Analysing risk factors for urinary tract infection based on automated monitoring of hospital-acquired infection.

Urinary tract infections account for as much as one-third of all nosocomial infections. The aim of this study was to examine previously reported characteristics of patients with hospital-acquired urinary tract infections (HA-UTI) using an automated infection monitoring system (Hospital-Acquired Infection Registry: HAIR). A matched case-control study was conducted to investigate the association of risk factors with HA-UTI. Patients with HA-UTI more frequently had indwelling urinary catheters or a disease in the genitourinary or nervous system than the controls. Automated hospital-acquired infection monitoring enables documentation of key risk factors to better evaluate infection control interventions in general or for selected groups of patients.

Incidence rates of hospital-acquired urinary tract and bloodstream infections generated by automated compilation of electronically available healthcare data.

BACKGROUND: Monitoring of hospital-acquired infection (HAI) by automated compilation of registry data may address the disadvantages of laborious, costly and potentially subjective and often random sampling of data by manual surveillance. AIM: To evaluate a system for automated monitoring of hospital-acquired urinary tract (HA-UTI) and bloodstream infections (HA-BSI) and to report incidence rates over a five-year period in a Danish hospital trust. METHODS: Based primarily on electronically available data relating to microbiology results and antibiotic prescriptions, the automated monitoring of HA-UTIs and HA-BSIs was validated against data from six previous point-prevalence surveys (PPS) from 2010 to 2013 and data from a manual assessment (HA-UTI only) of one department of internal medicine from January 2010. Incidence rates (infections per 1000 bed-days) from 2010 to 2014 were calculated. FINDINGS: Compared with the PPSs, the automated monitoring showed a sensitivity of 88% in detecting UTI in general, 78% in detecting HA-UTI, and 100% in detecting BSI in general. The monthly incidence rates varied between 4.14 and 6.61 per 1000 bed-days for HA-UTI and between 0.09 and 1.25 per 1000 bed-days for HA-BSI. CONCLUSION: Replacing PPSs with automated monitoring of HAIs may provide better and more objective data and constitute a promising foundation for individual patient risk analyses and epidemiological studies. Automated monitoring may be universally applicable in hospitals with electronic databases comprising microbiological findings, admission data, and antibiotic prescriptions.

Surveillance of selected post-caesarean infections based on electronic registries: validation study including post-discharge infections.

The importance of surveillance of post-discharge infections has increased as a consequence of shorter hospital stay after surgical procedures. This study examined the ability of a computer-based surveillance system to identify urinary tract infections (UTIs) and postoperative wound infections (PWIs) within 30 days after caesarean section. We assessed the use of data from various electronic registries to identify patients with post-caesarean UTI and PWI classified according to a reference standard. The standard was based on information from medical records and self-reported data (questionnaire) using modified Centers for Disease Control and Prevention definitions. The sensitivity of the computer system in detecting UTI diagnosed during hospital stay, readmission or at visits to hospital outpatient clinics was 80.0%; the specificity was 99.9%. For post-discharge UTIs diagnosed outside the hospital, sensitivity and specificity were 76.3% and 99.9%, respectively. For PWIs diagnosed in hospital and post-discharge outside hospital, sensitivities were 77.1% and 68.9%, and the specificities 99.5% and 98.2%. We conclude that a computer-based surveillance system may identify in-hospital infections and post-discharge infections with a relatively high sensitivity and excellent specificity.

Surveillance of hospital-acquired infections based on electronic hospital registries.

Computer-assisted surveillance of hospital-acquired infections (HAIs) was compared with conventional manual registration (our gold standard i.e. reference method) by chart reviews of nosocomial infections in patients from surgical and medical departments. By combining selected infection parameters from various electronic hospital registries, the computer detected general HAIs with a sensitivity of 94% and a specificity of 47%. However, defining septicaemia, urinary tract infection (UTI), pneumonia and postoperative wound infection (PWI) specifically by sets of simplified criteria (infection parameters), computer-assisted surveillance was able to detect these infections with a sensitivity ranging between 82% (UTI) and 100% (septicaemia), and a specificity ranging between 91% (PWI) and 100% (septicaemia) compared with conventional manual registration. We conclude that computer surveillance based on data collected for other purposes in electronic hospital registries is an effective method for monitoring HAIs.

Malabsorption of fat after partial gastric resection. A study of pathophysiologic mechanisms.

The causes of fat malabsorption after gastric resection were studied in patients randomized to Billroth I gastroduodenostomy or Roux-en-Y gastrojejunostomy after antrectomy and selective gastric vagotomy for intractable prepyloric peptic ulcer. Eighteen patients were studied 2 years or more postoperatively. Assessment of food intake concerning protein, fat, carbohydrate, vitamins and minerals showed deficiency in seven cases, but without significant difference between the two operation types. Postoperative weight loss did not differ significantly between the two study groups, but the faecal excretion of fat was significantly larger (p less than 0.05) after gastrojejunostomy than after gastroduodenostomy. Since both the oro-caecal transit time and the breath excretion of hydrogen after a standardized test meal showed no intergroup difference, the results suggest that duodenal exclusion may be of particular pathophysiologic importance for the observed malabsorption of fat after gastric resection.

Effects of some gastrointestinal peptides on isolated human and rabbit gastric glands.

The isolated gastric gland preparation, with aminopyrine accumulation as an index of the parietal cell response, has been used to study the effects of somatostatin (S-14), gastrin-releasing peptide (GRP), cholecystokinin (CCK-8), vasoactive intestinal peptide (VIP), and peptide YY (PYY) on the in vitro acid secretion in human and rabbit oxyntic mucosa. Somatostatin was able to inhibit the parietal cell response to histamine in both human and rabbit isolated gastric glands (maximal inhibition, 22% and 34%, respectively) but failed to inhibit the parietal cell response to db-cAMP. However, other peptides capable of inhibiting gastric acid secretion in vivo, such as CCK, VIP, and PYY, were unable to induce any inhibition of the parietal cell response to db-cAMP or histamine in the isolated gastric gland preparation irrespective of the species studied. GRP was not able to induce a parietal cell response, a finding that is in accord with the assumption that the stimulatory effect of GRP on gastric acid secretion in vivo is by releasing gastrin from antral G-cells.

Evaluation of propranolol for prevention of recurrent bleeding from esophageal varices between sclerotherapy sessions.

Forty-one patients admitted with first episode of bleeding from esophageal varices were enrolled in a trial of the efficacy of oral propranolol to prevent rebleeding during the course of endoscopic sclerotherapy until obliteration. Single-blind randomization to sclerotherapy alone or with propranolol was used. At monthly endoscopy the varices were injected with 1% Aethoxysclerol until obliteration. If bleeding recurred, additional sclerotherapy was given. There was no intergroup difference in time to eradication of varices (8.1 vs. 7.7 months). The cumulative number of bleedings from varices and from distal esophageal ulcerations was identical in the two study groups. Five patients in the control group but only one in the propranolol group died of bleeding in the study period, a difference of only borderline significance (chi 2 = 4.08, df = 1). There were no specific side effects of propranolol. Thus propranolol did not significantly reduce the frequency of rebleeding until variceal obliteration, but could have had some influence on the gravity of rebleeding.

Palliative endoscopic dilatation in carcinoma of the esophagus and esophagogastric junction.

The palliative effect of repeated endoscopic dilatation of malignant strictures of the esophagus and esophagogastric junction was prospectively evaluated in 41 patients. Dilatation was performed with Eder-Puestow technique in brief general anesthesia. Substantial improvement in swallowing ability was experienced after each treatment. The dysphagia recurred, however, and the dilatations were repeated at intervals of about 4 weeks. Most patients required less than or equal to three treatments during their remaining lifespan. There were few complications, the most prominent being perforation (in 5% of 128 sessions). Only short hospital stay was required, and 18 patients remained at home during the periods between dilatations. Endoscopic dilation of the esophagus and esophagogastric junction gives good palliation. The technique is simple, cheap and safe. It is suitable for lesions at any site, not time-consuming, available at almost all endoscopy units, and consequently to be recommended in this clinical setting.

The pentagastrin-induced gastric acid response in humans.

The pentagastrin-induced acid response, alone and versus different doses of cimetidine, was studied in humans. The inhibitory effect of the histamine H2-receptor antagonist cimetidine could only in part be counteracted by increasing doses of pentagastrin. The maximal gastric acid response was significantly decreased by cimetidine, and the ED50 values for pentagastrin showed a minor but still statistically significant increase, indicating both a competitive and a non-competitive inhibition by cimetidine of pentagastrin-induced gastric acid secretion. The pA2 characterization of the receptor mediating the pentagastrin-induced gastric acid response gave a value of 6.2, compared with the pA2 value of the human H2 receptor of 6.1. This suggests that the pentagastrin-induced gastric acid response in humans is mediated via the histamine H2-receptor.

Histamine H2-receptor of human and rabbit parietal cells.

The histamine H2-receptor on the human parietal cell has been characterized by using dose-response curves and the negative logarithm of the molar concentration of an antagonist (pA2) analyses of cimetidine antagonism of betazole, histamine, and impromidine stimulation in isolated human and rabbit gastric glands. To evaluate the in vitro results, betazole-stimulated gastric acid secretion with and without cimetidine was also studied in healthy subjects. In the in vivo model, individual dose-response curves were shifted to the right with increasing cimetidine concentrations, but this was counteracted by increasing betazole doses, indicating competitive, reversible antagonism. The pA2 values ranged from 6.1 to 6.3. In isolated human gastric glands, impromidine was shown to be eight times more potent than histamine, indicating higher receptor affinity, but the maximally stimulated aminopyrine accumulation was the same as for histamine, and the pA2 values for cimetidine antagonism did not differ significantly, i.e., 5.7 (histamine) and 6.1 (impromidine). In isolated rabbit gastric glands, cimetidine inhibited the histamine- and impromidine-stimulated response with pA2 values of 6.0 and 7.3, respectively. Impromidine was shown to be approximately 100 times more potent than in human gastric glands, whereas histamine had the same potency. This confirms the role of the histamine H2-receptor and suggests a difference between the species concerning receptor affinity.

Antibiotic prophylaxis in high-risk gastric surgery. A prospective, randomized clinical comparison of cefuroxime and doxycycline.

The efficacy of two antibiotics as prophylaxis in high-risk gastric surgery was evaluated in a prospective, randomized trial: 400 mg doxycycline in a single dose (98 patients) was compared with 1.5 g cefuroxime given twice with an 8-hour interval (101 patients). The two groups were comparable in regard to all relevant factors of importance for susceptibility to infection. The incidence of postoperative abdominal infection was 8.2% in the doxycycline group and 7.9% in the cefuroxime group. The most common extraabdominal infectious complications were in the lungs (20% of the patients in both groups). No subgroup of patients was identifiable in which one antibiotic was superior to the other. The efficacy of the two investigated prophylaxis regimens was apparently identical.

Further observations on cerebral or retinal ischemia in patients with right-left intracardiac shunts.

Between October 1983 and November 1986, 20 patients suspected of having a paradoxical cerebral or retinal embolism were identified. Cerebral infarction was the most common presentation. Six patients had a patent foramen ovale demonstrated by cardiac catheterization or surgery. Three patients had a newly discovered atrial septal defect, and one had an atrial septal defect that had previously been treated surgically. Results of the cardiac physical examination, chest roentgenography, and electrocardiography were unremarkable in 12 patients. Eighteen patients had a right-to-left shunt demonstrated by contrast echocardiography. Nine of these patients underwent cardiac catheterization; seven had abnormal catheterization study results: four had a patent foramen ovale and three had an atrial septal defect. Sixteen patients received medical therapy only while four underwent surgery. All patients survived the initial insult. There were no deaths or ischemic recurrences on follow-up ranging from one month to three years. We believe that contrast echocardiography can provide important diagnostic information, even in situations in which cardiac involvement is not suspected. Additional studies are needed before the optimal treatment of presumptive paradoxical cerebral embolism can be determined.

Measurement of pouch volume and stoma diameter after gastroplasty.

A balloon technique has been developed for measurement of the pouch volume and stoma diameter after gastroplasty. Twenty-seven patients prospectively included in a randomized study of two types of gastroplasty operation have been investigated 6 months postoperatively. During the operation the proximal pouch was calibrated to be about 40 ml and the stoma diameter to 11 min. Six months after the operation the patients had on average reduced weight by 29 kg. Using the balloon technique, the stoma diameter was 12 +/- 1.6 (s.e.m.) mm and the pouch volume 80 +/- 11.0 ml. There was a significant correlation between the stoma diameter and weight reduction during the first 6 months postoperatively (P less than 0.01). The relationship between the stoma diameter and weight reduction followed best an exponential equation. No correlation was found between the pouch volume and weight reduction. The presented technique for measurement of pouch volume and stoma diameter after gastroplasty may be an important tool to evaluate the influence of various factors on the long-term results of surgical treatment for morbid obesity.

Stereological investigations on human gastric mucosa: I. Normal oxyntic mucosa.

Quantitative morphological data on normal human oxyntic mucosa were obtained from endoscopic biopsies in ten healthy male volunteers. Corpus mucosa was biopsied in the resting state and during maximal acid secretion and then processed for light and electron microscopy. Stereological analyses were carried out on sections comprising the entire thickness of the epithelial layer. About one-third of the mucosal volume was taken up by lamina propria and 15% by parietal cells. Counts of cells that displayed their nucleus in the sections revealed that in average of 12% of the epithelial cells were parietal cells, 43% were mucous cells, 40% were zymogen cells, and 4% were endocrine cells. Parietal cells displaying two nuclei were twice as large as those with only one nucleus. Six percent of the parietal cell volume was taken up by the nucleus, and 33% of the cytoplasmic volume was occupied by mitochondria. Stimulation of acid secretion resulted in a 76% increase in the secretory surface density; simultaneously there was a slight decrease in the mean size of the parietal cells and an increase in the relative volume of the nucleus. During maximal stimulation of acid the parietal cells from the superficial mucosal layers displayed a 40% larger secretory surface than those from the deeper parts of the mucosa. The data, which will serve as a basis for studies of pathological mucosae, are compared with those obtained in other species.

Inhibitory action of omeprazole on acid formation in gastric glands and on H+,K+-ATPase isolated from human gastric mucosa.

The inhibitory effect of omeprazole on acid formation has been studied in vitro in gastric glands and partly purified H+,K+-ATPase, prepared from mucosa obtained either from healthy subjects by gastroscopic biopsy or from gastric ulcer patients during antrectomy. The effect of omeprazole was compared with the inhibitory pattern of the H2-antagonist cimetidine. Acid production in the glands was determined by measuring the accumulation of 14C-aminopyrine. In glands isolated from patients, omeprazole inhibited acid production maximally stimulated by histamine, db-cAMP, and potassium in a dose-dependent manner, with an IC50 value of about 50 nM irrespective of the agonist used. In contrast, cimetidine inhibited only histamine-induced aminopyrine accumulation, with an IC50 of about 30 micron. The inhibitory effect of omeprazole in db-cAMP-stimulated glands from healthy volunteers was of the same magnitude as seen in glands from gastric ulcer patients. Basal aminopyrine accumulation in glands from both patients and healthy volunteers was almost totally inhibited by omeprazole, whereas cimetidine was without effect. Omeprazole also concentration-dependently inhibited the H+,K+-ATPase activity in isolated gastric membrane vesicles. The estimated IC50 value was 4 micron.

Acid secretion in isolated gastric glands from healthy subjects and ulcer patients.

Isolated human gastric glands provide an in vitro model that can yield significant information about the mechanisms regulating gastric acid secretion at the parietal cell level. Aminopyrine, a weak base that accumulates in acid compartments, has been used as an indirect probe of H+ secretion. By means of a microscale technique it was possible to isolate oxyntic glands from gastroscopic biopsy specimens and thereby enable studies of healthy subjects and non-operated ulcer patients. Histamine (5.4 X 10(-5) M) and db-cAMP (10(-3) M) both induced a pronounced response, whereas the response to carbachol (4.5 X 10(-6) M), although still statistically significant, was less potent. The response to stimuli was twice as high in duodenal ulcer patients as in normal individuals. In contrast, the response in patients with a gastric ulcer located either in the prepyloric region or at the minor curvature on the antrum-corpus border was of the same magnitude as in healthy subjects. Pentagastrin did not induce any response in isolated gastric glands from normal individuals. Gastric acid secretion in vitro, measured as aminopyrine accumulation, did not decrease with increasing age of the individuals.