Postoperative Ileus

Postoperative ileus is transient impairment of coordinated gastrointestinal motility after surgery without a mechanical obstruction.

Some degree of reduced motility is expected after abdominal surgery. It becomes clinically significant when bowel dysfunction is prolonged enough to cause persistent distension, nausea, vomiting, inability to tolerate enteral intake or delayed recovery.

Contributors include bowel manipulation, inflammatory responses, opioids, excessive IV fluid, hypokalaemia, hypomagnesaemia, sepsis and major intra abdominal complications.

Persistent ileus must never be accepted automatically as benign. Anastomotic leak, abscess, bowel injury and mechanical obstruction must be excluded when recovery is abnormal.

Typical findings include:

• Abdominal distension
• Nausea or vomiting
• Delayed tolerance of oral intake
• Failure to pass flatus or stool
• Mild diffuse discomfort rather than severe colic
• Reduced bowel activity

Severe colicky pain, focal tenderness or a discrete transition pattern is more consistent with mechanical obstruction.

Fever, persistent tachycardia, increasing pain or inflammatory deterioration suggests a postoperative complication rather than uncomplicated ileus.

Check potassium, magnesium, renal function and other clinically relevant biochemical abnormalities.

CT abdomen and pelvis with IV contrast: use when prolonged or worsening symptoms require exclusion of mechanical obstruction, anastomotic leak or intra abdominal collection; postoperative ileus shows diffuse bowel dilatation without a mechanical transition point.

Treat reversible causes.

Correct hypokalaemia and hypomagnesaemia.

Reduce systemic opioids using multimodal analgesia.

Mobilise early.

Avoid both hypovolaemia and unnecessary postoperative fluid loading.

Nasogastric decompression is not routine. Use it for persistent vomiting, substantial gastric distension or aspiration risk.

Early enteral feeding is beneficial after uncomplicated colorectal surgery. ASCRS and SAGES recommend offering a regular diet within 24 hours following elective colorectal surgery rather than waiting routinely for passage of flatus or stool.

Chewing gum can be used as a low risk adjunct in selected patients, but it is not a substitute for identifying complications.

Alvimopan can shorten gastrointestinal recovery after selected open colorectal resections when incorporated from the perioperative period:

Alvimopan 12 mg orally before surgery, then 12 mg orally twice daily after surgery for a maximum of 7 days and no more than 15 total doses.

It is primarily a prevention and enhanced recovery drug rather than rescue treatment once established severe ileus is present. Avoid it in patients who received therapeutic opioid doses for more than 7 consecutive days immediately before treatment.

Persistent ileus with fever, tachycardia, focal pain, worsening leukocytosis or failure to progress should trigger CT and assessment for anastomotic leak, abscess, obstruction or bowel ischaemia rather than continued observation alone.