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Background Acute mesenteric ischemia represents a life-threatening gastrointestinal condition. A noninvasive diagnostic modality that identifies mesenteric ischemia patients early in the disease process will enable early surgical intervention. Previous studies have identified significant changes in the small-bowel electrical slow-wave parameters during intestinal ischemia caused by total occlusion of the superior mesenteric artery. The purpose of this study was to use noninvasive biomagnetic techniques to assess functional physiological changes in intestinal slow waves in response to partial mesenteric ischemia. Methods We induced progressive intestinal ischemia in normal porcine subjects (n = 10) by slowly increasing the occlusion of the superior mesenteric artery at the following percentages of baseline flow: 50%, 75%, 90%, and 100% while simultaneous transabdominal magnetoenterogram (MENG) and serosal electromyogram (EMG) recordings were being obtained. Results A statistically significant serosal EMG amplitude decrease was observed at 100% occlusion compared with baseline, whereas no significant change was observed for MENG amplitude at any progressive occlusion levels. MENG recordings showed significant changes in the frequency and percentage of power distributed in bradyenteric and normoenteric frequency ranges at 50%, 75%, 90%, and 100% vessel occlusions. In serosal EMG recordings, a similar percent power distribution (PPD) effect was observed at 75%, 90%, and 100% occlusion levels. Serosal EMG showed a statistically significant increase in tachyenteric PPD at 90% and 100% occlusion. We observed significant increase in tachyenteric PPD only at the 100% occlusion level in MENG recordings. Conclusions Ischemic changes in the intestinal slow wave can be detected early and noninvasively even with partial vascular occlusion. Our results suggest that noninvasive MENG may be useful for clinical diagnosis of partial mesenteric ischemia.

Background Appropriate patient selection is crucial to the success of bariatric surgery (BaS). The objective of this study was to identify risk factors for increased post-operative mortality in patients undergoing BaS using a nationally representative sample. Materials and methods BaS patients ≥18 years old in the United States were identified from the 2001 Nationwide Inpatient Sample (NIS). The effect of gender, age, insurance status, and need for re-operation on post-operative mortality was examined using a multivariate logistic regression model. Results A national cohort of 54,878 patients was identified with age 41 ± 0.2 years (mean ± SE), 84% women, length of stay (LOS) 3.9 ± 0.2 days, and overall mortality of 4 per 1,000 BaS patients. Mean LOS of those who died was 17.6 ± 3.7 days. Adjusting for comorbidities and demographics, men had increased likelihood of death [odds ratio (OR) 2.1, 95% confidence interval (CI) 1.1–4.3, P P P P P Conclusion Based on national data, risk factors for increased post-operative mortality in BaS patients include male gender, age >39 years, Medicaid insured, and need for re-operation. These data can assist in optimizing BaS patient outcomes.

Previous studies involving basic electrical rhythm (BER) have not been carried out far enough to fully characterize the relationship between mesenteric ischemia and BER. The phenomenon of reperfusion injury has also not been correlated with BER activity. The goal of this study was to characterize changes in BER during mesenteric ischemia and reperfusion and to correlate them with changes in pathology.Serosal electrodes were used to record the electrical activity of rabbit jejunum (n = 20) at baseline, during ischemia (90-210 min), and during reperfusion (120-240 min). BER frequency and amplitude were monitored, and biopsies were taken at the end of ischemia and reperfusion. A pathologist blinded to the specimen identity graded the histology on a scale of 0 (no changes) to 6 (transmural necrosis). Paired t test, the Kruskal-Wallis test of non-parametric ranks, and Fisher's r to z test were used for statistical significance where appropriate.BER frequency and amplitude fell significantly after 15 min of ischemia and became undetectable by 90 min of ischemia in all animals. The likelihood that BER would return during reperfusion was highly correlated with length of ischemia (r = 0.99). Longer periods of reperfusion were associated with increasing pathologic grade.BER frequency and amplitude are very sensitive to ischemia and their changes occur well before histopathologic changes. The variation in electrical activity of the small bowel during ischemia and reperfusion is a dynamic process that reflects the metabolic state of the smooth muscle. If electrical activity of the bowel is to be used for assessment of viability, continuous recordings more accurately reflect the metabolic state of the smooth muscle.

The long acting somatostatin analogue octreotide acetate has been effective in the treatment of early dumping syndrome. We hypothesized that this may be related to its effects on inhibiting gastric emptying and delaying intestinal transit. To study the effect of octreotide acetate on intestinal motility in patients we carried out a randomized, double-blinded study using a subcutaneous injection of either octreotide acetate (100 micrograms) or placebo given 20 min prior to ingestion of a high carbohydrate "dumping" meal in six patients with known severe dumping syndrome. Prior to each study a multilumen polyethylene tube was inserted into the efferent limb to study small intestinal contractions using low compliance pneumo-hydraulic water-perfused manometry. Octreotide acetate prevented dumping symptoms in all six patients and induced the appearance of migrating myoelectric complexes (MMC) characteristic of interdigestive motility. After ingestion of the dumping meal the postprandial "fed" motility pattern lasted for 141 +/- 9 min while after octreotide acetate the fed motility lasted for 29 +/- 5 min (P less than 0.03). The vigor of the fed motility pattern as measured by the motility index (MI = loge (sum of amplitudes X No. of contractions + 1] was lower after octreotide acetate than after placebo (15.1 +/- 0.1 vs 13.4 +/- 0.2, P less than 0.03). The induction of fasting MMC motility pattern and reduction in the duration and vigor of fed motility may explain the symptomatic relief these patients obtained with octreotide acetate. It is not known whether the induction of the MMC is a direct effect of octreotide acetate or secondary to the concomitant inhibition of peptide release (neurotensin, insulin, glucagon, pancreatic polypeptide) that has been demonstrated in earlier studies.

Introduction. Appropriate patient selection is crucial to the success of bariatric surgery (BaS). The objective of this study was to identify risk factors of increased postoperative mortality in patients undergoing BaS on a national level. Methods. BaS patients ≥18 years old in the United States were identified from the 2001 Nationwide Inpatient Sample (NIS). The effect of gender, age, insurance status, and need for reoperation on postoperative mortality was examined using multivariate logistic regression accounting for the NIS stratified sampling design and using comorbidity adjustments appropriate for index hospitalization data. Results. Analysis of 7,452,727 discharges identified 10,503 bariatric surgical patients meeting inclusion criteria. Estimates were generalizable to a national cohort of 52,098 patients with age 41 ± 10 years (mean ± SE), 84% women, length of stay (LOS) 3.9 ± 0.2 days, and overall mortality of 4 per 1000 BaS patients. Risk factors for postoperative in-hospital mortality are shown (Table). Mean LOS of those who died was 17.6 ± 3.7 days. Conclusion. Based on national data, risk factors for increased postoperative mortality in BaS patients include male gender, age > 39 years, Medicaid insured, and need for reoperation. These data can assist in optimizing BaS patient selection. ∗ . % of BaS population Odds ratio for death ∗ 95% Confidence interval ∗ P value ∗ Female 84 (ref) (ref) Male 16 2.1 1.1–4.3 0.04 Age 18–39 46 (ref) (ref) Age 40–49 32 2.6 1.1–6.5 0.04 Age 50–59 19 4.3 1.7–11 0.002 Private Insurance 83 (ref) (ref) Medicaid 4.7 3.9 1.2–13 0.03 No reoperation † 99 (ref) (ref) Reoperation 1 22 5.4–88 0.0001 ∗ Adjusted for factors in table plus race, region and comorbidities; † Reoperation during original admission; ref = referent group