Perioperative optimization and profitability (POP) in a high-volume bariatric surgery center.

BACKGROUND: Currently, bariatric surgery is the most effective long-term treatment of obesity. Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the primary types of bariatric surgery performed worldwide. To minimize the risks of surgical complications and optimize cost-effectiveness, it is essential to develop fast-track protocols and patient logistics. At Aleris Hospitals in Denmark, a fast-track methodology in bariatric surgery has been implemented and continuously optimized over the last 15 years. The main objective was to demonstrate timelines recorded during one consecutive year in a fast-track, high-volume bariatric surgery setting after logistic optimization. METHODS: This study included 949 consecutive patients who had undergone primary bariatric surgery in 2021. The primary outcomes were length of hospital stay and perioperative timeline recordings that were prospectively collected. The secondary outcomes were mortality, complication rates, and weight loss data. RESULTS: The vast majority of our patients (99.1%) were discharged from the hospital within the day after surgery. The median total surgery time was 30 min, after 12 min of patient preparation and with a turnover time between patients of seven min. The median knife-to-knife time in one operating room was 56 min. Mortality was zero, 30-day reoperation rate was 1.2%, and 30-day readmission rate was 0.8%. SG and RYGB patients had an excess weight loss after four months of 45.6% and 57.9%, respectively. CONCLUSION: Implementation of fast-track principles in the clinical practice of bariatric surgery allows for an optimized, cost-effective surgical organization supporting the quality of procedures and patient safety.

Physical training following gastric bypass: effects on physical activity and quality of life-a randomized controlled trial.

BACKGROUND: Obesity is associated with physical inactivity and impaired health-related quality of life (HRQoL). We aim to test the hypothesis that Roux-en-Y gastric bypass (RYGB) followed by supervised physical training improves physical activity (PA) levels and HRQoL. METHODS: Sixty patients, qualified for RYGB, were at 6 months post-surgery randomized to 26 weeks of a supervised physical training intervention (INT) or to a control (CON) group. PA was assessed by accelerometry and using the questionnaire RPAQ. HRQoL was measured by the SF-36 questionnaire. All assessments were performed pre-surgery and 6, 12, and 24 months post-surgery. RESULTS: RYGB did not improve objectively or self-reported PA, but improved all domains of SF-36 (all p < 0.01). Objectively measured light PA, moderate to vigorous PA, and step counts tended to increase in INT compared to CON 12 months after RYGB (0.05 < p < 0.09), but the effects failed to persist. The SF-36 domain "general health" increased in INT compared to CON 24 months after RYGB (p = 0.041). CONCLUSION: RYGB improves HRQoL, but does not increase PA. Supervised physical training intervention improves general health 24 months after RYGB and tends to improve certain domains of PA right after the intervention period, but fails to increase the patients' overall PA level over time. Clinical Trial Registration Registered at ClinicalTrials.gov-no. NCT01690728.

Laparoscopic repair of paraesophageal hernia with anterior gastropexy: a multicenter study.

BACKGROUND: The approach to repair of paraesophageal hernias (PEHs) is controversial. Recent data suggest that mesh repair leads to recurrence rates similar to non-mesh approaches, while subjecting patients to mesh-associated complications. Routine fundoplication during PEH repair has been favored despite significant dysphagia rates. We present our multicenter prospective data on laparoscopic PEH repairs using a modified Boerema anterior gastropexy without fundoplication. METHODS: We prospectively followed patients after modified Boerema PEH repair at three institutions. Patient demographics, perioperative data, and postoperative outcomes were evaluated. Subjective and objective outcomes were assessed via clinical assessment, follow-up questioning, endoscopy, and radiographic swallow studies. RESULTS: A total of 101 patients were followed a mean of 10.8 (median, 12) months. We encountered 9 (8.9%) intraoperative complications and 13 (12.9%) postoperative complications. There was no mortality. Reflux symptoms were absent in 71 patients (70.3%) postoperatively. Of the remaining subjects, 8 (7.9%) had mild intermittent reflux without the need for proton pump inhibitors (PPI), 12 (11.9%) had moderate reflux necessitating PPI as needed, and 10 (9.9%) had reflux requiring daily PPI. Our recurrence rate, assessed at postoperative endoscopy/barium swallow, was 16.8%. Of these, 10 (9.9%) were small segmental recurrences and 7 (6.9%) were large recurrences. CONCLUSION: Herein, we demonstrate a favorable recurrence rate while avoiding the potential major complications associated with mesh hiatoplasty. Our data tend to support a tailored approach to incorporation of fundoplication during PEH repair. Postoperative acid reflux was absent in most of our patients, and pharmacotherapy alone was sufficient for those experiencing reflux symptoms.

Incidence of adenocarcinoma among patients with Barrett's esophagus.

BACKGROUND: Accurate population-based data are needed on the incidence of esophageal adenocarcinoma and high-grade dysplasia among patients with Barrett's esophagus. METHODS: We conducted a nationwide, population-based, cohort study involving all patients with Barrett's esophagus in Denmark during the period from 1992 through 2009, using data from the Danish Pathology Registry and the Danish Cancer Registry. We determined the incidence rates (numbers of cases per 1000 person-years) of adenocarcinoma and high-grade dysplasia. As a measure of relative risk, standardized incidence ratios were calculated with the use of national cancer rates in Denmark during the study period. RESULTS: We identified 11,028 patients with Barrett's esophagus and analyzed their data for a median of 5.2 years. Within the first year after the index endoscopy, 131 new cases of adenocarcinoma were diagnosed. During subsequent years, 66 new adenocarcinomas were detected, yielding an incidence rate for adenocarcinoma of 1.2 cases per 1000 person-years (95% confidence interval [CI], 0.9 to 1.5). As compared with the risk in the general population, the relative risk of adenocarcinoma among patients with Barrett's esophagus was 11.3 (95% CI, 8.8 to 14.4). The annual risk of esophageal adenocarcinoma was 0.12% (95% CI, 0.09 to 0.15). Detection of low-grade dysplasia on the index endoscopy was associated with an incidence rate for adenocarcinoma of 5.1 cases per 1000 person-years. In contrast, the incidence rate among patients without dysplasia was 1.0 case per 1000 person-years. Risk estimates for patients with high-grade dysplasia were slightly higher. CONCLUSIONS: Barrett's esophagus is a strong risk factor for esophageal adenocarcinoma, but the absolute annual risk, 0.12%, is much lower than the assumed risk of 0.5%, which is the basis for current surveillance guidelines. Data from the current study call into question the rationale for ongoing surveillance in patients who have Barrett's esophagus without dysplasia. (Funded by the Clinical Institute, University of Aarhus, Aarhus, Denmark.).

Quantitative histological assessment of hepatic ischemia-reperfusion injuries following ischemic pre- and post-conditioning in the rat liver.

BACKGROUND: Ischemic preconditioning (IPC) has been shown to protect the liver against ischemia-reperfusion (I/R) injuries. However, ischemic post-conditioning has received little attention. The aim of the present study was to quantify and compare the hepato-protective properties of IPC and IPO, for the first time, using unbiased design-based stereological methods. METHODS: We divided 67 rats into four groups: sham, liver ischemia (LI), IPC, and IPO. Rats were subjected to 60 min LI, followed by 4- or 24-h reperfusion. We performed quantification of (NVR) and apoptotic cell profile number. RESULTS: We observed no significant differences in NVR between ischemic groups after 4 h. After 24-h reperfusion, NVR had increased to 70% in the LI group, compared with 51% (P = 0.02) and 49% (P = 0.01) in the IPC and IPO groups, respectively. After 4-h reperfusion, the apoptotic cell number was significantly higher in all ischemic groups than in the sham group; we detected no difference between ischemic groups. After 24-h reperfusion, we detected a significantly lower number of apoptotic cell profiles in the IPC group than in the LI group (P = 0.02). The mean number of apoptotic cell profiles decreased insignificantly in the IPO group (P = 0.06). Liver parameters were at all time comparable between groups. CONCLUSIONS: After I/R, IPC and IPO reduce the degree of hepatocellular injury. Both methods are equally efficient at preventing hepatocellular necrosis. Furthermore, apoptosis is significantly lower after IPC.

Randomized clinical trial: inhibition of the TRPV1 system in patients with nonerosive gastroesophageal reflux disease and a partial response to PPI treatment is not associated with analgesia to esophageal experimental pain.

OBJECTIVE: Many patients with nonerosive reflux disease (NERD) have insufficient relief on proton pump inhibitors (PPIs). Some patients have a hypersensitive esophagus and may respond to transient receptor potential vanilloid 1 (TRPV1) antagonists. Aim. To investigate the effect of the TRPV1 antagonist AZD1386 on experimental esophageal pain in NERD patients. MATERIAL AND METHODS: Enrolled patients had NERD and a partial PPI response (moderate-to-severe heartburn or regurgitation ≥3 days/week before enrolment despite ≥6 weeks' PPI therapy). Fourteen patients (21-69 years, 9 women) were block-randomized into this placebo-controlled, double-blinded, crossover study examining efficacy of a single dose (95 mg) of AZD1386. On treatment days, each participant's esophagus was stimulated with heat, distension, and electrical current at teaching hospitals in Denmark and Sweden. Heat and pressure pain served as somatic control stimuli. Per protocol results were analyzed. RESULTS: Of 14 randomized patients, 12 were treated with AZD1386. In the esophagus AZD1386 did not significantly change the moderate pain threshold for heat [-3%, 95% confidence interval (CI), -22;20%], distension (-11%, 95% CI, -28;10%), or electrical current (6%, 95% CI, -10;25%). Mean cutaneous heat tolerance increased by 4.9°C (95% CI, 3.7;6.2°C). AZD1386 increased the maximum body temperature by a mean of 0.59°C (95% CI, 0.40-0.79°C), normalizing within 4 h. CONCLUSIONS: AZD1386 had no analgesic effect on experimental esophageal pain in patients with NERD and a partial PPI response, whereas it increased cutaneous heat tolerance. TRPV1 does not play a major role in heat-, mechanically and electrically evoked esophageal pain in these patients. ClinicalTrials.gov identifier: D9127C00002.

Complications in Patients Undergoing Laparoscopic Bariatric Surgery in an ERABS-optimized, High-Volume, Single Center During 2020 and 2021.

PURPOSE: Complication rates after fast-track optimization in bariatric surgery are varying. The aim of this study was to identify short-term complications in patients undergoing laparoscopic sleeve gastrectomy (SG) in an ERABS (enhanced recovery after bariatric surgery) optimized setup. MATERIALS AND METHODS: This study is an observational analysis of a consecutive cohort of 1600 patients undergoing SG at an ERABS-optimized, private hospital during 2020 and 2021. Primary outcomes were length of stay, mortality, readmissions, reoperations, and complications according to the Clavien-Dindo classification (CDC) within postoperative day (POD) 30 and 90. Secondary outcomes were weight loss and quality of life (QoL) according to Moorehead-Ardelt questionnaires during the first postoperative year. RESULTS: Primary outcomes: 99.1% of patients were discharged within POD 1. The 90-day mortality rate was zero. There were 1% readmissions and 1.2% reoperations within POD 30. Total 30-day complication rate was 4.6%, where 3.4% accounted for CDC grades ≤ II, and 1.3% accounted for CDC grade III. There were zero grade IV-V complications. SECONDARY OUTCOMES: One year after surgery, weight loss was substantial (p < 0.001), with an excess weight loss of 71.9%, and QoL had significantly increased (p < 0.001). CONCLUSION: This study demonstrates that the use of an ERABS protocol in bariatric surgery does not compromise neither safety nor efficacy. Complication rates were low, and weight loss was significant. This study thus provides strong arguments that ERABS programs are beneficial in bariatric surgery.

Ischemic pre- and postconditioning has pronounced effects on gene expression profiles in the rat liver after ischemia/reperfusion.

Ischemic pre (IPC)- and postconditioning (IPO) protect the liver against ischemia/reperfusion injuries (IRI). Conditioning involves several different trigger factors, mediators, and effectors, many of which are affected during the early phase of reperfusion, ultimately resulting in decreased liver injuries. The aim of the present study was to investigate the genomic response induced by IPC and IPO in ischemia/reperfusion-damaged rat liver biopsies. Forty-eight male Wistar rats were divided into five groups: sham (n = 8), IRI (n = 10), IPC (n = 10), IPO (n = 10), and IPC + IPO (n = 10). The rat livers were subjected to 30 min of ischemia. Liver biopsies and blood samples were taken after 30 min of reperfusion. The biopsies were analyzed using cDNA microarrays with validation by quantitative RT-PCR. The significance analysis of microarray was used to identify genes with changed expression levels. A comparison analysis of the intervention groups showed a highly increased number of genes, with significantly different expression in the conditioned groups compared with the IRI group. A total of 172 genes were identified as the most highly affected, and these genes showed similar patterns with regard to the up- and downregulated expression levels within the conditioned groups. Pathway analysis of the 172 genes identified four networks that were involved in increased gene expression, cellular growth, and proliferation. In conclusion, the present study demonstrated that IPC, IPO, and IPC + IPO had pronounced effects on the expression levels of a large number of genes during early reperfusion. IPC, IPO, and IPC + IPO seem to mediate their protective effects by regulating the same genes and genetic networks. These identified networks are known to be involved in maintaining cellular homeostasis.

Effects of ischemic pre- and postconditioning on HIF-1α, VEGF and TGF-ß expression after warm ischemia and reperfusion in the rat liver.

BACKGROUND: Ischemic pre- and postconditioning protects the liver against ischemia/reperfusion injuries. The aim of the present study was to examine how ischemic pre- and postconditioning affects gene expression of hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor A (VEGF-A) and transforming growth factor ß (TGF-ß) in liver tissue. METHODS: 28 rats were randomized into five groups: control; ischemia/reperfusion; ischemic preconditioning (IPC); ischemic postconditioning (IPO); combined IPC and IPO. IPC consisted of 10 min of ischemia and 10 min of reperfusion. IPO consisted of three cycles of 30 sec. reperfusion and 30 sec. of ischemia. RESULTS: HIF-1α mRNA expression was significantly increased after liver ischemia compared to controls (p = 0.010). HIF-1α mRNA expression was significantly lower in groups subjected to IPC or combined IPC and IPO when compared to the ischemia/reperfusion group (p = 0.002). VEGF-A mRNA expression increased in the ischemia/reperfusion or combined IPC and IPO groups when compared to the control group (p < 0.05). CONCLUSION: Ischemic conditioning seems to prevent HIF-1α mRNA induction in the rat liver after ischemia and reperfusion. This suggests that the protective effects of ischemic conditioning do not involve the HIF-1 system. On the other hand, the magnitude of the HIF-1α response might be a marker for the degree of I/R injuries after liver ischemia. Further studies are needed to clarify this issue.

Long-term complications to reflux disease in community practice. A 17-year cohort study of 4706 patients.

OBJECTIVE: To examine the risk of developing strictures in patients with erosive and non-erosive gastroesophageal reflux disease in a community-based setting, since controlled trials indicate that the use of proton pump inhibitors renders the risk of strictures insignificant. MATERIAL AND METHODS: A 17-year cohort study of 4706 patients referred to endoscopy due to upper GI symptoms, with a population comparison cohort of 47,060 individuals. All patients were followed and treated according to prevailing guidelines by their usual care provider. Main outcomes were relative risks (RR) and 95% confidence intervals (CI) for incident strictures and dilatations. RESULTS: 776 (16.5%) patients were diagnosed with erosive esophagitis, particularly men (61.2%). Over a period of 1-17 years (mean 10.5), 20 patients (2.6%) in the esophagitis group developed a peptic stricture, necessitating one or more dilatations in 16 patients (2.1%). Among the non-esophagitis patients, the incidences for both outcomes were 1.2%. Male gender doubled the risk of developing strictures, and alcohol abuse raised the risk four folds. Erosive patients had a risk of developing strictures eight times (95% CI: 5.0-13.0) higher than controls, whereas non-erosive patients' risk was 4.0 (95% CI: 2.8-5.7). The majority of strictures developed within the first 10 years after a diagnosis of esophagitis. CONCLUSION: Patients with esophagitis had eight times higher risk of strictures than population controls and two times higher than dyspeptic patients without esophagitis. This indicates that long-term outcomes in general practice are poorer than in controlled trials, most likely due to a lack of compliance with medication.

The esophageal multimodal pain model: normal values and degree of sensitization in healthy young male volunteers.

BACKGROUND: Sensory changes are thought to be involved in gastro-esophageal reflux disease (GERD). The esophageal multimodal pain model can be used to investigate sensations in response to distension, heat, electric current and acid. AIMS: The aim of this study was to provide normal values for this model in the normal state and in the acid induced sensitized state. METHODS: Fifty-three healthy men (20-38 years old) underwent esophageal stimulation with distension, heat and electrical current before and after sensitization with 0.1 N HCl acid. Stimulus intensities at painful and non-painful thresholds and referred pain areas were measured. The percentage of individual participants sensitized to each modality was calculated. In 22 subjects the pre-acid tests were repeated on three subsequent visits. RESULTS: To reach moderate pain, subjects tolerated mean distension of 29.1 ± 11 mL, heat stimulation time of 141 ± 33 s, and mean current of 17.6 ± 6.4 mA. After acid exposure, significantly reduced thresholds were observed for mechanical (24%), heat (11%) and electrical (14%) stimulation (P values < 0.05). The percentage of subjects sensitized, defined as reductions in thresholds of ≥10% or ≥20% after acid perfusion, was as follows: for distension 77%/62%, for heat 48%/28%, and for current 58%/44%. The model showed good reliability (intra-class correlations >0.6). CONCLUSIONS: Normal values for healthy young men are now provided for the normal and the sensitized state. The percentage of subjects sensitized after acid stimulation are thoroughly documented, and depends on stimulation type and the cut-off value chosen.

The impact of constructive feedback on training in gastrointestinal endoscopy using high-fidelity Virtual-Reality simulation: a randomised controlled trial.

BACKGROUND: Recently, virtual reality computer simulators have been used to enhance traditional endoscopy teaching. Previous studies have demonstrated construct validity of these systems and transfer of virtual skills to the operating room. However, to date no simulator-training curricula have been designed and there is very little evidence on the impact of external feedback on acquisition of endoscopic skills. The aim of the present study was to assess the impact of external feedback on the learning curves on a VR colonoscopy simulator using inexperienced trainees. MATERIALS AND METHODS: 22 trainees, without colonoscopy experience were randomised to a group which received structured feedback provided by an experienced supervisor and a controlled group. All participants performed 15 repetitions of task 3 from the Introduction colonoscopy module of the Accu Touch Endoscopy simulator. Retention/transfer tests on simulator were performed 4-6 weeks after the last repetition. The proficiency levels were based on the performance of eight experienced colonoscopists. RESULTS: All subjects were able to complete the procedure on the simulator. There were no perforations in the feedback group versus seven in the non-feedback group. Subjects in the feedback group reached expert proficiency levels in percentage of mucosa visualised and time to reach the caecum significantly faster compared with the control group. None of the groups demonstrated significant degradation of performance in simulator retention/transfer tests. CONCLUSION: Concurrent feedback given by supervisor concur an advantage in acquisition of basic colonoscopy skills and achieving of proficiency level as compared to independent training.

Warm-up in a virtual reality environment improves performance in the operating room.

OBJECTIVE: To assess the impact of warm-up on laparoscopic performance in the operating room (OR). BACKGROUND: Implementation of simulation-based training into clinical practice remains limited despite evidence to show that the improvement in skills is transferred to the OR. The aim of this study was to evaluate the impact of a short virtual reality warm-up training program on laparoscopic performance in the OP. METHODS: Sixteen Laparoscopic Cholecystectomies were performed by 8 surgeons in the OR. Participants were randomized to a group which received a preprocedure warm-up using a virtual reality simulator and no warm-up group. After the initial laparoscopic cholecystectomy all surgeons served as their own controls by performing another procedure with or without preoperative warm-up. All OR procedures were videotaped and assessed by 2 independent observers using the generic OSATS global rating scale (from 7 to 35). RESULTS: There was significantly better surgical performance on the laparoscopic Cholecystectomy following preoperative warm-up, median 28.5 (range = 18.5-32.0) versus median 19.25 (range = 15-31.5), P = 0.042. The results demonstrated excellent reliability of the assessment tool used (Cronbach's alpha = 0.92). CONCLUSION: This study showed a significant beneficial impact of warm-up on laparoscopic performance in the OP. The suggested program is short, easy to perform, and therefore realistic to implement in the daily life in a busy surgical department. This will potentially improve the procedural outcome and contribute to improved patient safety and better utilization of OR resources.

Descending inhibitory pain modulation is impaired in patients with chronic pancreatitis.

BACKGROUND & AIMS: Pain is a prominent symptom in chronic pancreatitis (CP), but the underlying mechanisms are incompletely understood. We investigated the role of descending pain modulation from supraspinal structures as well as central nervous system sensitization in patients with pain from CP. METHODS: Twenty-five patients with CP and 15 healthy volunteers were included. Descending pain modulation was investigated by diffuse noxious inhibitory control (a descending inhibitory response after conditioning stimulation). Central pain processing was investigated as the perceptual responses to multimodal (electrical, thermal, and mechanical) stimulations of the rectosigmoid and evoked brain potentials after electrical stimulation of the rectosigmoid. RESULTS: Compared with healthy volunteers, the efficacy of diffuse noxious inhibitory control was reduced in patients with CP (13% +/- 21% vs 39% +/- 22%, respectively; F = 3.8; P = .01); central sensitization was indicated by remote hyperalgesia in the rectosigmoid to electrical stimulation (21 +/- 15 mA vs 27 +/- 15 mA; F = 6.2; P = .02) and heat stimulation (51 degrees C +/- 5 degrees C vs 53 degrees C +/- 4 degrees C; F = 5.9; P = .02). Compared with controls, patients with CP had increased latency of the early P1 peak to rectosigmoid stimulation (85 +/- 21 ms vs 108 +/- 28 ms, respectively; P = .02), possibly reflecting reorganization of central pain pathways. CONCLUSIONS: Patients with CP have impairments in inhibitory pain modulation and evidence of central sensitization. Treatment of their pain therefore should focus not only on the pancreas, but also on descending pain modulation from supraspinal structures and central nervous system sensitization.

Acid hypersensitivity in patients with eosinophilic oesophagitis.

OBJECTIVE: Painful symptoms are prevalent in patients with eosinophilic oesophagitis but experimental data are sparse. The aim of this study was to compare the pain response to experimental oesophageal stimulation in 14 patients with eosinophilic oesophagitis and 15 healthy volunteers. MATERIAL AND METHODS: A multimodal probe was placed in the oesophagus. The participants were subjected to mechanical, thermal and electrical pain stimuli followed by perfusion with 0.1 M HCl. Pain scores, referred pain areas and evoked brain potentials to electrical stimulation of the oesophagus were recorded. RESULTS: Patients tolerated significantly less acid perfused in the oesophagus (median 123 versus 200 ml; P = 0.02) and felt the burning sensation evoked by the acid earlier (median 2.0 versus 5.0 min; P = 0.01). Eight patients had coexisting gastro-oesophageal reflux disease. Six patients had pure eosinophilic oesophagitis, and this group felt the acid earlier than those with concomitant reflux or the healthy volunteers (median 0.8 versus 2.0 and 5.0 min; P = 0.03). There were no differences between patients and controls in the responses to mechanical or thermal stimulation (P > 0.4). Furthermore, no differences were found for the proxies of central nervous system sensitization (response to electrical stimulations, referred pain areas or evoked brain potentials; P > 0.1). CONCLUSIONS: Patients with eosinophilic oesophagitis are hypersensitive to acid perfused in the oesophagus, and pathophysiologic findings are likely confined to the peripheral tissue. Reflux from physiological acid may play a role in the symptoms of eosinophilic oesophagitis.

Assessment of early learning curves among nurses and physicians using a high-fidelity virtual-reality colonoscopy simulator.

BACKGROUND: Recently, it has been suggested that nurses can perform diagnostic endoscopy procedures, which traditionally have been a physician's responsibility. The existing studies concerning quality of sigmoidoscopy performed by nurses are small, used assessment tools with insufficient validation and to date there is very little knowledge of the learning curve patterns for physicians and nurses. The aim of a present study was to assess early learning curves on a virtual-reality colonoscopy simulator of untrained residents as compared with that of nurses with and without endoscopy assistance experience. MATERIALS AND METHODS: Thirty subjects were included in the study: 10 female residents (median age 30.5 years) without colonoscopy experience, 10 female nurses (median age 27.5 years) without endoscopy assistance experience and 10 female nurses (median age 42 years) with endoscopy assistance experience. All participants performed 10 repetitions of task 6 from the "Introduction" colonoscopy module of the Accu Touch Endoscopy simulator. Eight experienced colonoscopists performed three repetitions of task 6 in order to provide the reference expert level of performance. RESULTS: All subjects completed the virtual colonoscopy without complications. Significant differences existed between residents and nurses with respect to time to complete the procedure. Residents and nurses showed similar learning curve patterns. There were not significant differences between the groups in terms of volume of insufflated air, percentage of time without discomfort, and percentage of mucosa seen. None of the trainee groups achieved expert proficiency level in terms of time and amount of insufflated air by the tenth repetition. CONCLUSIONS: Nurses performed virtual colonoscopy as accurately and safely as residents. Although the residents performed significantly faster, time differences showed a tendency towards decreasing, and appraisement of the numeric time differences seemed of minor practical importance. From a technical point of view this indicates that nurses may learn to perform colonoscopy after appropriate training.

Expression of genes involved in rat liver angiogenesis after ischaemia and reperfusion: effects of ischaemic pre- and post-conditioning.

BACKGROUND: During surgery, ischaemic pre- (IPC) and post-conditioning (IPO) protects the liver against ischaemia/reperfusion injuries (I/R-injuries). The impact of ischaemic conditioning on liver regeneration has been less well studied. Angiogenesis is an important part of liver regeneration after hepatectomy. The aim of the present study was to investigate the effect of ischaemia/reperfusion and ischaemic conditioning on the expression of genes with angiogenic potential in a model of rat liver ischaemia. METHODS: A model of total liver ischaemia (30 min) and reperfusion (30 min) was employed using Wistar rats. Rats were randomized into five groups: (C) control (IRI) ischaemic, IPC, IPO and IPC + IPO. Liver enzymes were sampled at the end of reperfusion. Liver biopsies were analysed using cDNA microarrays. RESULTS: Alanine aminotransferase (ALT) increased significantly in all the ischaemic groups compared with controls (P= 0.000). Searching databases 99 genes involved in rat liver angiogenesis were identified. Compared with group (C) the number of genes significantly up-regulated was as follows: IRI (n= 5), IPC (n= 24), IPO (n= 33) and IPC + IPO (n= 18). No genes were down-regulated in the four groups compared with controls. CONCLUSION: Ischaemic conditioning, as demonstrated in the present study, seems to be potent activators of angiogenic genes. This might be favourable to the regenerating liver.

Reductions in plasmin inhibitor and fibrinogen predict the improved fibrin clot lysis 6 months after obesity surgery.

Prothrombotic and metabolic variables are decreased after obesity surgery, and fibrin clot lysis is increased. It is unknown how fibrinolytic variables are affected, and whether fibrinolytic and metabolic changes predict the enhanced clot lysis. Study aims were to determine fibrinolytic biomarkers before and 6 months after Roux-en-Y gastric bypass (RYGB) and to identify predictors of the RYGB-induced increase in clot lysis. Women (n = 42) and men (n = 18) with obesity underwent RYGB, and factor XIII (FXIII), thrombin activatable fibrinolysis inhibitor (TAFI), plasminogen and plasmin inhibitor (PI) were measured before and 6 months after surgery. Regression analyses identified determinants of the RYGB-induced increase in clot lysis among changes in fibrinogen and in fibrinolytic and metabolic variables. Results showed that after RYGB, FXIII, TAFI, plasminogen and PI were reduced (P < .0005). Reductions in PI (ß = -0.59) and fibrinogen (ß = -0.35), together with age (ß = -0.22) and male sex (ß = 0.22), predicted the enhanced clot lysis with the model explaining 56% (P < .0005). Predictors of the reduction in PI were reductions in cholesterol (ß = 0.37) and glucose (ß = 0.29), together with male sex (ß = -0.28), whereas reductions in fibrinogen were predicted by lowering of interleukin-6 (IL-6) (ß = 0.32). In conclusion, fibrinolytic variables were reduced 6 months after RYGB. Targeting PI and fibrinogen, by reducing metabolic variables such as glucose, cholesterol and IL-6, has a profibrinolytic effect in obesity.

Somatosensory hypersensitivity in the referred pain area in patients with chronic biliary pain and a sphincter of Oddi dysfunction: new aspects of an almost forgotten pathogenetic mechanism.

BACKGROUND AND AIMS: Somatosensory hyperalgesia in the referred pain area (RPA) in patients with acute or chronic abdominal pain syndromes may result from the convergence of nerve fibers from visceral and somatic tissues at the spinal and supraspinal levels. Chronic biliary pain in patients with the postcholecystectomy syndrome (i.e., biliary hypersensitivity) may be explained by persistent hyperexcitability of neurons in the central nervous system (CNS). The aim of this study was to evaluate the cutaneous neural sensory perception in the RPA in patients with chronic postcholecystectomy biliary pain and a sphincter of Oddi (SO) dysfunction (SOD). METHODS: Forty-two patients with persistent biliary pain and suspected SOD, 27 age-matched healthy volunteers, and 18 age-matched asymptomatic cholecystectomized controls were prospectively investigated by quantitative sensory testing (Neurometer CPT). The biliary symptoms and the severity of pain were classified on a visual analog pain severity scale system via a previously validated and standardized questionnaire. The patients helped the doctors locate the RPA in the right upper quadrant. The sensory detection threshold was determined noninvasively (Neurometer CPT) with transcutaneous electrical stimulation at 5, 250, and 2,000 Hz, and different current intensities (range from 0.01 to 9.99 mA) applied in a single (patient) blinded method. These three frequencies selectively excite small unmyelinated (C fibers), small myelinated (A-delta), and large myelinated (A-beta) fibers, which transmit dull pain, sharp pain, and touch, respectively. The contralateral region of the abdomen left upper quadrant served as the control area. The sensory current perception threshold ratio (SCPTR) of the data measured in the contralateral area and the RPA was calculated. RESULTS: The SCPTRs in the definite SOD patients with biliary pain, healthy volunteers, the asymptomatic cholecystectomized controls, and the symptomatic cholecystectomized patients but without SOD were 2.32 +/- 1.4 versus 1.06 +/- 0.24 versus 0.97 +/- 0.16 versus 0.83 +/- 0.35 at 2,000 Hz; 2.19 +/- 1.0 versus 1.01 +/- 0.26 versus 1.02 +/- 0.25 versus 0.88 +/- 0.35 at 250 Hz; and 2.19 +/- 1.1 versus 1.12 +/- 0.26 versus 0.99 +/- 0.37 versus 0.84 +/- 0.32 at 5 Hz, respectively. Significant hypersensitivity was detected in the RPA at different stimulation frequencies in the SOD patients with biliary pain versus the cholecystectomized controls: at 5 Hz: P = 0.00001; at 250 Hz: P = 0.00001; and at 2,000 Hz: P = 0.0001, respectively. CONCLUSION: Continuous visceral pain (biliary pain) caused by local inflammatory/sensitizing processes or a CNS malfunction could lead to significant hypersensitivity of the peripheral nociceptive nerve fibers in SOD patients. Postcholecystectomy pain may be explained by persistent hyperexcitability of the nociceptive neurons in the CNS with or without objective motility disorders of the SO.

Metabolic changes in the pig liver during warm ischemia and reperfusion measured by microdialysis.

AIM: Portal triad clamping can cause ischemia-reperfusion injury. The aim of the study was to monitor metabolic changes by microdialysis before, during, and after warm ischemia in the pigliver. MATERIAL AND METHODS: Eight pigs underwent laparotomy followed by ischemia by Pringle's maneuver. One microdialysis catheter was placed in each of four liver lobes. A reference catheter was placed in a muscle. Microdialysis samples were collected at intervals of 30 min starting 2 h before 1 h of total ischemia followed by 3 h of reperfusion. Glucose, lactate, pyruvate, and glycerol concentrations were measured. Blood samples were drawn for determination of alanine aminotransferase, alkaline phosphatase, and bilirubin together with total leukocytes and prothrombin time. RESULTS: All parameters were stable during the baseline period. During the ischemic period, lactate levels increased significantly (P < 0.05) followed by a rapid decrease after reperfusion. A transient increase was observed for glucose and glycerol. Pyruvate showed a slight increase from the time of ischemia. The lactate-pyruvate ratio increased rapidly after initiating ischemia and decreased immediately after reperfusion. A slight increase in transaminase levels was observed. CONCLUSIONS: During and after warm ischemia, there were profound metabolic changes in the pigliver observed with an increase in lactate, glucose, glycerol, and the lactate-pyruvate ratio. There were no differences between the four liver lobes, indicating the piglivers homogeneity.