Should a patient with suspected small bowel obstruction (SBO) be evaluated in the emergency room (ER)?

Evaluation of Suspected Small Bowel Obstruction in the Emergency Room

Yes, patients with suspected small bowel obstruction (SBO) should be evaluated in the emergency room due to the potential for life-threatening complications including intestinal ischemia, necrosis, and perforation. 1, 2

Clinical Presentation Requiring Emergency Evaluation

• Concerning symptoms and signs:

  • Crampy central abdominal pain
  • Abdominal distension
  • Nausea and vomiting
  • Constipation
  • Abnormal bowel sounds
  • History of prior abdominal surgery (strongest risk factor) 1, 3

• Red flags requiring immediate attention:

  • Signs of strangulation: fever, hypotension, diffuse abdominal pain
  • Peritonitis
  • Elevated white blood cell count or lactic acid 1, 2

Emergency Department Diagnostic Approach

1. Initial imaging:

   • CT abdomen/pelvis without oral contrast is the preferred initial imaging modality with >90% diagnostic accuracy for high-grade SBO 1
   • Oral contrast is not required and may delay diagnosis or worsen obstruction 1
   • Plain radiographs have limited sensitivity (46.2%) and are non-diagnostic in 36% of cases 4

2. Additional diagnostic options:

   • Bedside ultrasound performed by emergency physicians has shown excellent sensitivity (91%) and specificity (84%) for detecting dilated bowel loops 4
   • Water-soluble contrast challenge can help differentiate partial from complete obstruction and predict need for surgery 1

Management Algorithm in the Emergency Room

1. Initial resuscitation:

   • IV fluid resuscitation
   • Analgesia
   • Nasogastric tube placement for patients with significant distension and vomiting 2

2. Surgical consultation:

   • Immediate surgical consultation for signs of:
     • Strangulation
     • Complete obstruction
     • Closed-loop obstruction
     • Ischemia
     • Peritonitis 1, 2

3. Decision for operative vs. non-operative management:

   • Indications for urgent surgery:

     • Signs of strangulation or ischemia on CT (abnormal bowel wall enhancement, pneumatosis)
     • Peritonitis
     • Complete high-grade obstruction
     • Closed-loop obstruction 1, 5

   • Candidates for initial non-operative management:

     • Partial obstruction without signs of complications
     • Stable vital signs
     • No peritonitis 2, 6

4. Timing of intervention:

   • Exploratory laparoscopy is recommended within 12-24 hours in stable patients with persistent abdominal pain and inconclusive initial workup 1
   • Delay in surgical intervention beyond 48 hours is associated with significantly increased mortality 7

Special Considerations

• Post-bariatric surgery patients:

  • Higher risk of internal hernias
  • Surgical exploration should start from the ileocecal junction and inspect all potential sites of internal hernia 1

• Low-grade or intermittent SBO:

  • May present more indolently with intermittent symptoms
  • Standard CT has lower sensitivity (48-50%) for low-grade obstructions
  • CT enterography or enteroclysis may be needed for diagnosis 1

Common Pitfalls to Avoid

• Delaying surgical consultation when signs of strangulation are present
• Relying solely on plain radiographs to exclude SBO
• Administering oral contrast without surgical consultation in complete obstruction
• Failing to recognize closed-loop obstruction, which requires urgent intervention
• Discharging patients with partial SBO without adequate follow-up plans 1, 2

The emergency evaluation of suspected SBO is critical as timely diagnosis and appropriate management significantly reduce morbidity and mortality associated with this potentially life-threatening condition.