What is the plan of care for a patient with a small bowel obstruction?

Small Bowel Obstruction Management

Begin immediate conservative management with IV crystalloid resuscitation, nasogastric decompression, bowel rest (NPO), and administration of 100 mL water-soluble contrast (Gastrografin) via NG tube for all patients without signs of peritonitis, strangulation, or ischemia—this approach successfully resolves 70-90% of cases and should continue for up to 72 hours before considering surgery. 1

Initial Assessment and Risk Stratification

Immediate Evaluation Priorities

• Focus on identifying signs requiring emergency surgery: peritonitis (involuntary guarding, abdominal rigidity, rebound tenderness), strangulation, or intestinal ischemia 2, 1
• Examine all hernial orifices during physical examination, as hernias account for 10% of SBO cases 2, 1
• Assess for specific high-risk CT findings: free intraperitoneal fluid (82% sensitive for ischemia), mesenteric edema (91% sensitive for ischemia), closed-loop obstruction, pneumatosis intestinalis, or portal venous gas 3

Laboratory Assessment

• Obtain complete blood count, C-reactive protein, lactate, electrolytes, BUN/creatinine, and coagulation profile 1
• Elevated lactate (>2.7 mmol/L), marked leukocytosis with left shift, and bandemia indicate possible intestinal ischemia requiring immediate surgery 4, 3

Imaging Strategy

• CT with IV and oral water-soluble contrast is the preferred diagnostic modality with high sensitivity and specificity for identifying location, degree, and cause of obstruction 1, 5
• MRI is a valid alternative in children and pregnant women (95% sensitivity, 100% specificity) 1
• Plain radiographs have limited value (60-70% sensitivity) and should not delay CT imaging 1

Conservative Management Protocol

Core Components (First 72 Hours)

• Nothing by mouth (NPO) 1
• Nasogastric tube decompression to reduce gastric distension and aspiration risk 1, 4
• IV crystalloid resuscitation with aggressive correction of electrolyte abnormalities and dehydration 1, 4
• IV antibiotics to prevent bacterial translocation from distended bowel 4

Water-Soluble Contrast Administration

• Administer 100 mL Gastrografin via NG tube after adequate gastric decompression 1
• This serves both diagnostic and therapeutic purposes, significantly reducing need for surgery, time to resolution, and length of stay 1
• If contrast reaches the colon within 4-24 hours, there is 90% likelihood of successful non-operative resolution 1
• Patients passing contrast within 5 hours have particularly high resolution rates 1

Monitoring During Conservative Management

• Reassess clinically every 4-6 hours for development of peritoneal signs, worsening pain, or hemodynamic instability 1
• A 72-hour period is considered safe for non-operative management before proceeding to surgery 1

Indications for Immediate Surgical Intervention

Absolute Indications (Operate Immediately)

• Signs of peritonitis: diffuse tenderness, involuntary guarding, abdominal rigidity, rebound tenderness 2, 1
• Free perforation with pneumoperitoneum and free fluid 1
• CT evidence of strangulation or closed-loop obstruction 1, 3
• Hemodynamic instability or severe sepsis/septic shock 1
• Pneumatosis intestinalis or portal venous gas 3

Relative Indications

• Failure of conservative management after 72 hours 1
• Clinical deterioration during observation: increasing pain, persistent vomiting, worsening distension, inability to pass flatus 1
• Combination of high-risk features: vomiting + absence of "small bowel feces sign" on CT + free intraperitoneal fluid + mesenteric edema (96% sensitivity, 90% positive predictive value for requiring surgery) 3

Surgical Approach Selection

Laparotomy (Standard Approach)

• Open laparotomy remains the surgical approach of choice in most SBO cases requiring surgery 1
• Mandatory for hemodynamically unstable patients, diffuse peritonitis, or very distended bowel loops 1

Laparoscopic Adhesiolysis (Select Cases)

• Consider only in hemodynamically stable patients with single adhesive band on CT, clear transition point, and minimal bowel distension 1
• Reduces morbidity, in-hospital mortality, and surgical infections compared to open surgery 1
• Critical pitfall: Risk of iatrogenic bowel injury is 3-17.6%, and all enterotomies must be identified intraoperatively 1
• Conversion rates can be high; bowel resection rates may be higher with laparoscopy (53.5% vs 43.4% open) 1

Damage Control Surgery

• For severe sepsis/septic shock: perform resection, staple intestinal ends, and temporary closure (laparostomy) 1

Special Populations and Considerations

Adhesive SBO (65% of Cases)

• Adhesions from prior surgery account for 55-75% of SBO cases 2, 4
• In young patients, use adhesion barriers (hyaluronate carboxymethylcellulose) during surgery to reduce recurrence from 4.5% to 2.0% at 24 months 1
• Recurrence after non-operative management: 12% at 1 year, 20% at 5 years 1

Virgin Abdomen (No Prior Surgery)

• Adhesions can occur from congenital bands or unrecognized prior inflammation 1
• Non-operative management with water-soluble contrast is appropriate and effective 1
• In young females, examine for ovarian masses, endometriosis, or pelvic inflammatory disease as potential causes 1

Malignant Bowel Obstruction

• For patients with years-to-months life expectancy, surgery is primary treatment after appropriate imaging 2, 1
• For advanced disease or poor condition, use medical management: opioids, anticholinergics (scopolamine, hyoscyamine, glycopyrrolate), corticosteroids (up to 60 mg/day dexamethasone), and antiemetics 2
• Octreotide is highly recommended early (150-300 mcg SC bid or continuous infusion) due to high efficacy and tolerability 2, 1
• Avoid prokinetic agents like metoclopramide in complete obstruction (may be beneficial in incomplete obstruction) 2
• Consider endoscopic stent placement or percutaneous gastrostomy for drainage 2

Inflammatory Bowel Disease

• Free perforation is absolute indication for emergency surgery 1
• Stenoses deserve trial of anti-inflammatory medications first 1
• Endoscopic balloon dilation has 89-92% technical success rate for primary intestinal or anastomotic strictures 1, 6
• Any colorectal stricture requires endoscopic biopsies to rule out malignancy 1

Critical Pitfalls to Avoid

• Do not delay CT imaging in favor of plain radiographs when SBO is suspected 1, 5
• Do not use bulk laxatives (psyllium) in significant bowel obstruction as they require adequate colonic motility and can worsen obstruction 7
• Avoid opioids and anticholinergics during conservative management as they slow intestinal motility and can precipitate complete obstruction 8
• Do not continue conservative management beyond 72 hours without surgical consultation if no improvement 1
• Recognize that very distended bowel loops are a contraindication to laparoscopy due to high risk of iatrogenic injury 1
• In post-bariatric surgery patients, maintain very low threshold for surgical evaluation as internal hernia requires exploratory laparoscopy within 12-24 hours 8

Outcomes and Prognosis

• Overall mortality is 10% but increases to 30% with bowel necrosis or perforation 4
• Conservative management successfully resolves 70-90% of adhesive SBO cases 1, 4
• Recurrence after operative management: 8% at 1 year, 16% at 5 years 1