Post-operative ileus describes a deceleration or arrest in intestinal motility following surgery. It is classified as a functional obstruction of the bowel. It is a common phenomenon, with many surgical patients having a degree of physiological ileus post-operatively.
Remember however that although innocent in the majority of patients, it can be a sign of other intra-abdominal pathology, in particular a collection or anastomotic leak (as pus or faeces will irritate the bowel and often cause it cease functioning).
Note: It is important to appreciate that any patient with a bowel obstruction picture who fails to progress as expected after a bowel resection has an anastamotic leak until proven otherwise.
Post-operative ileus has been shown to lengthen hospital stay and increased hospital costs. Previous studies have estimated that an average of 8 days in added on to a hospital stay with post-operative ileus and the overall annual expenditure secondary to postoperative ileus is around $750 million to $1 billion in the US.
- 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
Patients with a post-operative ileus will present with:
- Failure to pass flatus or faeces
- Sensation of bloating and distention
- Nausea and vomiting / high NG output
On examination, there will be abdominal distention and absent bowel sounds; importantly, this is a key difference to the presentation of a mechanical obstruction (which typically has ‘tinkling’ bowel sounds present)
A post-operative ileus will delay to 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.
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.
- U&Es and calcium levels
- Na+, K+ and Ca2+ abnormalities may cause paralytic ileus
- Inflammatory markers (WCC, CRP) to look for intra-abdominal collections or leaks
An abdominal X-ray (AXR) can also be requested, which may demonstrate small or large bowel dilatation.
A CT scan (often with oral contrast) will confirm diagnosis and rule out any collections / anastomotic leak. This is only really useful 3-5 days after surgery.
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:
- Daily U&Es
- Correct electrolyte abnormalities present and monitor for acute kidney injury (AKI)
- Reduce opiate analgesia and any other bowel mobility reducing medication
It is important to warn patients that once it does settle, they will get very watery diarrhoea for the first 2 – 3 bowel movements.
Prolonged cases may warrant insertion of a nasogastric (NG) tube on free drainage and catheterising with a fluid balance chart started.
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
Gum chewing as part of post-operative recovery following open GI surgery has been shown in a meta-analysis to reduce the period of post-operative ileus, as has enhanced recovery programs.