Hepatic Failure/GI/Endocrine Emergencies

moves intestinal contents distally.

During periods of fasting postoperatively, the contractility of the stomach and small intestine is

entirely dependent on the migrating motor complex.

Inflammation of the GI tract after surgery, inhibitory neural reflexes, and the release of inhibitory

neurotransmitters such as nitrous oxide, substance P, and vasoactive intestinal peptide may lead to

decreased activity of migrating motor complex.

Exacerbating factors

Anesthesia: Delayed gastric emptying has been observed with the use of halothane, enflurane, and

atropine.

Postoperative opioids: Opioids, through agonism at the mu2-opioid receptor, slow GI motility

mainly by decreasing colonic motility. High doses and prolonged courses postoperatively can

contribute to paralytic ileus.

Other medications known to decrease GI motility are often given perioperatively (e.g.,

anticholinergics).

POI is typically characterized by abdominal distension, lack of bowel sounds, delayed passage of flatus

or stool, and accumulation of gas and stool in the bowels, which may lead to nausea and vomiting.

radiographs to identify air and dilated loops of bowel.

An abdominal CT scan can be used to rule out a mechanical obstruction.

Use of epidural anesthesia

Epidural blockade may improve POI by reducing local sympathetic and inflammatory response

postoperatively and increasing splanchnic blood flow. It may also reduce postoperative opioid use.

Several studies of epidural anesthesia have shown reductions in POI. Most studies that showed

benefit used thoracic epidural blockade and administered epidural anesthesia for at least 48–72

hours.

compared with open abdominal procedures. However, studies have shown reductions in inflammatory

response (e.g., cytokine production) and reduced postoperative pain with laparoscopic procedures,

which may affect POI.

NG decompression

Historically, NG tubes were placed in most patients for gastric decompression and used until

normal GI function returned.

In a meta-analysis of 26 trials including 4000 patients, the use of NG tube insertion was routinely

associated with fever, atelectasis, and pneumonia, though patients treated without NG tubes did

have more abdominal pain and vomiting. The study concluded that for every patient who required

NG tube insertion, 20 patients could be treated effectively without NG tube insertion and that NG

tubes should be used selectively because of concerns for adverse effects.

Enteral feeding

Traditionally, enteral feeds were delayed postoperatively until after ileus was resolved.

Recent data from several randomized controlled trials show a modest improvement in POI

resolution from early enteral feedings, typically initiated within the first 24 hours postoperatively.

This effect probably results from stimulation of the bowel.