Post-Op Ileus

Question 1

What is post-op ileus?

Answer 1

Post-operative ileus describes a deceleration or arrest in intestinal motility following surgery. It is classified as a functional bowel obstruction and is very common, particularly after abdominal surgery or pelvic orthopaedic surgery.

Question 2

What other post-op complicatio may post-op ileus present similarly to?

Answer 2

Anastomotic leak (as pus or faeces will irritate the bowel and often cause it cease functioning).

Question 3

What are the risk factors for post-op ileus?

Answer 3

Patient factors:

• Increased age
• Electrolyte derangement (e.g. Na⁺, K⁺ and Ca²⁺ derangement)
• Neurological disorders (e.g. Dementia or Parkinson’s Disease)
• Use of anti-cholinergic medication

Surgical factors:

• Use of opioid medication
• Pelvic surgery
• Extensive intra-operative intestinal handling
• Peritoneal contamination (by free pus or faeces)
• Intestinal resection

Question 4

What are the signs and symptoms of post-op ileus?

Answer 4

A post-operative ileus is simply a delay in the return of normal bowel function. As a result, the symptoms of post-operative ileus may be the same as those of a mechanical obstruction.

Common presenting features therefore are:

• Failure to pass flatus or faeces
• Sensation of bloating and distention
• Nausea and vomiting (or high NG output)

Question 5

How does post-op ileus present on examination?

Answer 5

On examination, there will be abdominal distention and absent bowel sounds (whereas in mechanical obstruction there are classically ‘tinkling’ bowel sounds present).

Question 6

What investigations should be ordered for post-op ileus?

Answer 6

In the patients with suspected post-operative ileus, the aim of the investigations are to rule out more serious pathologies and determine any underlying cause.

Initial routine bloods should be taken, including FBC and CRP (to check inflammatory markers), and U&Es (as fluid shifts can occur within the adynamic bowel leading to AKI). Electrolytes, including Ca²⁺, PO₄³⁻, and Mg²⁺, should also be checked and corrected accordingly.

A CT scan abdomen and pelvis (often with oral contrast) will confirm the diagnosis and importantly also rule out any intra-abdominal collections or anastomotic leaks.

Question 7

Briefly describe the management of post-op ileus

Answer 7

As long as serious pathology (e.g. anastomotic leak) has been excluded, the management of post-operative ileus is conservative.

Any established postoperative ileus should be initially managed with:

• Nil-by-mouth (NBM), ensuring adequate maintenance intravenous fluids +/- NG tube
  
  • Start a strict fluid-balance chart to monitor input-output
• Daily bloods, including electrolytes
  
  • Correct any electrolyte abnormalities and monitor for acute kidney injury
• Encourage mobilisation as tolerated
• Reduce opiate analgesia and any other bowel mobility reducing medication

It is important to warn patients that once it does settle, they may well have very watery stool for the first 2–3 bowel movements.

Question 8

What are the prophylactic measures for post-op ileus?

Answer 8

To reduce the risk of developing post-operative ileus, preventive steps include:

• Minimise intra-operative intestinal handling
• Avoid fluid overload (causing intestinal oedema)
• Minimise opiate use
• Encourage early mobilisation