What is the management of small bowel obstruction?

Management of Small Bowel Obstruction

Initial management of small bowel obstruction (SBO) should be conservative with analgesia, intravenous fluids, nutritional support, and nasogastric aspiration unless there is suspicion of strangulation requiring emergency surgery. 1

Initial Assessment and Diagnosis

• The evaluation should focus on identifying signs of peritonitis, strangulation, or ischemia, which would require emergency surgical intervention 1, 2
• Physical examination should include assessment of abdominal distension (positive likelihood ratio of 16.8), abnormal bowel sounds, and examination of all hernial orifices 1, 2
• Laboratory tests should include complete blood count, C-reactive protein, lactate, electrolytes, BUN/creatinine, and coagulation profile 1
• Elevated C-reactive protein, leukocytosis with left shift, and elevated lactate may indicate peritonitis or intestinal ischemia requiring urgent surgical intervention 1, 2
• CT scan with intravenous contrast is the preferred imaging technique with superior diagnostic accuracy (>90%) compared to conventional radiography (50-60% sensitivity) 1, 3

Non-Operative Management

• Non-operative management is effective in approximately 70-90% of patients with intestinal obstruction due to adhesions 1, 3
• Key components include:
  • Nil per os status (NPO) 1, 3
  • Nasogastric tube decompression for patients with significant distension and vomiting 1, 4
  • Intravenous fluid resuscitation with crystalloids 1, 3
  • Electrolyte monitoring and correction 1
  • Foley catheter insertion 1
  • Analgesia for pain control 1
• Water-soluble contrast agents (e.g., Gastrografin) have both diagnostic and therapeutic value 1, 5
• If contrast reaches the colon within 4-24 hours, this predicts successful non-operative management with 90% resolution rate when passing within 5 hours 1, 5

Indications for Surgical Intervention

• Immediate surgical intervention is required for:
  • Signs of peritonitis 6, 1
  • Suspected strangulation or intestinal ischemia 6, 1
  • Closed-loop obstruction on imaging 1, 3
  • Failure of non-operative management after 72 hours 1, 3
  • Hypotension in the setting of SBO 1
• Laparotomy has traditionally been the surgical approach of choice for SBO, but laparoscopy may be considered in selected patients with simple SBO 6, 1
• Hypotensive patients generally require laparotomy due to better visualization and faster bowel assessment 1

Predictors of Need for Surgery

• On multivariate analysis, independent predictors of the need for operative exploration include:
  • Free intraperitoneal fluid on CT (OR 3.80) 7
  • Mesenteric edema (OR 3.59) 7
  • Lack of the "small bowel feces sign" (OR 0.19) 7
  • History of vomiting (OR 4.67) 7
• The combination of these four factors has a sensitivity of 96% and a positive predictive value of 90% for requiring exploration 7

Potential Complications and Pitfalls

• Common complications include dehydration with renal injury, electrolyte disturbances, malnutrition, and aspiration pneumonia 1, 3
• Avoid delaying surgical intervention in patients with signs of peritonitis, strangulation, or ischemia 1
• Water-soluble contrast agents may further dehydrate patients due to their higher osmolarity, shifting fluids into the bowel lumen 1
• Recurrence of intestinal obstruction is possible after non-operative management (12% within 1 year, increasing to 20% after 5 years) 1, 3
• Development of pneumonia and respiratory failure is significantly associated with nasogastric tube placement, so tubes should be used selectively in patients with significant distension and vomiting 8

Special Considerations

• Younger patients have a higher lifetime risk for recurrent ASBO and might benefit from application of adhesion barriers as both primary and secondary prevention 6
• For malignant bowel obstruction, surgery after CT scan is the primary treatment option for patients with longer life expectancy 1
• For patients with advanced disease or poor condition, medical management may include pharmacologic measures, parenteral fluids, endoscopic management, and enteral tube drainage 1
• Recent evidence suggests that some stable patients with SBO may be managed in hospital-at-home settings after initial stabilization in the hospital, combining virtual care with in-home services 9