What is the management of small bowel obstruction?

Management of Small Bowel Obstruction

The management of small bowel obstruction (SBO) should begin with non-operative treatment including bowel decompression, water-soluble contrast agents, and fluid resuscitation, as this approach is safe and effective in approximately 70-90% of cases, while reserving surgical intervention for cases with signs of peritonitis, strangulation, or failed non-operative management. 1, 2

Initial Assessment and Diagnosis

• Physical examination should focus on identifying abdominal distension (positive likelihood ratio of 16.8), abnormal bowel sounds, and examination of all hernia orifices 3
• Laboratory tests should include complete blood count, CRP, lactate, electrolytes, BUN/creatinine, and coagulation profile to identify signs of ischemia or peritonitis 3, 2
• CT scan is the preferred imaging modality with high sensitivity and specificity for diagnosing SBO, identifying location, grade, and potential causes 3, 2
• Plain abdominal radiographs have limited diagnostic value with only 60-70% sensitivity 3, 2
• Signs of ischemia on CT include abnormal bowel wall enhancement, intramural hyperdensity, bowel wall thickening, mesenteric edema, pneumatosis, or mesenteric venous gas 4

Non-Operative Management

• Non-operative management is the initial approach for most SBO cases without signs of peritonitis, strangulation, or ischemia 1, 3
• Key components include:
  • Nil per os (NPO) status 3, 2
  • Nasogastric tube decompression for bowel decompression 3, 2
  • Intravenous crystalloid fluid resuscitation to correct dehydration 4, 3
  • Electrolyte monitoring and correction 3, 2
  • Foley catheter insertion to monitor urine output 4, 3
• Water-soluble contrast agents (e.g., Gastrografin) serve both diagnostic and therapeutic purposes 1, 3
  • Contrast reaching the colon within 4-24 hours predicts successful non-operative management 3, 5
  • Patients passing contrast to the colon within 5 hours have a 90% rate of resolution 5

Indications for Surgical Intervention

• Immediate surgical intervention is required for: 4, 3, 2
  • Signs of peritonitis
  • Evidence of strangulation or bowel ischemia
  • Closed-loop obstruction on imaging
  • Free fluid on imaging
  • Hypotension suggesting bowel compromise
• Surgery is also indicated when non-operative management fails after 72 hours 3, 2
• Laparotomy is generally preferred in patients with signs of ischemia or hypotension for better visualization and faster bowel assessment 4

Special Considerations for SBO in Virgin Abdomen (SBO-VA)

• Recent studies suggest a high incidence of adhesions even in patients with no prior abdominal surgery (virgin abdomen) 1
• Non-operative management has been found successful in many SBO-VA cases 1
• The use of water-soluble contrast agents significantly improves success rates of non-operative management in SBO-VA 1

Potential Complications and Monitoring

• Monitor for common complications: 3, 2
  • Dehydration with kidney injury
  • Electrolyte disturbances
  • Malnutrition
  • Aspiration pneumonia
• Nasogastric tube placement is associated with increased risk of pneumonia and respiratory failure 6
• Recurrence rates after initial operative management in SBO-VA range between 1-10% 1

Common Pitfalls to Avoid

• Delaying surgical intervention in patients with signs of peritonitis, strangulation, or ischemia significantly increases morbidity and mortality 4, 2
• Failing to adequately resuscitate before surgery can worsen outcomes 4
• Overlooking the need for damage control surgery in unstable patients with extensive bowel compromise 4
• Prolonged nasogastric decompression in patients without active emesis may increase complications and length of stay 6

Surgical Technique

• Laparotomy remains the surgical approach of choice in most SBO cases 1
• Laparoscopic approach may be considered in select stable patients, though conversion rates can be high 1
• The use of adhesion barriers can reduce recurrence rates in SBO caused by adhesions 1