A procedure-specific systematic review and consensus recommendations for postoperative analgesia following laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy has advantages over the open procedure for postoperative pain. However, a systematic review of postoperative pain management in this procedure has not been conducted.

METHODS

A systematic review was conducted according to the guidelines of the Cochrane Collaboration. Randomized studies examining the effect of medical or surgical interventions on linear pain scores in patients undergoing laparoscopic cholecystectomy were included. Qualitative and quantitative analyses were performed. Recommendations for patient care were derived from review of these data, evidence from other relevant procedures, and clinical practice observations collated by the Delphi method among the authors.

RESULTS

Sixty-nine randomized trials were included and 77 reports were excluded. Recommendations are provided for preoperative analgesia, anesthetic and operative techniques, and intraoperative and postoperative analgesia.

CONCLUSIONS

A step-up approach to the management of postoperative pain following laparoscopic cholecystectomy is recommended. This approach has been designed to provide adequate analgesia while minimizing exposure to adverse events.

Navigating and visualizing three-dimensional data sets

This paper provides an overview of the main techniques being used for three-dimensional (3D) visualization of medical data sets and highlights some of the clinical benefits that can be obtained. One of the major advantages of using a 3D representation is that all of the slice data produced by the latest multislice CT and high gradient MR scanners can be utilized, and then presented to the clinician in an intuitive format. Continued advances in technology mean that high resolution 3D representations of patient specific anatomy can now be routinely obtained and so provide valuable input to diagnosis, planning and navigation tasks. Examples from these areas are presented and illustrated below. Future developments and possibilities are also discussed.

The classification of oesophageal 24 h pH measurements using a Kohonen self-organizing feature map

Analysis of 24 h oesophageal pH studies can be problematic with many patients asymptomatic during the investigation, despite observations of reflux. The aim of this study was to carry out a cluster analysis of ambulatory pH studies to determine any underlying patterns and classes within the data. The results of 900 24 h pH studies were investigated using the Kohonen self-organizing feature map (SOFM), a neural network that can be used to identify clusters within multidimensional data. The clinical features were presented to the network and the main classes identified. The SOFM-based analysis showed that patients clinically assessed as having symptomatic reflux during the study could be described by four major classifications. The results also showed that the probability of identifying a correlation between symptoms and reflux during an investigation varies from 0.49 to 0.78 for the classes identified. The developed network may be a useful tool in the classification of pH data. The cluster-based technique may offer an alternative to standard statistical techniques for high-dimensional gastrointestinal data and form the basis of an expert system for the automated analysis of pH data.

A pH-mucosa area unit of measure to consider morphology of the oesophagus when evaluating oesophagitis

Gastro-oesophageal pH measurements are routinely carried out to quantify and determine if levels of acid reflux are responsible for symptoms. Although considered the 'gold standard', evidence suggests that pH measurements do not correlate well with the degree of oesophagitis seen during endoscopy. In this study the current measure of pH was critically examined taking into account both the effects of changes in luminal diameter and endoscopy observations. The oesophageal lumen diameter was investigated using a barium swallow for 25 patients presenting with oesophageal disorders. For each subject the widest luminal diameter was measured for a series of five controlled swallows. The results showed that the lumen diameter varied widely from 0.9 to 3.8 cm. An alternative approach to the current measurement of pH was explored. In this approach the exposure not only included the luminal pH and time exposed but also the area of mucosa exposed as a result of differing luminal diameters. Although it is currently not possible to assess the diameter or morphology of the oesophageal lumen during a pH study, the analysis highlighted that the current measure of pH exposure time does not include the area of mucosa exposed. These results may explain, to some extent, the poor correlation between pH measurements and degree of oesophagitis seen during endoscopy.

Intravenous n-acetylcysteine, ascorbic acid and selenium-based anti-oxidant therapy in severe acute pancreatitis

BACKGROUND

To observe outcome in a cohort of patients with severe acute pancreatitis receiving multiple anti-oxidant therapy.

METHODS

An observational study was carried out in 46 consecutive patients with acute pancreatitis fulfilling current Atlanta consensus criteria for severe disease. All patients received multiple anti-oxidant therapy based on intravenous selenium, N-acetylcysteine and ascorbic acid plus beta-carotene and alpha-tocopherol delivered via nasogastric tube. Principal outcomes were the effect of anti-oxidant supplementation on anti-oxidant levels, morbidity and mortality in patients on anti-oxidant therapy, case-control analysis of observed survival compared to predicted survival derived from logistic organ dysfunction score (LODS), logistic regression analysis of factors influencing outcome and side effect profile of anti-oxidant therapy.

RESULTS

Paired baseline and post-supplementation data were available for 25 patients and revealed that anti-oxidant supplementation restored vitamin C (P = 0.003) and selenium (P = 0.028) toward normal. In univariate survival analysis, patient survival to discharge was best predicted by admission APACHE-II score with relative risk of death increasing 12.6% for each unit increase (95% CI 6.0% to 19.6%). The mean LODS calculated on admission to hospital was 3.7 (standard error of the mean 4.1) giving a predicted mortality for the cohort of 21%. The observed in-hospital mortality was 43%.

CONCLUSIONS

Case-control analyses do not appear to demonstrate any benefit from the multiple anti-oxidant combination of selenium, N-acetylcysteine and ascorbic acid in severe acute pancreatitis.

Small bowel perforation caused by an ingested foreign body masquerading as acute appendicitis

Aman aged 45 years presented with a 9-hour history of lower abdominal pain, which was worse in the right iliac fossa. The pain was sharp in nature and worse with movement. There was no nausea or vomiting. He had previously been well and healthy. On admission, he was apyrexial (37.0°C), had a normal pulse rate (75 beats/min) and was normotensive (120/80 mmHg). Clinical examination was significant for right iliac fossa tenderness but there was no guarding or rebound. There was no blood on urinalysis. His blood tests revealed a raised white cell count (12.4×109/litre), a normal neutrophil count (7.40×109/litre), a raised C-reactive protein (122 mg/litre) and a normal serum amylase (33 U/litre). Erect chest X-ray and plain abdominal X-ray were normal. On re-examination, his pain had worsened and he had increasing peritonism in his right iliac fossa, so he was listed for an urgent appendicectomy.

Effects of a moderate dose of alcohol on simulated laparoscopic surgical performance

BACKGROUND

In medicine, there is no professional regulation of the drinking of alcohol, nor a body of experimental evidence on which such regulation might be based. Here we report the acute and longer-term ("hangover") effects of a moderate dose of alcohol on performance, as assessed objectively on a laparoscopic surgical simulator.

METHODS

In a single-blind, experimental study, medical student subjects were assigned randomly to an alcohol (1.05 mg/kg) or a placebo condition (n = 14 in each). The effects of alcohol on performance on the MIST Virtual Reality surgical simulator were examined 60-90 min and 600-630 min (after a night's sleep) following its ingestion. Measures of the number of errors, time taken, hand movement economy, and excessive use of diathermy were recorded.

RESULTS

On each measure, performance was significantly impaired 60-90 min following alcohol ingestion, but there was no hangover effect 600-630 min later, following a night's sleep. This impairment could not be attributed to between-group differences in either predrink performance, expertise or estimated sleep duration during the night preceding the experimental session.

CONCLUSIONS

Simulated surgical performance is impaired severely when estimated blood alcohol concentration (BAC) is just above the UK legal limit for driving. These results contribute new, objective and quantitative evidence to the current debate about the use and misuse of alcohol within the medical profession.

An investigation into the spatial relationship between complexity and motility within the oesophagus

Nonlinear analysis techniques have recently been used in the characterization of complex physiological signals seen in pathological disorders such as epilepsy and cardiac fibrillation. In this study a series of controlled swallows from an asymptomatic demonstration group was investigated using oesophageal manometry. The nonlinear measure of complexity, largest Lyapunov exponents and phase portraits were then used to explore the complexity of motility patterns at different points within the oesophagus. Results indicate greater complexity within the region of the striated muscle in the upper oesophagus than that observed within the region of smooth muscle in the lower oesophagus. Phase portraits showed that manometry patterns within the asymptomatic demonstration group could be quite different, highlighting the problems in clinical diagnosis. The characterization of motility disorders associated with complex manometry patterns such as diffuse oesophageal spasm (DOS) and nonspecific motility disorder (NOMD) still represents a diagnostic challenge. The use of nonlinear techniques enabling the quantitative and qualitative measurement of oesophageal complexity is considered in the classification of such disorders.

Natural history of adhesional small bowel obstruction: counting the cost

BACKGROUND

The aim of this study was to identify patients admitted with adhesional obstruction to determine if there was an identifiable pattern to the type of initial operation, the type of treatment used for the obstructive episode and the subsequent need for further treatment.

METHODS

Patients with adhesional obstruction were identified retrospectively in a cross-sectional study using ICD codes relating to admissions in the years 1990 to 1996. The case notes were used to assess their outcome.

RESULTS

Fifty-nine case notes from a total of 175 identified initially satisfied the inclusion criteria. These patients had a mean age at presentation of 51 (range 16-88) years and had undergone a total of 122 operations. Thirty-one patients (53 per cent) had a single previous operation with a median time to presentation with obstruction of 5.5 years (range 11 days to 34.7 years); 33 patients (56 per cent) were treated conservatively on their first admission. There was no statistically significant difference in the outcome in patients who received either conservative or surgical treatment. The length of stay in patients treated surgically (median 11 (range 2-47) days) was significantly longer than that for those treated conservatively (median 6 (range 1-39) days) (P< 0.001). A flow chart was constructed demonstrating the eventual outcome of the patients in the study, enabling the cost of adhesional obstruction to be calculated.

CONCLUSION

This type of approach could be used to assess the potential effect of different treatment strategies for adhesional obstruction.

Technical report: The introduction of a new synchronized oesophageal manometry and digital video-fluoroscopy (fluoromanometry) system into the radiology suite

Following the development of a new fluoromanometry system enabling synchronous oesophageal manometry and barium swallow video-fluoroscopy, both the equipment and examination method have been successfully introduced into the radiology suite. The application of the system which uses a PC with video capture and a portable manometry recorder is described together with details of its implementation and the examination technique used.

Progress with cholecystectomy: improving results in England and Wales

BACKGROUND

The Comparative Audit Service of the Royal College of Surgeons of England studied laparoscopic cholecystectomy in England and Wales during 1990-1991. The follow-on study undertaken during 1994 provides data to assess progress.

METHODS

Pro formas were sent to consultant surgeons, requesting data on open and laparoscopic cholecystectomies performed in their units during 1994 with data on mean stay, mortality, complications, and the use of peroperative cholangiography and bile duct exploration. The identity of the consultants was treated confidentially.

RESULTS

Data were provided by 110 surgeons on 4823 cholecystectomies (1019 open and 3804 laparoscopic) and outcome was compared with that of 3319 attempted laparoscopic and 8035 open cholecystectomies carried out during 1990-1991. The proportion of cases attempted laparoscopically rose from 27.2 per cent in 1990-1991 to 78.9 per cent in 1994, and conversion to open cholecystectomy rose from 5.3 to 6.7 per cent respectively. During 1994 peroperative cholangiography was undertaken in 22.9 per cent of laparoscopic and 44.6 per cent of open cases. Complication rates were similar in the two study periods, except the number of reported haemorrhagic complications was reduced by 40 per cent and bile duct injuries by fivefold (from 0.33 to 0.07 per cent).

CONCLUSION

During 1994 the audit sampled approximately 10 per cent of all cholecystectomies performed in England and Wales. The results suggest progress in surgical techniques compared with findings in 1990-1991.

MIST VR: a virtual reality trainer for laparoscopic surgery assesses performance

Images

Synchronous recording and review of oesophageal manometry and video fluoroscopy using a portable manometry recorder and PC with integrated digital video acquisition

We present the technical details of a new system for the synchronous recording and review of a combined oesophageal manometry and video fluoroscopic barium swallow examination. The system developed uses a portable manometry recorder and personal computer (PC) with an integrated digital video acquisition system. These are controlled using software to enable the real time capture of digital video and manometric data throughout the combined examination. The recorded pressure waveforms can then be synchronously displayed on a screen with the recorded digital video of the fluoroscopic barium swallow. This new tool enables both comparative measurement and detailed analysis of the relationship between visualized bolus transport and pressure measurements. It provides for a deeper understanding and improved clinical assessment of complex motility disorders over those obtained when these two modalities are applied separately. The system is easily incorporated into a clinical radiology suite and it is both user and patient friendly. It uses readily available computer hardware together with multimedia software and is a comparatively economical addition to the radiology suite with the manometry analysis available fulfilling the criteria laid down by the Clinical Associates Group of the British Society of Gastroenterology.

A pilot study of antioxidant intake in patients with cholesterol gallstones

Whereas macronutrient intake has been extensively investigated in an attempt to unravel the pathogenesis of human cholesterol gallstones, theoretical considerations and animal models suggest that deficits in micronutrient antioxidants may be more relevant. We report a pilot study of this aspect. The plan was to obtain 7-d weighed food inventories over a 6-mo period from equal numbers of patients who had not consciously changed their diets, patients who were on low-fat diets and age- and gender-matched controls. Food tables would be used to derive daily intakes of 16 known antioxidants, essential amino acids, and essential fatty acids. Under-reporting of food intake, a recognized drawback of this dietary method, would be sought retrospectively by reference to a key publication giving minimum cut-off limits for ratios of energy intakes to basal metabolic rates. There were 18 pairs for study. Analysis of data for the 9 pairs involving patients on their normal diets showed no differences in the intakes of energy macronutrients, and cholesterol, but the patients ingested lower amounts of 10 among 16 antioxidants (P < 0.05 for methionine, alpha-tocopherol, manganese, and vitamin D; 0.05 < P < 0.10 for cysteine, beta-carotene, vitamin C, selenium, zinc, and phosphorus). Both subsets of patients ingested lower amounts of linoleic acid (diet unchanged P = 0.009, changed P = 0.026) and several essential amino acids than did matched controls. Institution of a low-fat diet caused the expected fall in intakes of energy and saturated fatty acids such that the deficit in alpha-tocopherol was amplified, but substitution of fruit and vegetables by the patients resulted in a fortuitous increase in vitamin C, beta-carotene, and manganese intake. Retrospective analysis confirmed under-reporting of food intake by all four subsets of subjects but there was no significant difference in the mean ratio of energy intake to estimated basal metabolic rate in the subset of patients who had not consciously altered their diets and the subset of matched controls. Furthermore, the lower daily intake of alpha-tocopherol and linoleic acid by these patients persisted when results were expressed relative to total fat consumption. The results support the hypothesis that insufficiency of dietary antioxidants, particularly alpha-tocopherol, may be germane to human gallstone disease; they also suggest that low intakes of linoleic acid and essential amino acids may be relevant. Because of the small sample sizes, however, these deductions should be regarded as tentative, pending confirmation by biochemical analysis of blood and especially of hepatic bile.

Critical issues in the management of gastroesophageal reflux disease

AIM

To discuss some of the critical issues in the management of gastroesophageal reflux disease (GERD).

OPINION

GERD is a chronic relapsing disease characterized by pathological exposure of the distal esophagus to gastric acid. Diagnosis of the condition can often be made on the basis of symptomatology alone. Endoscopy can help in assessing the degree of esophageal damage, influencing the choice of therapy, and should be performed at least once during a symptomatic patient's lifetime to exclude a diagnosis of Barrett's esophagus. However, endoscopy is mandatory at diagnosis if alarm symptoms are present. Treatment should aim to provide the lowest degree of acid suppression needed for the control of symptoms. Proton pump inhibitors (PPIs) represent the most cost-effective treatment option for the short- and long-term management of GERD. Compared with standard- and high-dose H2-receptor antagonists, PPIs result in superior and faster healing and symptom relief across all grades of esophagitis and are more effective at maintaining patients in symptomatic and endoscopic remission. Treatment with PPIs has also been shown to reduce the rate of recurrent stricture after initial dilatation. PPIs are generally well tolerated, and to date there have been no reports of gastric dysplasia resulting from their long-term use. Anti-reflux surgery should be reserved for patients who are unresponsive to continuous PPI therapy or perhaps for young patients. It will be several years before the impact of laparoscopic fundoplication as a cost-beneficial therapy for GERD can be assessed.

CONCLUSION

The superior clinical efficacy of PPIs when compared with any other drug regimen for GERD make them the treatment of choice for the short- and long-term management of this troublesome condition.

Prospective audit of perforation rates following upper gastrointestinal endoscopy in two regions of England

After cardiopulmonary complications, perforation is the second most important cause of complications following flexible upper gastrointestinal endoscopy. A recent audit of 14,149 procedures detected a perforation rate of 0.05 per cent (overall mortality rate 0.008 per cent) during diagnostic endoscopy, and a perforation rate of 2.6 per cent (overall mortality rate 1.0 per cent) following oesophageal intubation or dilatation. The incidence of perforation following both diagnostic and therapeutic upper gastrointestinal endoscopy has not changed over the past 10 years. The risk factors are numerous but this audit demonstrated that inexperience increases the likelihood of perforation.

Guidelines on appropriate indications for upper gastrointestinal endoscopy. Working Party of the Joint Committee of the Royal College of Physicians of London, Royal College of Surgeons of England, Royal College of Anaesthetists, Association of Surgeons, the British Society of Gastroenterology, and the Thoracic Society of Great Britain

Upper gastrointestinal endoscopy is a valuable diagnostic tool, but for an endoscopy service to be effective it is essential that it is not overloaded with inappropriately referred patients. A joint working party in Britain has considered the available literature on indications for endoscopy, assessed standard practice through a questionnaire, and audited randomly selected cases using an independent panel of experts and an American database system. They used these data to produce guidelines on the appropriate and inappropriate indications for referral for endoscopy, although they emphasise that under certain circumstances there may be reasons to deviate from the advice given. The need for endoscopy is most difficult to judge in patients with dyspepsia, and this aspect is discussed in detail. Early endoscopy will often prove more cost effective than delaying until the indications are clearer.

Prospective audit of upper gastrointestinal endoscopy in two regions of England: safety, staffing, and sedation methods

A prospective audit of upper gastrointestinal endoscopy in 36 hospitals across two regions provided data from 14,149 gastroscopies of which 1113 procedures were therapeutic and 13,036 were diagnostic. Most patients received gastroscopy under intravenous sedation; midazolam was the preferred agent in the North West and diazepam was preferred in East Anglia. Mean doses of each agent used were 5.7 mg and 13.8 mg respectively, although there was a wide distribution of doses reported. Only half of the patients endoscoped had some form of intravenous access in situ and few were supplied with supplementary oxygen. The death rate from this study for diagnostic endoscopy was 1 in 2000 and the morbidity rate was 1 in 200; cardiorespiratory complications were the most prominent in this group and there was a strong relation between the lack of monitoring and use of high dose benzodiazepines and the occurrence of adverse outcomes. In particular there was a link between the use of local anaesthetic sprays and the development of pneumonia after gastroscopy (p < 0.001). Twenty perforations occurred out of a total of 774 dilatations of which eight patients died (death rate 1 in 100). A number of units were found to have staffing problems, to be lacking in basic facilities, and to have poor or virtually non-existent recovery areas. In addition, a number of junior endoscopists were performing endoscopy unsupervised and with minimal training.

Pathophysiological effects of long-term acid suppression in man

A critical evaluation has been made of the available evidence in man of the effects of prolonged low acid states on the structure and function of the stomach. Various human models have been examined. 1. Ageing does not affect acid output from the normal male stomach, and there may be an increase in women. With progressive atrophy of the corpus mucosa, which is more frequent and rapid in patients with gastric ulcer, there is an associated loss of secretory function. Chronic gastritis and atrophy are the most important age-related changes, which in many cultures are hypothesized to develop via a prior Helicobacter pylori-related gastritis. However, H. pylori colonization of the mucosa decreases with increasing grades of gastric atrophy probably because intestinal metaplasia provides a hostile environment. Atrophy and intestinal metaplasia are associated with precancerous lesions and gastric cancer. Apparent hyperplasia of the gastric argyrophil endocrine cells is a common and spontaneous phenomenon in patients with atrophic gastritis, which in part may be related to the preferential loss of nonendocrine cells. 2. Pernicious anemia is associated with a complete lack of acid production, marked hypergastrinemia, and endocrine cell hyperplasia in the majority of patients. ECL-cell carcinoids and gastric cancer occur with a prevalence of 3-7%, and endoscopic surveillance in routine clinical practice is not warranted. 3. Gastric ECL-cell carcinoids are rare events that have been described in association with two diseases in man, pernicious anemia and Zollinger-Ellison syndrome as part of multiple endocrine neoplasia syndrome type I, and usually relate to marked hypergastrinemia and the presence of chronic atrophic gastritis with gastric antibodies or a genetic defect rather than the presence or absence of acid. Regression or disappearance of ECL-cell carcinoids, either spontaneously or after removal of the gastrin drive, has been recorded. Lymph node, and rarely hepatic, metastases are documented but death in these cases has been anecdotal. 4. Therapy with H2 antagonists may result in up to a twofold rise in serum gastrin levels but in man no endocrine cell hyperplasia has been recorded. However, the data for H2 antagonists on these aspects are very limited. There is no drug-related risk of gastric or esophageal cancer, although the incidence of the latter may be raised. Long-term treatment with omeprazole is associated with a two- to fourfold increase in gastrin levels over baseline values in one third of patients and apparent endocrine cell hyperplasia in 7% of cases overall.(ABSTRACT TRUNCATED AT 400 WORDS)

Appropriate use of upper gastrointestinal endoscopy--a prospective audit. Steering Group of the Upper Gastrointestinal Endoscopy Audit Committee

Work by this group has shown that there is a wide range of opinion as to patients' suitability for endoscopy. In a recent study, 1297 questionnaires were sent to a random selection of doctors, including 350 general physicians, 400 surgeons, 477 gastroenterologists, and 70 general practitioners. The respondent was asked to indicate whether or not he would refer the patient described by each case vignette for endoscopy. Depending on the indication, the positive referral rate varied from 4.5% to 99% overall, and from 4.5% to 63.8% for all those clinical situations that the working party felt to be inappropriate. A second study examined the appropriateness of 400 consecutive cases referred from four units within one health region; these cases were judged independently, and without conferring, by a panel of seven gastroenterologists. The same cases were rated by software that incorporated American opinion (the Rand criteria). Although only 45 (11%) of the cases were classed as inappropriate by the British panel, 120 cases (31%) assessed by the American software were rated inappropriate. These differences occurred largely because in the USA it is recommended that one month's antiulcer treatment be tried before considering endoscopy for dyspepsia and thus many referrals were seen as inappropriate by the American database. Of the 45 cases found to be inappropriate by the British doctors no important abnormality was found at endoscopy; whereas of 120 cases judged inappropriate by the Rand criteria, three duodenal and two gastric ulcers, and one gastric cancer were diagnosed at gastroscopy. This study attempts a quantitative assessment of inappropriate use and serves to encourage further work to define appropriateness.

Inflammatory pseudotumour of the liver: antecedent causes and clinical experience

We present a case in which inflammatory pseudotumour of the liver which appears to complicate Caroli's disease. We have reviewed the literature in hepatic inflammatory pseudotumour with particular emphasis on underlying causes. We were able to find 45 reported cases, with adequate clinical data in 42; in these only 7 showed a probable antecedent cause. There were gallstones in another 5, giving a prevalence not significantly different to that within the general population. Hepatic inflammatory pseudotumour typically presents with a history of fever, anorexia, loss of weight, hepatic pain, jaundice and a detectable liver mass (or masses). The diagnosis of inflammatory pseudotumour should be particularly considered when there is a history of previous inflammatory hepato-biliary disease. Preoperative or intra-operative diagnosis might then avoid major hepatic surgery.

Vitamin C status in patients with acute pancreatitis

Vitamin C is a key antioxidant in human blood plasma and hence could influence the outcome of conditions such as acute pancreatitis in which oxidative stress apparently plays a pivotal role. The concentrations of vitamin C and its immediately bioavailable form, ascorbic acid, in fasting plasma samples from 30 healthy volunteers were compared with those in admission samples from 29 consecutive patients with acute pancreatitis and 27 patients with other acute abdominal crises. Median (range) levels of vitamin C and ascorbic acid, respectively, were 15 (6.3-19) and 12 (4.5-18) micrograms/ml in the control group, 2.8 (0.3-10) and < 0.5 (< 0.5-6.0) micrograms/ml in patients with acute pancreatitis, and 3.7 (0.6-15) and 2.3 (< 0.5-15) micrograms/ml in those with other acute abdominal problems. Admission plasma samples showed equally low vitamin C levels in both groups of patients (P < 0.001 versus controls), but those from patients with acute pancreatitis were further characterized by a disproportionate reduction in ascorbic acid, such that the concentration of ascorbic acid and its ratio to vitamin C were both significantly lower than in samples from patients with an acute abdomen (P < 0.005 and P < 0.001 respectively). It is concluded that the stress of an acute intra-abdominal crisis is accompanied by a non-specific decrease in the plasma level of vitamin C. In acute pancreatitis early and profound oxidative stress compounds this problem by denaturing the available vitamin. There may be a case for the judicious parenteral administration of ascorbic acid to patients with acute pancreatitis to boost plasma antioxidant defence.

Hypogastrinemia and esophageal atresia

To investigate extraesophageal anomalies in infants with esophageal atresia, preoperative plasma gastrin was measured in 12 infants. The median plasma gastrin was 32 ng/L (interquartile range, 24 to 44). There was significant correlation with birth weight (rs = .73, P less than .05) and gestational age (rs = .74, P less than .05). Within this group 9 infants of greater than 36 weeks' gestation were matched to a group of 20 control infants without esophageal atresia. Infants with esophageal atresia had a significantly lower median plasma gastrin (38 ng/L v 55 ng/L, P less than .05). This may indicate preexisting vagal abnormalities in esophageal atresia unrelated to surgical intervention.

A comparison of the frequency of stress ulceration and secondary pneumonia in sucralfate- or ranitidine-treated intensive care unit patients

OBJECTIVE

To compare the frequency of acute stress ulceration and secondary pneumonia caused by aerobic Gram-negative bacilli in ICU patients treated with either sucralfate or ranitidine.

DESIGN

Prospective, randomized study.

SETTING

ICU, university hospital.

PATIENTS

Sixty adult patients who were mechanically ventilated and at risk of developing stress ulceration.

INTERVENTION

The patients were randomized to receive either sucralfate (1 g every 6 hrs) via the nasogastric tube or iv ranitidine (50 mg every 6 hrs). If the gastric pH was less than 3.5 in the latter group, 30 mL of 0.3M sodium citrate was given via the nasogastric tube.

MEASUREMENTS AND MAIN RESULTS

On admission, the frequency rate of erosion/ulceration (assessed with the endoscope) was 13.5%. After 4 days, this rate had increased to 18% in sucralfate-treated patients and 36% in ranitidine-treated patients (NS). Mean gastric pH was more alkaline in the ranitidine-treated patients (5.50) compared with the sucralfate-treated patients (4.26) (p less than .01). This pH permitted a higher occurrence rate of gastric colonization by aerobic Gram-negative bacilli in ranitidine-treated patients (64.3%) compared with sucralfate-treated patients (23.8%) (p less than .01). Retrograde bacterial colonization from the stomach to oropharynx and trachea occurred more frequently in ranitidine-treated patients compared with sucralfate-treated patients. Ultimately, the occurrence rate of pneumonia was greater in the ranitidine-treated (35.7%) than in the sucralfate-treated patients (10.3%) (p less than .05).

CONCLUSION

Based on our findings, we recommend the adoption of sucralfate for routine prophylaxis against stress ulceration.

Recommendations for standards of sedation and patient monitoring during gastrointestinal endoscopy

(1) Safety and monitoring should be part of a quality assurance programme for endoscopy units. (2) Resuscitation equipment and drugs must be available in the endoscopy and recovery areas. (3) Staff of all grades and disciplines should be familiar with resuscitation methods and undergo periodic retraining. (4) Equipment and drugs necessary for the maintenance of airway, breathing, and circulation should be present in the endoscopy unit and recovery area (if outside the unit) and checked regularly. (5) A qualified nurse, trained in endoscopic techniques and adequately trained in resuscitation techniques, should monitor the patient's condition during procedures. (6) Before endoscopy, adverse risk factors should be identified. This may be aided by the use of a check list. (7) The dosage of all drugs should be kept to the minimum necessary. There is evidence that benzodiazepine/opioid mixtures are hazardous. (8) Specific antagonists for benzodiazepines and opioids exist and should be available in the event of emergency. (9) A cannula should be placed in a vein during endoscopy on 'at risk' patients. (10) Oxygen enriched air should be given to 'at risk' patients undergoing endoscopic procedures. (11) The endoscopist should ensure the well being and clinical observation of the patient undergoing endoscopy in conjunction with another individual. This individual should be a qualified nurse trained in endoscopic techniques or another medically qualified practitioner. (12) Monitoring techniques such as pulse oximetry are recommended. (13) Clinical monitoring of the patient must be continued into the recovery area. (14) Records of management and outcome should be collected and will provide data for appropriate audit.

Current and future drugs for acid-peptic disease: a plethora of opinions on possible mechanisms of action

Sixty-seven invited participants involved in the development, evaluation, and use of therapies for acid-peptic disorders participated in a meeting to discuss the scientific basis for healing actions of ulcer drugs and the prospects for future developments ("Realities of Mucosal Protection in the Upper Gastrointestinal Tract," Lausanne, Switzerland, November 8-10, 1987). Eighty-one key statements were prepared and subsequently analyzed on the basis of a voting system. Of the 45 statements that dealt with existing therapies, only 3 statements showed positive consensus (agreement of two-thirds or more of voters) about mechanisms of ulcer healing. Participants agreed that both (1) hydrogen/potassium adenosine triphosphatase inhibitors and (2) histamine H2 antagonists healed ulcers solely by acid inhibition, and (3) that sucralfate works by topical action. Substantial uncertainty about the mechanisms by which bismuth compounds and antacids heal ulcers was noted as well as their wide range of effects. The mechanism of ulcer healing by prostaglandins and the clinical relevance of antiulcer effects of drugs demonstrated in acute studies with animals were also controversial. There was greater agreement among participants about unexplored drug effects that might produce ulcer healing. Of the 36 such mechanisms surveyed, the most support went to therapies aimed at enhancement of mucosal blood flow, epithelial restitution, and mucosal alkaline secretion or inhibition of luminal pepsin activity. The diversity of opinions among participants suggests a high level of empiricism in the development of ulcer healing drugs apart from those that inhibit acid secretion. This empiricism probably arises from inadequate understanding of processes of mucosal injury and repair.

Midazolam and flumazenil in gastroenterology

Flumazenil, a specific benzodiazepine antagonist, has been used to reverse sedation in a double-blind, controlled study of patients undergoing upper gastrointestinal (GI) endoscopy. Forty patients in each of two centres were given a standard dose of either flumazenil (n = 40) or placebo (n = 40) after gastroscopy under midazolam sedation. Assessments were made of degree of sedation, psychomotor ability and amnesia up to 24 h after endoscopy. In patients treated with flumazenil, sedation was effectively reversed within 5 min in 77.5% of cases compared to 27.5% of patients treated with placebo. The difference was both clinically and statistically significant at 5 and 30 min but not at 60 min after reversal. There was no evidence of resedation 18 to 24 h later. Times to complete Trieger dot-joining tests were significantly faster in the flumazenil group at 5, 30 and 60 min. Amnesia for the procedure was retained but did not occur for events after administration of flumazenil. The only adverse event was severe pain in the arm of one patient during the injection of flumazenil. Flumazenil rapidly and safely reverses midazolam-induced sedation while retaining amnesia for gastroscopy.

Preference for hot drinks is associated with peptic disease

The temperature at which people chose to take a hot drink was measured in 59 patients with endoscopically proven peptic disorders of the upper gastrointestinal tract and 65 asymptomatic controls. The patients in the disease group drank significantly hotter tea or coffee than the control group (medians 62 degrees and 56 degrees Celsius respectively, P less than 0.0001). The median temperatures of choice for subgroups of patients with oesophageal, gastric or duodenal disease were significantly higher than the control group (63.5 degrees, 63 degrees, 60.5 degrees C respectively). There was no relationship between a preference for hotter drinks with either the sex or smoking habits of the patient. In the control group the temperature of choice tended to decrease with age though linear regression just failed to reach statistical significance (p = 0.06); this trend was not apparent in the disease group (p = 0.64). Thermal injury as a result of drinking hot fluids may be a causative factor in some peptic disorders.

Multichannel digital recording of intraluminal temperature in the upper gastrointestinal tract of man: techniques and analyses

A recording system has been developed to measure intraluminal temperature changes from six sites simultaneously in the upper gastrointestinal tract at rates up to 10 Hz from each site. The temperature probe contains six type K thermocouples mounted in 14 French gauge orogastric tube. The data is logged, after digital conversion and signal multiplexing, onto disc storage by a dedicated microcomputer. The fluctuating temperature profile, defined as temperature spikes, has been subjected to novel computer analysis to allow definition of temperature load and dissipation within the oesophagus, stomach and duodenum. This system enables the effects of drinking and eating hot and cold foods on the physiological functions of the gastrointestinal tract to be studied accurately.

Electrodes for 24 hours pH monitoring--a comparative study

Three pH electrodes in clinical use were examined--(1) antimony electrode with remote reference electrode (Synectics 0011), (2) glass electrode with remote reference electrode (Microelectrodes Inc. MI 506) and (3) combined glass electrode with integral reference electrode (Radiometer GK2801C). In vitro studies showed that both glass electrodes were similar and superior to the antimony electrode with respect to response time, drift, and sensitivity. The effect of the siting of the reference electrode on the recorded pH was examined in five human volunteers. The pH reading using a remote skin reference electrode was higher by a mean of 0.3 pH units (range 0.0-0.6) in the stomach, lower by 0.65 pH units (0.5-0.8) in the duodenum and lower by 0.3 pH units (0.0-0.6) in the oesophagus than that simultaneously obtained with an intraluminal reference electrode. Buccal reference electrodes gave similar readings to skin. Combined reference and glass pH electrodes are recommended for 24-hour ambulatory pH monitoring.

Duodenal pH in health and duodenal ulcer disease: effect of a meal, Coca-Cola, smoking, and cimetidine

Intraluminal duodenal pH was recorded using a combined miniature electrode and logged digitally every 10 or 20 seconds for five hours (basal/meal/drink) in eight control subjects and 11 patients with duodenal ulcer (five on and off treatment with cimetidine). Over the whole test there were no significant differences in duodenal mean pH or log mean hydrogen ion activity (LMHa) between control subjects and patients with duodenal ulcer, but there were significantly longer periods of duodenal acidification (pH less than 4) and paradoxically more periods of duodenal alkalinisation (pH greater than 6) in the duodenal ulcer group compared with controls. After a meal duodenal mean pH and LMHa fell significantly in both controls and patients with duodenal ulcer, with more periods of duodenal acidification and alkalinisation in the duodenal ulcer group. An exogenous acid load (Coca-Cola) significantly increased the periods of duodenal acidification, and reduced alkalinisation, in both groups. Cimetidine significantly increased mean pH and LMHa and abolished the brief spikes of acidification in four of five patients with duodenal ulcer. Peak acid output (but not basal acid output) was significantly correlated with duodenal mean pH and LMHa but not with the periods of duodenal acidification. Smoking did not affect duodenal pH in either group.

Comparison of midazolam and diazepam in doses of comparable potency during gastroscopy

The water soluble benzodiazepine midazolam was compared with diazepam, in doses of 0.07 mg kg-1 and 0.15 mg kg-1 respectively, administered i.v. to 100 patients undergoing gastroscopy. The degree of sedation, ease of endoscopy and recovery were comparable in the two groups. The effects of both drugs on arterial pressure were similar. Compared with diazepam, midazolam had a faster onset of effect, caused virtually no pain on injection, and provided a greater degree of amnesia.

Midazolam and diazepam for gastroscopy

Midazolam 0.1 mg/kg was compared with diazepam 0.15 mg/kg intravenously in patients undergoing gastroscopy. The patients receiving midazolam were more sedated at the end of the procedure. The mean discharge times from the clinic for diazepam and midazolam patients were 85 and 102 minutes, respectively. The principal differences between the two drugs were that midazolam had a faster rate of onset, was virtually free from venous complications, provided much better amnesia (90% compared with 50%), and although the recovery time was longer with midazolam, the rate of recovery during the period of observation was faster. Neither drug caused any significant cardiorespiratory depression.

Gastric acid regulates the release of plasma secretin in man

Fasting plasma secretin determined in nine healthy subjects, twelve patients with active duodenal ulcer and four with Zollinger-Ellison syndrome were 3.2 +/- 0.4, 5.1 +/- 1.2 and 20.3 +/- 1.3 pmol/l respectively (mean +/- SEM). Cimetidine significantly (P less than 0.05) reduced levels in those with duodenal ulcer, as did gastric aspiration in the Zollinger-Ellison group. A significant correlation (P less than 0.001) was found between basal acid output and mean fasting plasma secretin. After a solid meal and subsequent liquid soft drink, no sustained mean rise in plasma secretin was observed; changes in secretin appeared to coincide in time with rapid falls in duodenal pH, though little relationship could be established between the absolute level of pH and changes in plasma secretin. The mean peak post-prandial rise in plasma secretin observed after solids was significantly (P less than 0.05) greater in duodenal ulcer patients than controls (9.1 +/- 1.1 versus 6.7 +/- 0.5 pmol/l) as was the mean integrated post-prandial release (1002 +/- 110 versus 710 +/- 67 pmol min-1 1(-1)). Cimetidine reduced both rises (P less than 0.05) and was associated with significantly less duodenal pH readings below 4 (P less than 0.001). These results suggest that gastric acid is a major release mechanism for plasma secretin both fasting and after meals but it is likely the acid load rather than absolute pH in the duodenum which determines circulating levels.

The effect of salbutamol and propranolol on pentagastrin, histamine and meal-stimulated acid and pepsin secretion in the dog

The beta 2 adrenergic agonist Salbutamol was infused intravenously in doses of 0.05, 0.1 and 0.2 microgram/kg-min in conscious dogs with gastric fistulae. Salbutamol inhibited meal-stimulated acid (measured with intragastric titration) by up to 82%. Salbutamol produced dose-related inhibition of acid stimulated by pentagastrin (up to 88%) and by histamine (up to 52%). Pepsin secretion in response to histamine (but not pentagastrin) was also inhibited by salbutamol. The salbutamol infusion caused a marked tachycardia, an increase in pulse pressure, slight hyperkalaemia and hyperglycaemia. The beta-adrenergic antagonist propranolol augmented pentagastrin-stimulated acid and inhibited meal-stimulated secretion. Propranolol abolished salbutamol - induced tachycardia, and blocked the inhibition by salbutamol of pentagastrin-stimulated acid. Salbutamol inhibition of acid in the dog provides further support for the hypothesis that there are beta 2-adrenergic receptors in the stomach.

Effects of gastrointestinal hormones on fasting gallbladder storage patterns in man

Gallbladder storage and emptying patterns were studied in fasting normal subjects by a duodenal perfusion technique using indocyanine green as a biliary marker. Fasting gallbladder storage patterns were very variable but a more uniform biliary output with net storage of about 40% of the biliary marker was observed during a simulated interprandial state (2--4 h after meals) produced by a low dose intravenous infusion of secretin and caerulein. With this background hormonal stimulation, infusion of bovine pancreatic polypeptide to achieve physiological interprandial levels promoted further gallbladder storage of bile. Bovine pancreatic polypeptide produced storage by a major effect on the gallbladder rather than on the liver, common bile duct or sphincter of Oddi since a reduction of biliary output was not observed during bovine pancreatic polypeptide infusion in cholecystectomized subjects. Bovine pancreatic polypeptide had a separate effect on the pancreas, reducing trypsin output in both normal and cholecystectomized subjects.