration after vagotomy. The basal gastrin, integrated gastrin response to a meal, and the integrated gastrin response to insulin were similar in patients whose ulcers healed after H2 receptor agonist treatment or were refractory to at least three months of this treatment. The same parameters measured before or after highly selective vagotomy were similar in patients who eventually developed recurrent ulceration compared with those who did not. As expected the basal and meal stimulated (but not insulin stimulated) serum gastrin values increased after highly selective vagotomy. Ulcer patients with particularly high gastrin values (whether basal or stimulated) were not more resistant to H2 receptor antagonist treatment or prone to develop ulcer recurrence after highly selective vagotomy. This study suggests that antral gastrin is not important in 'resistance' of duodenal ulceration either to H2 receptor antagonist treatment or to highly selective vagotomy.

The effects of 15 days of dosing with placebo, sufotidine 600 mg nocte or sufotidine 600 mg twice daily upon 24-hour intragastric acidity and 24-hour plasma gastrin.

The acid inhibitory effect of sufotidine, a potent, long-lasting, competitive H2-receptor antagonist, was studied in 12 healthy males in a double-blind, randomized, three-way cross-over study of the effect of placebo, sufotidine 600 mg nocte and sufotidine 600 mg b.d. given over 15 days. On day 1 and 15 of dosing with each regimen, each subject's 24-h ambulatory intragastric acidity was measured by radiotelemetry and 24-h plasma gastrin profiles were derived from hourly venous blood samples. Acid suppression was calculated as the decrease in the area under the curve of hydrogen ion activity vs time from that observed on placebo, and 24-h plasma gastrin calculated as the area under the curve of plasma gastrin concentration vs time. Twenty-four hour intragastric acidity during the fifteenth day of dosing with sufotidine 600 mg nocte and sufotidine 600 mg b.d. did not differ significantly, but on the first and fifteenth day of dosing nocturnal acidity was decreased to a greater extent by sufotidine 600 mg nocte than sufotidine 600 mg b.d. (P less than 0.005). After 15 days, the acid suppression afforded by sufotidine 600 mg b.d. was significantly attenuated (P less than 0.0005); this was associated with a rise in 24-h plasma gastrin (P less than 0.001). Thus, tolerance to the acid inhibitory effect of H2-receptor antagonists exists and is of rapid onset. We suggest that tolerance is mediated by the temporally associated rise in 24-h plasma gastrin, but we cannot exclude the possibility that other mechanisms, such as up-regulation of H2-receptors, also play a part.

A prospective comparison of the effects of placebo, ranitidine and highly selective vagotomy on 24 h ambulatory intragastric pH in patients with duodenal ulcer.

Twenty-four hour ambulatory intragastric pH (24 h IGpH) recording, a highly reproducible technique, was used to compare the effects of ranitidine and highly selective vagotomy (HSV) in 20 patients who had been referred for surgical treatment of duodenal ulcer. The 24 h IGpH was recorded when they were taking either placebo or ranitidine 300 mg at 10 pm, and again 4 to 13 weeks after elective HSV. Median 24 h IGpH and 24 h hydrogen ion activity (24 h [H+]) were calculated for each patient. Median (quartile) 24 h IGpH was 1.4 (1.3-1.6) with placebo, 2.2 (1.8-2.7) after ranitidine and 2.6 (1.8-3.7) after HSV. IGpH was significantly higher after both ranitidine (P less than 0.0001) and HSV (P less than 0.0001) than after placebo, but IGpH after ranitidine did not differ from IGpH after HSV (0.5 greater than P greater than 0.4). HSV reduced 24 h [H+] by a median 68 per cent (quartiles, 47-82 per cent) whereas ranitidine reduced it by only 50 per cent (34-69 per cent, 0.1 greater than P greater than 0.05). The 24 h pH recording was then analysed as two distinct periods; 'daytime' (8 am to midnight) and 'night-time' (midnight to 8 am). HSV reduced daytime [H+] by a median 77 per cent (59-93 per cent) whereas ranitidine reduced it by only 30 per cent (13-45 per cent, P less than 0.0001). HSV reduced night-time [H+] by a median 57 per cent (40-83 per cent) but ranitidine reduced it by a median 92 per cent (78-98 per cent, P less than 0.01). Thus, HSV inhibits gastric acidity more during the day than at night, whereas ranitidine given at 10 pm effectively suppresses night-time acidity but is much less effective in suppressing daytime acidity. However both HSV and ranitidine will heal more than 90 per cent of duodenal ulcers. Hence, contrary to Dragstedt's teaching, suppression of nocturnal acidity is not of crucial importance for the healing of duodenal ulcers.

Pressure and prolapse--the cause of solitary rectal ulceration.

The cause of solitary rectal ulceration has been investigated using a method that radiologically visualises rectal voiding whilst simultaneously measuring intrarectal pressure and external anal sphincter electromyographic activity. Control subjects and patients with the solitary rectal ulcer syndrome, both with and without mucosal ulceration, have been studied. A high incidence of rectal prolapse (94%) was present in the patients who voided. Overactivity of the anal sphincter during evacuation contributed to the fact that patients with mucosal ulceration required higher intrarectal pressures to void than the controls and the patients without mucosal ulceration. The results indicate that a combination of rectal prolapse and a high voiding pressure may act to cause the mucosal ulceration in this syndrome by exposing the rectal wall to a high transmural pressure gradient.

New method for the dynamic assessment of anorectal function in constipation.

A new dynamic technique for the investigation of anorectal function has been developed. This involves radiological visualization of the rectum during voiding of a semisolid radio-opaque contrast medium, and simultaneous measurement of the intrarectal pressure and electrical activity of the external anal sphincter. The method has been used to study patients (n = 16) with profound difficulty passing formed stool. It has demonstrated an abnormal increase in the activity of the puborectalis and superficial and sphincter muscles during voiding in these patients, compared with normal subjects (n = 6). The inability to void was associated with failure to widen the anorectal angle on straining.

Calculation of short-term changes in body fat from measurement of respiratory gas exchange.

A method is presented where the gain in body fat of patients receiving intravenous nutrition (IVN) may be computed using indirect calorimetry. When patients are administered their nutritional requirements soley in the form of glucose and amino acids, metabolism of these will result in changes in the exchange of carbon dioxide and oxygen. Since net fat synthesis results in the production of excess carbon dioxide whereas degradation results in a net reduction in the production of carbon dioxide, changes in RQ will reflect underlying changes in net fat balance. A correction may be applied to these measurements to allow for net protein balance. The basic equations and stoichiometry for the synthesis of tripalmitin from glucose are shown together with the derivation of the formulae that enable the calculation of fat changes to be made. A group of 13 patients was used to assess the technique and given energy at 1.5 times resting metabolic expenditure together with adequate nitrogen as amino acids to maintain protein balance. The patients were monitored daily in the resting state and fed at a constant rate so that errors due to discontinuous intake or exercise were avoided. The group was found to gain 874 +/- 243 g fat during the 14 day study. Although individual changes of fat in patients ranged from -169 to +2487 g, net synthesis of fat was found in ten of them. It is suggested that indirect calorimetry is useful not only in the assessment of actual expenditure in patients but can also be used to quantify the fate of administered fuels during intravenous nutrition.