ADHESIVE small bowel obstruction

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Leslie Kobayashi Trauma Conference 2013. ADHESIVE small bowel obstruction. Overview. Background Pathophysiology/Etiology Diagnosis Treatment Outcomes. Small bowel obstruction (SBO). Mechanical obstruction of the small bowel preventing free passage of intraluminal material May be due to: - PowerPoint PPT Presentation

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ADHESIVE small bowel obstructionLeslie KobayashiTrauma Conference 2013OverviewBackground

Pathophysiology/Etiology

Diagnosis

Treatment

OutcomesSmall bowel obstruction (SBO)Mechanical obstruction of the small bowel preventing free passage of intraluminal materialMay be due to:Bowel wall inflammation, edema or tumorIntraluminal obstruction (bezoar, gallstone, foreign body)Extrinsic compression (adhesion, hernia, tumor, volvulus)BackgroundObstruction is the most common small bowel pathology requiring surgical consultation

Accounts for 20% of acute surgical admissions

Costs $800 million annually

BackgroundMost common causes of SBO

Adhesive 60-75%Malignancies 9-11%Hernias 8-18%IBD 5%

SBO in the virgin abdomenHistoricallyPrimary causes: hernia and volvulus

CurrentlyPrimary causes: malignancy, IBD

All cases of SBO in a virgin abdomen should be taken for operative exploration due to high failure rate of NOM and concern for malignancyAdhesive SBO

PathophysiologyAdhesions are fibrous bands of connective tissue that form in response to trauma, surgical manipulation, or inflammationCapillaries & Migration of FibroblastsPeritoneal DamageBleedingInflammationStable Fibrin matrixFibrinogenAdhesionBarmparas et al, J Gastrointest Surg 2010PathophysiologyPostmortem studyMinor procedure: 51% had adhesionsMajor procedure: 72% had adhesionsMultiple operations: 93% had adhesions

93% of 210 patients with abdominal procedures, had intra-abdominal adhesions at re-laparotomy.Weibel MA. Am J Surg 1973Menzies D. Ann R Coll Surg Engl 1990

Risk factors for SBOAgeComorbid conditionsPrior surgeryStepwise increase with number of prior proceduresSurgical techniqueOpen technique associated with significantly higher rates of SBORisk increased 2-8xsSurgeryTechniqueTotal # of patientsAdhesion-related readmissionAppendectomyOpenLap.266,6954,4451.4%1.3%CholecystectomyOpenLap.1417,1037.1%0.2%ColectomyOpenLap.121,0589309.5%4.3%Ileal pouch-anal anastomosisOpen5,26819.3%Laparotomy for TraumaOpen1,9132.5%Gynecological proceduresOpenLap.24,99877317.1%0%Procedure related riskBarmparas et al, J Gastrointest Surg 201011Trends over time?risk of SBO with laparoscopy compared to openLaparoscopy rate over timeHas this resulted in rate of SBO?No

Scott, et al Am J Surg 2012 and Angenete, et al Arch Surg 2012

EtiologyOverall incidence of SBO 4.6%

Top operations leading to SBO

Appendectomy 14-30%Colorectal 21-34%Gynecological surgery 12-28%

Diagnosis

Diagnosis: Clinical presentation

Anorexia, nausea, vomiting, obstipation (90%), constipation (80%), abdominal pain

Abdominal distension, high pitched bowel sounds, tympany, TTP, feculant NGT output/vomitus

Hypocholoremic, hypokalemic metabolic alkalosisDiagnosis: Radiology findingsPlain films

Benefits: rapid, repeatable, no contrast required, patient does not have to be supine for prolonged time period, can be done at bedside

Diagnosis: Radiology findingsFindings:

Distended loops of bowelAir-fluid levelsStep laddering of bowelLack of air in colon, rectumDiagnosis: Radiology findingsCT scans

Benefits: high sensitivity and specificity (90%), gives information on intra and extraluminal pathology, highly sensitive for free air/fluid, can identify transition zones, hernias, and bowel ischemiaDiagnosis: Radiology findingsFindings:

Dilated bowelTransition zone from dilated to collapsedPassage of contrast material (partial) or not (complete)Bezoars, masses

Treatment

TreatmentInitial management of all patients should include:

NGT decompressionJudicious fluid resuscitationCorrection of electrolyte imbalancesFoley catheter and close monitoring or UOP+/- central venous and/or arterial cathetersTreatmentMajority of cases (60-82%) can be treated conservatively with non-operative management (NOM)

Three indications for Early Operative Management (EOM):1: PerforationAny patient with peritonitis or free air-indicating perforation should go straight to OR

TreatmentYesOR2: IschemiaAny patients with concerning signs/symptoms for gangrenous or ischemic bowel should also go to the OR ASAP

Signs of bowel ischemiaClinical: sensitivity 40-50%

HypotensionTachycardiaFever or leukocytosis, Lactic acidosisSIRS responseDeterioration in exam

1983

Physical signsStrangulated(N=21)SensitivitySpecificityPPVTemp (F)99 0.9247036Pulse104 23524339No bowel sounds5/20258350Peritonitis6/21299786Clinical symptoms, base deficit, leukocytosis, blood glucose, and SIRS were assessedSIRS and base deficit were independently associated with gangrenous bowelSensitivity: 92%, Specificity: 96%PPV: 92%, NPV: 96%

2004

Signs of bowel ischemiaPlain filmsBowel wall edema, portal venous gas

CT: sensitivity 85-90%Thickened bowel wall, target sign, mesenteric stranding, congestion, ascites, pneumatosis, portal venous gas, decreased bowel wall enhancementTreatment3: High grade, or closed loop SBOPatients with high grade SBO, or those with closed loop obstruction should be strongly considered for early operative management

Signs of high grade SBO

> 25mmAir-fluid levels of differential heightin the same loopAir fluid width of25 mm or moreAccuracy of plain X-ray to diagnose a high grade SBOSensitivity 66-75%

Results of this technique are:Equivocal in about 20%30%Normal, nonspecific, or misleading in 10%20%Maglinte AJ, AJR Am J Roentgenol 1997Signs of high grade SBOSensitivity 80-93%

Contrast does not pass transition zone

Colon with little gas or fluid

Fecalization of small bowel

Diagnosis: Radiology findingsEAST Guidelines 2012

Level 1 recommendation for CT scans in SBO as they can provide incremental increase in information compared to plain films in differentiating grade, severity and etiology that may lead to changes in managementTreatmentNoClosed loop or high grade SBO?Yes-ORSummary: treatmentThree indications for early operative management:

PerforationIschemiaClosed loop or high grade obstruction

All others can be considered for NOMTreatmentNoClosed loop or high grade SBO?Yes-ORNo-obsPrinciples of NOMBowel rest, NGT decompression, fluid resuscitation

Serial abdominal exams and blood tests, consider serial abdominal films

Explore if deterioration in clinical exam, or new e/o ischemia or perforation

Keep in mindNOMDelay to OR is associated with:

Longer LOSIncreased incidence of bowel necrosis and need for bowel resectionIncreased mortalityIncreased morbidity

NOMGiven risks of delay to surgery:

How long should NOM trial last?Studies suggest 48hrs although can be longer in pSBO

NIS data suggest delay of 4d associated with 64% increase in mortality and increased LOSSchraufnagel et al, J Trauma 2013Are there any decision making aids?

NOMEAST Guidelines 2012

Level 2 recommendation

Consider water soluble contrast administration for prognosis and/or treatment in patients who fail to improve within 48hrsWater soluble contrastHyperosmolar radiopaque agent

Potential aid in prognosisPassage of contrast into LB may predict successful NOMFailure of progression predicts need for OR

Theoretically decreases bowel wall edema and may promote resolution of SBO

Br J Surg. 2010 Apr;97(4):470-8.

Water-Soluble Contrast (WSCA) Diagnostic and Therapeutic role

50100ml Gastrografin or 40ml Urografin administered orallyAbdominal plain radiographs after 4 h, 8 h or 24 h to follow contrast through the GI-tract

Br J Surg. 2010 Apr;97(4):470-8.

Water-Soluble Contrast (WSCA) Diagnostic and Therapeutic role

Meta-analysis of 14 prospective randomized controled studiesIf the contrast reaches the colon within 424 h, obstruction will resolve without operation in 99% of patients.

Br J Surg. 2010 Apr;97(4):470-8.

Water-Soluble Contrast (WSCA) Diagnostic and Therapeutic role

TimingnSensitivitySpecificityPPVNPV4-8h31295991008524h19699979997Effect of WSCA: Need for surgery

Effect of WSCA: Hospital length of stay

ConclusionWater-soluble contrast was effective in predicting the need for surgery in adhesive SBO (sensitivity 96%, specificity 98%)In addition, it reduced the need for operation and shortened hospital stay.

Br J Surg. 2010 Apr;97(4):470-8.

Water-Soluble Contrast (WSCA) Diagnostic and Therapeutic role

OutcomesOutcomesMortality 3-8%

Rates of recurrence 15-20% over 5 years

Rate of recurrence, # of recurrences, and time to recurrence significantly better in Operatively Managed compared to NOM groupOutcomesCalifornia OSHPD database 32,583 patients admitted in 1997 with SBO76% NOM24% OMOM group associated with Decreased mortality, decreased rate of readmissions, fewer readmissions, and longer time to readmissionFoster, et al JACS 2006SummaryAdhesions account for the majority of SBO in the US

Clinical exam and xrays reliably diagnose SBO

Early OM should be undertaken in patients with perforation, ischemia, and high grade or closed loop SBOSummary: When to operate?NOM successful in majority of patients, but shouldnt exceed 4dConsider use of Water-soluble contrast agents for both diagnostic and therapeutic purposesOperative management can decrease the rate and number of recurrences, and prolong the time to recurrence

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