What is the treatment for a patient with a small bowel obstruction?

Treatment of Small Bowel Obstruction

Begin immediate conservative management with NPO, nasogastric decompression, IV fluid resuscitation, and water-soluble contrast administration for all patients without signs of peritonitis, strangulation, or ischemia—this approach successfully resolves 70-90% of adhesive obstructions and should continue for up to 72 hours before considering surgery. 1, 2, 3

Initial Assessment and Risk Stratification

Your first priority is identifying patients who need emergency surgery versus those suitable for conservative management:

Immediate surgical indicators include:

• Signs of peritonitis (rebound tenderness, guarding, rigidity) 1, 2
• Clinical evidence of strangulation or ischemia (fever, hypotension, diffuse severe pain, peritoneal signs) 1
• Pneumoperitoneum with free fluid on imaging 1
• Closed-loop obstruction on CT 2, 4
• Hemodynamic instability despite resuscitation 1

Laboratory red flags suggesting complicated obstruction:

• Elevated lactate indicating ischemia 2, 3
• Marked leukocytosis with left shift 2, 5
• Elevated C-reactive protein 2, 6

Conservative Management Protocol

For patients without emergency surgical indications, implement this structured approach:

Core interventions (initiate immediately):

• Nothing by mouth (NPO) 1, 2, 3
• Nasogastric tube decompression for patients with significant distension and vomiting 1, 2, 7
• Aggressive IV crystalloid resuscitation to correct dehydration and electrolyte abnormalities 1, 2, 5
• Correct electrolyte disturbances, particularly potassium and sodium 2, 3
• IV antibiotics if signs of bacterial translocation or early sepsis 5

Water-soluble contrast protocol (critical component):

• Administer 100 mL of hyperosmolar iodinated contrast (diatrizoate meglumine/sodium) diluted in 50 mL water via NG tube or orally 1
• Obtain abdominal radiographs at 8 and 24 hours post-administration 1
• If contrast reaches the colon by 24 hours, surgery is rarely needed 1, 2
• This protocol significantly reduces need for surgery and shortens hospital stay 1, 2
• Caution: Water-soluble contrast can worsen dehydration due to high osmolarity—ensure adequate IV hydration 3

Long intestinal tubes vs. nasogastric tubes:

• Long trilumen naso-intestinal tubes are more effective than standard NG tubes but require endoscopic insertion 1, 2
• Reserve for refractory cases or when expertise available 1

Imaging Strategy

CT abdomen/pelvis with IV contrast is the diagnostic gold standard:

• Sensitivity and specificity exceed 90% for detecting SBO 1, 2, 4
• Do not use oral contrast in suspected high-grade obstruction—it delays diagnosis, increases aspiration risk, and obscures bowel wall enhancement patterns that indicate ischemia 1
• Nonopacified fluid in dilated bowel provides adequate intrinsic contrast 1
• CT identifies location, degree, etiology, and complications (ischemia, closed-loop, volvulus) 1, 2, 4

CT findings indicating ischemia (surgical emergency):

• Abnormal bowel wall enhancement (decreased or increased) 1
• Bowel wall thickening with mesenteric edema 1
• Pneumatosis intestinalis or mesenteric venous gas 1
• Ascites with intramural hyperdensity on noncontrast images 1

Timing of Surgical Intervention

The 72-hour rule:

• Most authorities consider 72 hours of conservative management safe and appropriate before surgery 1, 2, 3
• Operate earlier if clinical deterioration occurs (worsening pain, peritoneal signs, rising lactate, hemodynamic instability) 2, 5
• Mortality increases from 10% to 30% when bowel necrosis or perforation develops 5

Surgical indications after failed conservative management:

• No clinical improvement after 72 hours of appropriate conservative therapy 1, 2, 3
• Water-soluble contrast fails to reach colon by 24 hours 1, 2
• Progressive abdominal distension despite decompression 7
• Development of peritoneal signs during observation 1, 2

Surgical Approach Selection

Laparotomy remains the standard approach for most cases 2, but laparoscopic adhesiolysis may be considered in highly selected patients:

Ideal candidates for laparoscopic approach:

• Hemodynamically stable without diffuse peritonitis 1, 2
• Single adhesive band identified on CT with clear transition point 2
• Minimal bowel distension 2
• Available expertise in laparoscopic techniques 1

Contraindications to laparoscopy:

• Very distended bowel loops (high risk of iatrogenic injury) 2
• Hemodynamic instability 1
• Diffuse peritonitis or free perforation 1

Benefits of laparoscopy when appropriate:

• Reduced morbidity and surgical site infections 2
• Shorter hospital stay 1
• Lower in-hospital mortality 2

Critical pitfall: Iatrogenic bowel injury occurs in 3-17.6% of laparoscopic cases—all enterotomies must be identified intraoperatively to avoid missed perforations 2

Special Considerations

Adhesion prevention in young patients:

• Use hyaluronate carboxymethylcellulose barriers during surgery to reduce recurrence from 4.5% to 2.0% at 24 months 2, 4
• Young patients have highest lifetime risk for recurrent adhesive obstruction 2

Recurrence rates after conservative management:

• 12% readmission within 1 year 1, 3, 4
• 20% readmission after 5 years 1, 3, 4

Malignant bowel obstruction:

• Surgery is primary treatment for patients with years-to-months life expectancy after appropriate imaging 2, 3
• For advanced disease or poor performance status, use medical management: octreotide (highly effective early), opioids, anticholinergics, corticosteroids, antiemetics 2, 4

Inflammatory bowel disease (Crohn's strictures):

• Trial medical therapy first for inflammatory strictures 1, 2
• Endoscopic balloon dilation successful in 89-92% of accessible short strictures 2
• Surgery mandatory for symptomatic fibrotic strictures not amenable to dilation 1, 2
• Always biopsy colorectal strictures to exclude malignancy 1, 2

Common Pitfalls to Avoid

Do not use metoclopramide or other prokinetic antiemetics in complete obstruction—they increase motility against a fixed obstruction and can worsen ischemia, though they may benefit partial obstruction 3, 8

Monitor for complications during conservative management:

• Dehydration with acute kidney injury 2, 3, 4
• Electrolyte disturbances (hypokalemia, hyponatremia) 2, 3, 4
• Aspiration pneumonia 2, 3, 4
• Malnutrition in prolonged cases 2, 4

Plain abdominal radiographs have limited value:

• Sensitivity only 50-70% 2, 3
• Cannot exclude diagnosis 7
• Use for water-soluble contrast follow-up only, not primary diagnosis 1, 3