M1520

CT Scan in the Diagnosis of Acute Appendicitis: Help or Hindrance?Akpofure Peter Ekeh, Benjamin Monson, Curtis Wozniak, Jennell Smith, Mary C.McCarthy, Alex Little

Objective The use of preoperative abdominal Computerized Tomography (CT) in the evalu-ation of presumed appendicitis has improved diagnostic accuracy and reduced negativeappendectomy rates. We sought to identify the effect of the increased use of CT on the timeto operative intervention and perforation rates at a single institution. Method Patients whohad appendectomies for presumed appendicitis between January 2000 and May 2006 wereidentified. Patients who had preoperative CT were recognized as was the type of CT techno-logy used at the time of presentation (single slice, 4-slice or 16-slice). The length of timebetween presentation to the emergency department and the operative procedure, and histo-pathology reports were reviewed. Results In the studied period, 1416 appendectomieswere performed for presumed appendicitis. Preoperative CT was performed in 56% ofpatients(30.2% in the single-slice period, 55.8% in 4-slice period and 78.6% in16-sliceperiod.) The average time between presentation and commencement of surgery was increasedin patients who had preoperative CT - 12.2 ± 9.8 hours vs. 7.7 ± 6.3 hours in patientswithout preoperative CT. This was statistically significant(p < .001) The results were similarin the single slice, 4-Slice and 16-slice periods. There was also a statistically significantincrease in the perforation rate in patients with preoperative CT (16.4% vs. 6.0%; p < 0.01).Preoperative CT was noted to be an independent risk factor for perforation by multivariateanalysis - odds ratio of 3.16 (95% CI 2.09-4.77) Conclusion Preoperative CT improvespreoperative diagnostic accuracy for acute appendicitis but is associated with a delayed timeto surgery and an increase in the perforation rate. Its use should be more selectively appliedfor these reasons.

M1521

The Likely Cause of Postoperative “Feeding Intolerance” and Its PreventionGerald Moss

Hypothesis: “Feeding intolerance” results from localized proximal G-I distention caused bytotal inflow to the feeding site (feedings + secretions) exceeding peristaltic outflow. Vagalreflexes initiate a “downhill spiral” that paralyzes the already sluggish gut, leading to general-ized distention, poor respiratory mechanics, etc. Methods: We studied consecutive surgicalpatients (160 cholecystectomy, 17 colectomy, and 3 esophagectomy). All were immediatelyfed elemental diet @ ≥100 kcal/hour into the distal duodenum. Efficient aspiration 7 cmproximal to the feeding site removed all air and any excess liquid (confirmed by X-ray).Colectomy patients had contrast X-ray motility study. Serial analyses were conducted forserum amino acids and glucose; aspirate was assayed for removed foodstuff; hourly nitrogenbalances were determined. Cholecystectomy aspirate was replaced by IV fluids. Colectomypatients had degassed aspirate “refed” manually. Esophagectomy patients were “refed” auto-matically, in effect performing a “check for residual” every 30 seconds. Results: No adverseevents were attributable to the feeding-decompression regimens. Aspirate was free of feedingsolution within two hours; serum levels of amino acids had risen above basal; glucose was>150 mg/dl. Most (even non-diabetics) required supplemental insulin to maintain euglycemia.Requirement for insulin dependent diabetics rose markedly during those initial 24 hours.All except esophagectomy patients (still on respiratory support) tolerated their usual dietsby 24 hours after surgery without supplemental insulin. Every cholecystectomy patient(160:160) had a cathartic induced bowel movement, and was discharged within 24 hoursof surgery. One patient (1:160) died of a pulmonary embolus 29 days later. One patient(1:160) developed an abdominal infection. One patients (1:160) was re-admitted for percu-taneous aspiration of a sterile biloma. One patient (1:160) was re-admitted for a transientischemic attack. Normal motility was noted within hours of colectomy. Net absorption was>2,300 kcal the initial 24 hours. Contrast traversed secure anastomoses to exit in a bowelmovement within 48 hours, and all achieved positive protein balance within 2 - 24 hours.Four patients were discharged uneventfully 24 hours after colectomy. “Refed” patients hadonly 100-200 ml/day of aspirate discarded, containing <100 ml of elemental diet. Conclu-sions: “Feeding intolerance” appears to be triggered by G-I distention at the intestinal feedingsite. A regimen that titrates inflow to match peristaltic outflow prevents this complication,while permitting more rapid achievement of nutritional goals.

M1522

The Clinical Significance of Adult Intussusception Found By ComputedTomographyParissa Tabrizian, Scott Q. Nguyen, Alexander Greenstein, Uma Rajhbeharrysingh, PamelaA. Argiriadi, Meade Barlow, Tiffany E. Chao, Celia M. Divino

Objective: The finding of intestinal intussusception on radiographic imaging in adults remainsa challenging clinical dilemma. The clinical significance of this finding is unknown anddetermining cases requiring operative therapy is difficult. We present a series of cases ofadult intussusception (AI) found on computed tomography (CT) and examine the significantparameters that would guide the management of this condition. Methods: A retrospectivereview of records of adult patients found to have intussusception on CT at the MountSinai Medical Center from 2001-2007 was performed. Chi-Square and multivariable logisticregression analyses were used to identify factors associated with a true intussusception.Results: AI was found on CT scan in 80 patients (M=34, F=46) during the study period.The mean age was 45 years. Patients presented with obstructive symptoms in 41% andabdominal pain in 56%. On CT, the intussusceptions were enteroenteric in 87% enterocolicin 4%, and colocolic in 9%. Imaging demonstrated multiple intussusceptions in 6% andobstructive findings in 11% of patients. 53 patients were observed and all of these had nofurther associated clinical sequelae. 9 patients, found to have an incidental finding ofintussusception on CT scan underwent surgery with no intraoperative finding of true intussus-ception. 18 patients were explored based on CT findings, out of which 12 were found tohave a true intussusception. The operative specificity was 67%. A pathologic leadpoint wasidentified in 9 cases [Crohns enteritis (2), appendiceal mucinous cystadenoma (1), cecal

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fibroid tumor (1), carcinoid (2), and adenocarcinoma (3), idiopathic (3)]. All patientswith negative explorations recovered without complication. Factors associated with a trueintussusception on univariate analysis were gastrointestinal symptoms, obstruction onimaging studies, and involvement of the colon (p<0.05). Factors independently associatedwith a true intussusception on multivariate analysis were obstruction on imaging studiesand colonic involvement (p<0.05). Conclusion: The radiographic finding of AI remains aclinical dilemma. The majority of cases are incidental findings on CT and have no significantclinical sequelae. Factors such as gastrointestinal symptoms, obstruction on imaging studies,colonic involvement are clinically significant and mandate prompt surgical intervention.

M1523

Gastroesophageal Reflux Disease and Connective Tissue Disorders.Pathophysiology and Implications for TreatmentWarren J. Gasper, Piero Fisichella, Francesco Palazzo, Marco G. Patti

Background: It has been postulated that in patients with connective tissue disorders (CTD)and gastroesophageal reflux disease (GERD), esophageal function is routinely deteriorated,often with absence of peristalsis. This belief has led to the common recommendation ofavoiding antireflux surgery for fear of creating dysphagia. Hypothesis: a) in most patientswith CTD and GERD, esophageal function is preserved; b) only in patients with end-stagelung disease (ESLD) peristalsis is frequently absent; c) a tailored approach (total vs. partialfundoplication) allows control of reflux without a high incidence of postoperative dysphagia.Design: Retrospective review of a prospectively acquired database. Setting: University tertiarycare center. Patients: Forty-eight patients with CTD were evaluated by esophageal manometryand 24 hour pH monitoring (EFT). Twenty patients (Group A) had EFT because of foregutsymptoms and 28 patients with ESLD (Group B) had EFT as part of the lung transplantevaluation. Two hundred eighty-eight consecutive patients with GERD (Group C) served asa control group. Eight patients in Group B underwent a laparoscopic fundoplication (3patients, 360°; 5 patients, 240°). Results: Fundoplication resulted in control of reflux for 8patients in Group B. One patient developed post-operative dysphagia, which resolved withSavary dilatation. Conclusions: These data show that: a) peristalsis was preserved in mostpatients with CTD, similar to patients who had GERD without CTD; b) peristalsis was absentin a third of patients with CTD and ESLD; and c) a surgical approach tailored to theesophageal peristalsis achieved control of reflux without a high incidence of dysphagia.

*p<0.05, A vs. B; †p<0.05, A vs. C; ‡p<0.05, B vs. C

M1524

Association of Gastroesophageal Reflux and O2 Desaturation in Patients withGERD; a Novel Study of Simultaneous 24-Hour Impedance-pH andContinuous Pulse-OximetryRenato Salvador, Fernando A. Herbella, Attila Dubecz, Marek Polomsky, Thadeus Trus,Carolyn E. Jones, Daniel Raymond, Thomas J. Watson, Jeffrey H. Peters

Background: Respiratory symptoms are present in up to 50% of GERD patients and are theprimary or sole symptoms in 20-25%. The well described role of both reflex and refluxmechanisms, coupled with the lack of optimal diagnostic tests, make assessment of the roleof GERD in symptom causation a challenge. The aim of this study was to assess the associationof gastroesophageal reflux with O2 saturation in patients with and without respiratorysymptoms using combined simultaneous ambulatory monitoring systems. Methods: Thestudy population consisted of 11 patients with symptoms of GERD in which 443 refluxepisodes were detected by MII-pH study. Eight patients had primary respiratory symptoms(cough, wheezing, hoarseness), and 3 typical symptoms (heartburn and regurgitation). Allpatients underwent simultaneously timed 24 hr MII-pH and continuous O2 saturationmonitoring via ambulatory reflux and pulse-oximetry monitoring. Reflux events were definedby 24hr esophageal pH and/or impedance and O2 desaturation by one of 3 possible observa-tions; 1) O2 saturation <90%, 2) O2 saturation drop of 7%, and 3) any event 7% belowthe mean saturation over 24 hours. Proximal reflux was defined by pH <4 20cm above theLES or reflux in proximal 2 impedance channels. A reflux-desaturation association wasconsidered present if O2 desaturation occurred within 30 seconds prior to or 10 minutesafter a reflux event. Results: Three hundred thirty eight reflux events occurred in patientswith primary respiratory symptoms and 105 in those with typical GERD symptoms. Nearly60% of these 443 reflux events were associated with O2 desaturation. Markedly more eventswere associated with O2 desaturation in patients with respiratory symptoms (68%, 229/338) than in patients with typical reflux symptoms (25%, 26/105, p<0.01). The differencein reflux-desaturation association was even more profound when proximal reflux eventswere compared, occurring in 76% (130/171) of patients with respiratory symptoms vs 14%(8/56) of those with typical GERD symptoms (p<0.01). Conclusion: There is a remarkablyhigh prevalence of oxygen desaturation associated with esophageal acidification in patientswith primary respiratory symptoms. This novel observation adds to our understanding ofthe pathogenesis of GERD related respiratory symptoms and, given further study, may proveto be a useful diagnostic test in this difficult group of patients.

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