Overview
Definition:
Postoperative ileus (POI) is a transient, physiological functional impairment of intestinal motility that occurs after abdominal surgery, characterized by a delay in the return of bowel function, leading to symptoms like abdominal distension, nausea, vomiting, and inability to pass flatus or stool.
Epidemiology:
POI is a common complication after abdominal surgery, with an incidence ranging from 10% to 30% depending on the extent and type of surgery
It is more prevalent after open procedures compared to laparoscopic ones
Risk factors include prolonged operating time, intra-abdominal inflammation, large bowel resection, and opioid use.
Clinical Significance:
Prolonged POI leads to increased hospital stay, higher healthcare costs, delayed oral intake, and potential complications such as dehydration, electrolyte imbalances, and surgical site infections
It is a significant determinant of patient recovery and resource utilization post-surgery, making its prevention and timely management crucial for surgical trainees.
Clinical Presentation
Symptoms:
Abdominal distension
Nausea and vomiting, often bilious
Abdominal pain, typically diffuse and crampy
Inability to pass flatus
Inability to pass stool
Early postoperative, patients may have some flatus, but this ceases with developing ileus.
Signs:
Abdominal distension and tympany on percussion
Diminished or absent bowel sounds on auscultation
Tenderness on palpation, but often benign early on
Vital signs may be stable unless complications arise (e.g., dehydration, sepsis).
Diagnostic Criteria:
No single definitive diagnostic criterion exists
diagnosis is primarily clinical, supported by investigations
It is characterized by the failure of bowel function to return within an expected timeframe post-operatively, typically >72 hours for the colon and >48 hours for the small bowel after non-manipulative surgery, or longer after significant bowel manipulation or inflammation.
Diagnostic Approach
History Taking:
Detailed surgical history: type of surgery, duration, enterotomies, bowel resections, intra-abdominal complications
Pain characteristics: onset, severity, radiation, alleviating/aggravating factors
Vomiting: frequency, character (bilious/feculent)
Flatus/stool passage: last bowel movement
Medications: especially opioids, prokinetics, anticholinergics
Past surgical history: adhesions, previous bowel issues.
Physical Examination:
Assess general appearance: distressed, comfortable
Abdominal examination: inspection for distension and scars, auscultation for bowel sounds (normal, hyperactive, hypoactive, absent), percussion for tympany, palpation for tenderness and guarding
Rectal examination: to rule out obstruction and assess stool in the vault.
Investigations:
Abdominal X-ray: shows dilated loops of small and/or large bowel with air-fluid levels, often generalized distension
CT abdomen/pelvis: more sensitive than X-ray, can differentiate between functional ileus and mechanical obstruction, identify causes of obstruction (adhesions, hernia), and detect complications like ischemia or perforation
Electrolytes and renal function tests: to assess hydration and electrolyte imbalances
Complete blood count: to check for infection or anemia.
Differential Diagnosis:
Mechanical bowel obstruction (adhesions, incarcerated hernia, intussusception, malignancy)
Ischemic colitis
Volvulus
Intra-abdominal abscess
Peritonitis
Postoperative fluid overload.
Management
Initial Management:
Bowel rest: NPO (Nil Per Os)
Nasogastric (NG) tube decompression: for symptomatic relief of nausea/vomiting and distension
Intravenous fluid resuscitation: to correct dehydration and electrolyte imbalances
Pain control: judicious use of analgesics, favoring non-opioids where possible.
Medical Management:
Electrolyte correction: particularly potassium and magnesium
Nutritional support: often parenteral nutrition (TPN) if prolonged ileus is anticipated
Prokinetic agents: generally not recommended for established POI, but may have a role in very specific scenarios or early postop phases (e.g., erythromycin in specific settings).
Surgical Management:
Surgical intervention is indicated if POI is prolonged (>7-10 days) and conservative measures fail, or if there is suspicion of mechanical obstruction, bowel ischemia, or perforation
Laparoscopic adhesiolysis for adhesions
Re-exploration for mechanical obstruction or retained foreign bodies
Bowel resection if ischemia or perforation is present.
Supportive Care:
Close monitoring of vital signs, fluid balance, and abdominal examination
Regular repositioning to prevent atelectasis
Early mobilization as tolerated
Careful management of nasogastric tube output
Monitor for signs of complications like fever, increasing pain, or worsening distension.
Prevention Strategies
Preoperative Optimization:
Adequate patient hydration and nutritional status
Correction of anemia and electrolyte abnormalities
Patient education about expectations.
Intraoperative Techniques:
Minimally invasive surgery (laparoscopy) where appropriate
Gentle handling of bowel tissues
Avoidance of excessive retraction
Judicious use of bowel lubricants
Limiting prolonged retraction
Minimal use of drains where not indicated.
Postoperative Measures:
Early mobilization: encouraging patients to ambulate as soon as possible
Epidural analgesia or multimodal pain management to reduce opioid dependence
Opioid-sparing analgesia: multimodal approaches including NSAIDs and regional blocks
Prophylactic use of laxatives or suppositories in specific contexts (e.g., after colorectal surgery)
Avoidance of routine nasogastric tubes in uncomplicated cases
Early oral feeding trials when clinically appropriate, guided by return of bowel sounds or passage of flatus.
Complications
Early Complications:
Dehydration and electrolyte disturbances
Nasogastric tube dislodgement or obstruction
Pulmonary complications due to immobility and distension
Surgical site infections
Wound dehiscence.
Late Complications:
Adhesions leading to chronic bowel obstruction
Malnutrition due to prolonged NPO status or malabsorption
Incisional hernias.
Prevention Strategies:
Strict adherence to evidence-based multimodal pain management to minimize opioid use
Aggressive ambulation and early mobilization
Judicious use of nasogastric tubes
Careful fluid and electrolyte management
Timely initiation of enteral or parenteral nutrition if prolonged ileus is suspected
Prompt investigation of any signs suggestive of mechanical obstruction or ischemia.
Key Points
Exam Focus:
Differentiate functional ileus from mechanical obstruction
Understand the role of opioid analgesia and strategies to mitigate its effect
Recognize risk factors for POI and evidence-based prevention strategies
Indications for NG tube decompression and TPN
Criteria for surgical re-exploration.
Clinical Pearls:
Auscultate for bowel sounds: absent bowel sounds in the presence of distension and vomiting is highly suggestive of ileus
Palpate gently: significant rigidity and rebound tenderness might suggest something more than simple ileus, warranting urgent evaluation
Serial abdominal exams are crucial for monitoring progress or deterioration
Always consider mechanical obstruction in the differential, especially if symptoms are severe or prolonged.
Common Mistakes:
Over-reliance on opioid analgesia without considering alternatives
Failure to mobilize patients early
Not decompressing significant gastric distension with an NG tube
Delaying diagnosis of mechanical obstruction or ischemia
Starting oral feeds too early in the presence of significant ileus symptoms.