What is the assessment and management plan for a patient with small bowel obstruction?

Assessment and Management of Small Bowel Obstruction

The cornerstone of small bowel obstruction (SBO) management is initial non-operative treatment with nasogastric decompression, IV fluids, and supportive care for 72 hours, unless there are signs of peritonitis, strangulation, or bowel ischemia requiring immediate surgical intervention. 1, 2

Assessment

Clinical Evaluation

• Thorough evaluation should focus on identifying signs of peritonitis, strangulation, or ischemia, which would require emergency surgical intervention 2, 3
• Physical examination should include assessment of abdominal distension, abnormal bowel sounds, and examination of all hernial orifices 3
• In 90% of cases, small bowel obstruction is caused by adhesions, hernias, and neoplasms 1
• Previous abdominal surgery history has 85% sensitivity and 78% specificity for predicting adhesive small bowel obstruction 1

Laboratory Tests

• Complete blood count, C-reactive protein, lactate, electrolytes, BUN/creatinine, and coagulation profile should be ordered 2, 3
• Elevated CRP, leukocytosis with left shift, and elevated lactate may indicate peritonitis or intestinal ischemia requiring urgent surgical intervention 2, 3

Imaging

• CT scan with intravenous contrast is the preferred imaging technique with superior diagnostic accuracy (>90%) compared to conventional radiography (50-60% sensitivity) 2, 3
• CT can identify the location, degree of obstruction, potential causes, and complications like ischemia or perforation 3, 4
• Plain abdominal radiography has limited diagnostic value with sensitivity of only 60-70% 1, 3

Management Plan

Non-Operative Management

• Non-operative management is effective in approximately 70-90% of patients with adhesive small bowel obstruction 1, 2
• Key components include:
  • Nil per os (NPO) status 1, 2
  • Nasogastric tube decompression 1, 2
  • Intravenous fluid resuscitation with crystalloids 2, 4
  • Electrolyte monitoring and correction 2, 3
  • Foley catheter insertion to monitor urine output 2, 4
  • Analgesia for pain control 2
• Duration of non-operative management should generally not exceed 72 hours if no improvement is observed 1, 3

Water-Soluble Contrast Agents

• Water-soluble contrast agents (e.g., Gastrografin) have both diagnostic and therapeutic value 2, 3
• If contrast reaches the colon within 4-24 hours, this predicts successful non-operative management with 96% sensitivity and 98% specificity 1, 2
• Administration of water-soluble contrast correlates with a significant reduction in the need for surgery 3, 5

Indications for Surgical Intervention

• Immediate surgical intervention is required for: 1, 2, 3
  • Signs of peritonitis
  • Suspected strangulation or intestinal ischemia
  • Closed-loop obstruction on imaging
  • Failure of non-operative management after 72 hours
  • Hypotension in the setting of SBO 4
• Laparotomy has traditionally been the surgical approach of choice for SBO 1, 3
• Laparoscopy may be considered in selected stable patients, though conversion rates can be high 1, 3

Special Considerations

Virgin Abdomen SBO

• SBO can occur in patients without previous abdominal surgery (virgin abdomen) 1, 3
• Causes in virgin abdomen include malignancy, Meckel's diverticulum, gallstone ileus, internal herniation, and intussusception 1
• Non-operative management has been found successful in many SBO cases with virgin abdomen 1
• The use of water-soluble contrast agents significantly improves success rates of non-operative management in SBO with virgin abdomen 1

Potential Complications

• Common complications include dehydration with renal injury, electrolyte disturbances, malnutrition, and aspiration pneumonia 1, 2
• Development of pneumonia and respiratory failure has been significantly associated with nasogastric tube placement in some studies 6
• Recurrence of intestinal obstruction is possible after non-operative management (12% within 1 year, increasing to 20% after 5 years) 2, 3

Pitfalls to Avoid

• Delaying surgical intervention in patients with signs of peritonitis, strangulation, or ischemia 2, 4
• Prolonging non-operative management beyond 72 hours in patients without clinical improvement 1, 3
• Using prokinetic agents like metoclopramide in complete bowel obstruction (contraindicated) 7
• Failing to adequately resuscitate hypotensive patients before surgery 4