What is the initial order set for a patient with a nasogastric tube (NGT) due to a small bowel obstruction (SBO)?

Initial Order Set for Small Bowel Obstruction with Nasogastric Tube

For a patient with an NGT placed for small bowel obstruction, the initial order set should include: NPO status, NGT to low intermittent suction, aggressive IV crystalloid resuscitation, Foley catheter placement for urine output monitoring, serial electrolyte monitoring with replacement, CT abdomen/pelvis with IV contrast if not already obtained, and serial abdominal exams every 4 hours to detect peritonitis or clinical deterioration. 1, 2

Core Management Components

NPO and Decompression

• Maintain strict NPO (nil per os) status as the cornerstone of non-operative management 1
• NGT to low intermittent suction for gastric decompression to reduce vomiting risk, prevent aspiration, and improve respiratory status 1, 2
• The NGT reduces intragastric pressure and gastric content volume, lowering the likelihood of emesis and pulmonary aspiration 1

Fluid Resuscitation and Monitoring

• Aggressive IV crystalloid resuscitation is essential as SBO patients are often significantly dehydrated and may be hypotensive 2
• Insert Foley catheter to monitor urine output as a direct marker of adequate resuscitation 2
• Target adequate urine output (typically >0.5 mL/kg/hr) to ensure end-organ perfusion 2

Laboratory Monitoring

• Serial electrolyte panels with aggressive correction of disturbances, particularly potassium, sodium, and chloride 1
• Common complications include dehydration with kidney injury and electrolyte abnormalities 1
• Monitor renal function given risk of acute kidney injury from dehydration 1

Clinical Assessment

• Serial abdominal examinations every 4 hours to detect signs of peritonitis, strangulation, or bowel ischemia 1, 3
• Any development of peritonitis, hemodynamic instability, or persistent severe pain despite decompression mandates immediate surgical consultation 1, 4

Imaging and Diagnostic Workup

CT Scan Protocol

• CT abdomen/pelvis with IV contrast is the preferred imaging modality with >90% diagnostic accuracy for SBO 2
• CT can identify critical complications including bowel ischemia, perforation, closed loop obstruction, and free fluid 2
• High-risk CT findings requiring immediate surgery include: abnormal bowel wall enhancement, intramural hyperdensity, bowel wall thickening, mesenteric edema, pneumatosis, mesenteric venous gas, free fluid, or closed loop obstruction 2

Water-Soluble Contrast Administration

• Consider administering 80-100 mL of water-soluble contrast (Gastrografin/Gastroview) via NGT after initial resuscitation if no immediate surgical indications exist 3, 4, 5
• Obtain abdominal plain films at 4,8,12, and 24 hours after contrast administration 3
• If contrast reaches the colon within 24 hours, this predicts successful non-operative resolution 3, 5
• Contrast reaching colon within 5 hours correlates with 90% resolution rate 3
• Water-soluble contrast has both diagnostic and therapeutic value, reducing need for surgery, time to resolution, and hospital stay 5

Surgical Decision-Making

Immediate Surgical Indications

• Proceed directly to operating room without delay if any of the following are present: 1, 2, 4
  • Signs of peritonitis on exam
  • Evidence of bowel strangulation or ischemia
  • Hemodynamic instability/hypotension suggesting bowel compromise
  • CT findings of ischemia, perforation, or closed loop obstruction
  • Free fluid on imaging

Timing of Surgery After Conservative Management

• Non-operative management can be safely attempted for up to 72 hours in patients without the above contraindications 1, 5
• If contrast does not reach colon within 24 hours, operative intervention should be performed 3
• After 72 hours of non-operative management without resolution, surgery is recommended 1, 5
• Delays beyond 72 hours significantly increase morbidity and mortality 1

Additional Supportive Measures

Nutritional Support

• Provide nutritional support as needed during the non-operative management period 1
• Consider TPN if prolonged NPO status is anticipated beyond 5-7 days

Aspiration Prevention

• Keep head of bed elevated 30-45 degrees to prevent aspiration 1
• Ensure NGT is functioning properly with adequate drainage

Prokinetic Agents

• Metoclopramide 10 mg IV may be considered to facilitate bowel function, though evidence specific to SBO is limited 6
• Administer slowly over 1-2 minutes IV 6

Critical Pitfalls to Avoid

• Never delay surgical intervention in patients with signs of peritonitis, strangulation, or ischemia - this significantly increases morbidity and mortality 1, 2
• Do not attempt prolonged non-operative management beyond 72 hours without clear evidence of clinical improvement 1, 5
• Avoid inadequate resuscitation before surgery as this worsens outcomes 2
• Do not overlook the need for damage control surgery in unstable patients with extensive bowel compromise 2
• Be aware that NGT use is associated with longer hospital stays and may indicate more severe disease, though it remains standard practice for decompression 7