What is the step‑by‑step evaluation and management of paralytic ileus in a critically ill patient?

Stepwise Evaluation and Management of Paralytic Ileus in Critically Ill Patients

In critically ill patients with paralytic ileus, immediately assess for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS), optimize sedation and analgesia, decompress the gastrointestinal tract, initiate prokinetic therapy with combination agents, and aggressively manage the underlying precipitants—particularly infection, electrolyte imbalances, and opioid exposure. 1, 2

Step 1: Initial Assessment and Risk Stratification

Measure Intra-Abdominal Pressure (IAP)

• Measure IAP via trans-bladder technique when any risk factor for IAH/ACS is present (bowel distension qualifies as a risk factor). 1
• IAH is defined as IAP ≥12 mmHg, and ACS is defined as IAP >20-25 mmHg with organ dysfunction. 1, 3
• Use protocolized IAP monitoring and management rather than sporadic measurements. 1
• IAH occurs in up to 20% of critically ill patients and can lead to cardiovascular, pulmonary, renal, hepatic, and neurological dysfunction. 3

Identify Precipitating Factors

• Infection: Present in 60-80% of critically ill patients with ileus—initiate empiric broad-spectrum antibiotics immediately if sepsis is suspected. 4
• Opioid exposure: The most modifiable cause—minimize or eliminate opioids as they directly impair intestinal motility. 1, 5
• Electrolyte imbalances: Correct hypokalemia, hypomagnesemia, and hypocalcemia. 6, 5
• Immobility: Early mobilization is critical to restore bowel function. 5
• Medications: Review and discontinue anticholinergics, antipsychotics, and other constipating agents. 7

Assess for Mechanical Obstruction

• Obtain plain abdominal radiography or CT scan to differentiate paralytic ileus from mechanical obstruction, bowel ischemia, or perforation. 8, 6
• Do NOT delay imaging if clinical deterioration occurs—bowel ischemia and perforation are surgical emergencies. 3

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Step 2: Non-Invasive Medical Management

Optimize Sedation and Analgesia

• Ensure adequate pain control while minimizing opioids—use multimodal analgesia with acetaminophen, NSAIDs (if not contraindicated), and regional techniques. 1
• Consider brief trials of neuromuscular blockade as a temporizing measure to reduce abdominal wall tension and IAP. 1

Gastrointestinal Decompression

• Place nasogastric tube for gastric decompression when the stomach is dilated. 1
• Place rectal tube for colonic decompression when the colon is dilated. 1
• This is particularly important when IAH is present, as decompression can reduce IAP and prevent progression to ACS. 1

Body Positioning

• Consider the potential contribution of body position to elevated IAP—avoid prolonged supine positioning if possible. 1

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Step 3: Pharmacologic Prokinetic Therapy

First-Line: Combination Prokinetic Therapy

• Initiate combination therapy with erythromycin (200-250 mg IV every 6-8 hours) and metoclopramide (10 mg IV every 6 hours) as first-line pharmacologic intervention. 2
• Combination therapy is superior to single-agent therapy for feeding intolerance and ileus. 2
• Discontinue prokinetics after 72 hours due to rapid tachyphylaxis—do not continue beyond this timeframe. 2

Second-Line: Neostigmine for Colonic Ileus

• Use neostigmine (2-2.5 mg IV over 3-5 minutes) for established colonic ileus (Ogilvie's syndrome) not responding to simple measures and associated with IAH. 1, 6
• Monitor for bradycardia and have atropine available—neostigmine is contraindicated in mechanical obstruction. 6
• Neostigmine is effective for large bowel pseudo-obstruction but does not address small bowel dysmotility. 6

Emerging Option: Prucalopride

• Prucalopride (2 mg daily) may be effective for non-severe inflammatory/ischemic paralytic ileus, with predominant effect on the large intestine. 8
• Maximum effect occurs on day 3 of therapy, with significant reduction in large bowel diameter and abdominal circumference. 8
• This is not yet standard of care but represents a promising option when conventional prokinetics fail. 8

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Step 4: Nutritional Management During Ileus

Enteral Nutrition Strategy

• Do NOT routinely monitor gastric residual volumes (GRVs)—only check when clinical signs appear (vomiting, abdominal distension, pain). 2
• Continue enteral feeding unless GRV exceeds 500 mL per 6 hours. 2
• Use trophic/hypocaloric feeds (20-25 kcal/kg/day) and advance as tolerated rather than stopping enteral nutrition entirely. 2
• Use energy-dense formulas (>1.25 kcal/mL) with high protein content (20% protein) and continuous rather than bolus feeding. 2

Escalation to Post-Pyloric Feeding

• If feeding intolerance persists despite prokinetic therapy, place a post-pyloric (jejunal) feeding tube. 2
• Post-pyloric feeding reduces GRV and incidence of feeding intolerance. 2

Parenteral Nutrition

• Do NOT initiate parenteral nutrition in the first 7 days if enteral feeding is feasible, even with intolerance. 2
• Parenteral nutrition increases infection risk and should be reserved for patients who cannot tolerate any enteral nutrition. 1

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Step 5: Fluid Management

Avoid Positive Fluid Balance

• Use a protocol to avoid positive cumulative fluid balance after acute resuscitation is completed and inciting issues are addressed. 1
• Positive fluid balance promotes third-space fluid accumulation, bowel edema, and worsening IAH. 1, 3
• Target neutral or negative fluid balance once hemodynamically stable. 1

Percutaneous Catheter Drainage (PCD)

• Consider PCD to remove intraperitoneal fluid when obvious fluid is present and IAH/ACS exists. 1
• PCD may alleviate the need for decompressive laparotomy. 1

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Step 6: Surgical Intervention for Abdominal Compartment Syndrome

Indications for Decompressive Laparotomy

• Perform decompressive laparotomy in cases of overt ACS (IAP >20-25 mmHg with organ dysfunction) that does not respond to medical management. 1
• The "open abdomen approach" with temporary abdominal closure is the therapy of choice for ACS. 1, 3
• Use negative pressure wound therapy for open abdominal wounds. 1
• Make conscious efforts to obtain early or same-hospital-stay fascial closure. 1

Decompressive Colonoscopy

• Colonic tube placement after decompressive colonoscopy may be effective in reducing intestinal dilatation in Ogilvie's syndrome. 3

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Step 7: Monitoring and Re-evaluation

Clinical Monitoring

• Monitor for signs of bowel ischemia or perforation: worsening abdominal pain, peritoneal signs, lactic acidosis, fever. 3
• Serial abdominal examinations and imaging (plain radiography or CT) to assess bowel dilatation. 8
• Measure abdominal circumference daily as a surrogate marker for bowel distension. 8

Antibiotic Duration

• In patients with intra-abdominal infection and adequate source control, limit antibiotics to 3-5 days. 1
• If signs of peritonitis or systemic illness persist beyond 5-7 days, perform diagnostic investigation to determine if additional surgical intervention is necessary. 1

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Common Pitfalls and Caveats

• Do NOT delay antibiotics in suspected infection—bacterial infections are major triggers for ileus in critically ill patients. 4
• Do NOT continue prokinetics beyond 72 hours—tachyphylaxis renders them ineffective and wastes resources. 2
• Do NOT overfeed during the acute phase (>25 kcal/kg/day)—this worsens outcomes. 2
• Do NOT ignore IAP monitoring—unrecognized ACS is a preventable cause of death. 1, 3
• Do NOT use lactulose for paralytic ileus—it causes abdominal distention and worsens ileus. 9
• Do NOT assume all bowel distension is benign ileus—always rule out mechanical obstruction, ischemia, and perforation. 3