What is the management for symptoms of small bowel obstruction (SBO)?

Management of Small Bowel Obstruction

Immediately assess for signs of peritonitis, strangulation, or ischemia—these require urgent surgical exploration within 12-24 hours, not conservative management. 1

Initial Assessment and Red Flags

The primary goal is identifying patients who need emergency surgery versus those suitable for conservative management. Look specifically for:

• Signs of peritonitis: diffuse tenderness, guarding, rebound, or abdominal rigidity—these mandate immediate surgery 1, 2
• Strangulation indicators: fever, hypotension, continuous (not colicky) abdominal pain, tachycardia, or localized severe tenderness 1, 3
• Laboratory red flags: elevated lactate, marked leukocytosis with left shift, or CRP >75 suggest ischemia, though normal values cannot exclude it 1

Physical examination has only 48% sensitivity for detecting strangulation, so do not rely on clinical assessment alone 1

Diagnostic Imaging

Order CT abdomen/pelvis with IV contrast immediately—this is the primary diagnostic tool with >90% accuracy for both diagnosis and surgical decision-making. 1, 2

CT findings requiring urgent surgery include:

• Closed-loop obstruction 2
• Abnormal bowel wall enhancement, pneumatosis, or mesenteric venous gas 2
• Bowel wall thickening with mesenteric edema 2
• Transition point with complete obstruction and no distal gas 1

Avoid plain radiographs as the primary diagnostic tool—they have only 60-70% sensitivity and provide no information about etiology or need for surgery. 1 They may prolong evaluation unnecessarily 1

Conservative Management Protocol

If no surgical red flags are present, initiate aggressive medical therapy:

• NPO (nil per os) status 4
• Nasogastric tube decompression for patients with significant distension and vomiting 4, 3
• IV crystalloid fluid resuscitation with aggressive correction of dehydration 4
• Electrolyte monitoring and correction, particularly potassium which is frequently low 1, 4
• Foley catheter to monitor urine output and assess hydration status 4
• Serial abdominal examinations to detect clinical deterioration 1

Do not give oral antihypertensives or oral contrast in suspected high-grade SBO due to aspiration risk. 2 Use IV antihypertensives like clevidipine or nicardipine if blood pressure control is needed 2

Water-Soluble Contrast Protocol

Administer water-soluble contrast agent (gastrografin) after initial CT if conservative management is planned:

• Prognostic value: If contrast reaches the colon on abdominal X-ray within 4-24 hours, this predicts 96% sensitivity and 98% specificity for successful non-operative resolution 1, 4
• Therapeutic value: May accelerate resolution of partial obstruction 1
• Failure indicator: Absence of contrast in colon at 24 hours strongly predicts need for surgery 1

This applies equally to virgin abdomen and post-surgical patients 1

Surgical Timing Decision

Proceed to surgery immediately if:

• Clinical peritonitis is present 2, 4
• CT shows closed-loop obstruction or bowel ischemia 2
• Complete obstruction without resolution after initial resuscitation 2

Proceed to surgery after 72 hours if:

• Conservative management fails to show improvement 4
• Water-soluble contrast does not reach colon by 24 hours 1
• Clinical deterioration occurs during observation 1

Critical pitfall: Do not delay surgery for "optimization" in patients with signs of bowel ischemia—mortality reaches 25% with delayed recognition of strangulation. 2 The median delay in one study was 2-4 days for patients with strangulation who were initially managed conservatively, resulting in worse outcomes 5

Surgical Approach

Laparotomy is preferred over laparoscopy in most SBO cases, particularly with hemodynamic instability or suspected ischemia 2 However, diagnostic laparoscopy within 12-24 hours is appropriate for stable patients with persistent pain and inconclusive findings 1

During exploration:

• Assess entire small bowel from ileocecal junction proximally 1
• Evaluate intestinal viability; resect if ischemia present 1
• Consider indocyanine green fluorescence angiography if available to assess bowel perfusion 1

Monitoring During Conservative Management

Monitor for complications including:

• Dehydration with acute kidney injury (check BUN/creatinine) 1, 4
• Electrolyte disturbances requiring correction 4
• Aspiration pneumonia risk 2
• Clinical deterioration suggesting failed conservative therapy 1

Conservative management is successful in 70-90% of partial SBO cases, but requires vigilant monitoring for the 10-30% who will need surgery 4, 3