Postoperative gastrointestinal tract dysfunction: An overview of causes and management strategies

OTHER STRATEGIES TO REDUCE POSTOPERATIVE GI DYSFUNCTION

In addition to fluid loading, a number of other methods have been studied in an attempt to reduce the incidence of postoperative GI tract dysfunction.

Epidural neostigmine: Improvement in some measures

Epidural neostigmine was compared with saline control in a randomized study of 45 patients scheduled for abdominal aortic surgery.³⁰ Time to first bowel sounds and time to first flatus were significantly shorter in the neostigmine group, but time to first defecation and the incidence of post­operative complications were similar between the groups.

Laxatives speed return of GI function

In a study of 53 women undergoing fast-track hysterectomy, recovery of GI tract function was faster in those randomized to receive laxatives (magnesium oxide and disodium phosphate) starting 6 hours postoperatively compared with those receiving placebo.³¹ Median time to first defecation was reduced from 69 hours in the placebo group to 45 hours in the laxative group (P < .0001), and postoperative hospitalization was shortened by a median of 1 day in the laxative group. There were no significant between-group differences in pain scores, postoperative nausea and vomiting, or the use of morphine or antiemetics.

Fentanyl reduces gastric myoelectrical activity

Intravenous administration of the opioid fentanyl significantly reduced gastric myoelectrical activity in an uncontrolled study of 20 patients undergoing elective surgery, but wide variation in effect was observed among patients.³² There was no correlation between the myoelectrical outcome and the presence of polymorphisms of the mu-opioid receptor gene.

Systemic lidocaine accelerates return of bowel function

Perioperative administration of systemic lidocaine, given as a 1.5-mg/kg bolus followed by continuous infusion at 2 mg/min, accelerated the return of bowel function and shortened the length of hospital stay compared with placebo in a randomized study of 60 colorectal surgery patients.³³

Early oral feeding cuts length of stay

A recent meta-analysis of randomized trials found that early oral intake of fluids and food after major abdominal gynecologic surgery was associated with an increased risk of nausea but a reduced length of hospital stay.³⁴ The authors recommended an individualized approach to early feeding, and called for cost-effectiveness and patient satisfaction studies.

Mosapride improves gastric emptying

Mosapride is a 5-HT₄ agonist that has been shown to improve gastric emptying in a randomized controlled study of 40 patients undergoing laparoscopic colectomy.³⁵ Time to first postoperative bowel movement, time to maximal gastric emptying rate, and postoperative hospital stay were all significantly shorter in patients receiving mosapride versus control. Mosapride is not currently approved for marketing in the United States.

Mu-opioid antagonists: Some show promise, others don’t

Mu-opioid receptor antagonists have been developed primarily to reverse opioid-induced bowel dysfunction. Commercially available drugs in this class include alvimopan, methylnaltrexone, nalbuphine, and naloxone. A recent meta-analysis of 23 randomized controlled studies of these agents for opioid-induced bowel dysfunction concluded that alvimopan and methylnaltrexone were superior to placebo but that evidence was insufficient for the safety or efficacy of naloxone and nalbuphine.³⁶

Nasogastric decompression: Usually more harm than benefit

Prophylactic nasogastric decompression is an intervention devoid of evidence. A meta-analysis of 33 studies encompassing 5,240 patients randomized to routine nasogastric tube placement, selective nasogastric tube use, or no nasogastric tube placement after abdominal surgery found no advantage to routine nasogastric tube use.³⁷ In fact, patients not receiving routine tube placement had a significantly earlier return of bowel function and a significant decrease in pulmonary complications. The incidence of anastomotic leak was not different among the groups. Routine tube use was associated with a lower incidence of vomiting but more patient discomfort. The clear conclusion is that, in most situations, elective placement of a nasogastric tube only causes harm.

Chewing gum: A simple intervention that works

In a recent meta-analysis of five randomized controlled trials, the simple intervention of gum chewing after colorectal surgery significantly accelerated the time to flatus and time to defecation, and was associated with a nonsignificant trend toward a shorter postoperative hospital stay.³⁸

CONCLUSIONS ON MANAGEMENT

Traditional measures intended to reduce the incidence of postoperative GI tract dysfunction—administration of prokinetic drugs, placement of nasogastric tubes, avoidance of food and fluids—are not beneficial and are often harmful. Administration of targeted amounts of fluid to optimize ventricular filling and end-organ perfusion has repeatedly been demonstrated to improve outcomes, particularly those related to GI tract perfusion and function. Administration of larger volumes of colloid, to achieve predetermined increases in stroke volume, improves gut perfusion and reduces the incidence of GI tract dysfunction.

Many simple, inexpensive, and readily available strategies for preventing or reversing postoperative GI tract dysfunction have some degree of evidence-based support and should be considered. I would recommend a multimodal approach that includes a limited surgical incision, regional local anesthesia without use of opioids, immediate postoperative mobilization, early enteral feeding, and postoperative gum chewing.¹ Such an approach promises to reduce GI tract dysfunction and other postoperative complications as well as to shorten hospital stay.