Current therapies to shorten postoperative ileus
ABSTRACTPostoperative ileus delays hospital discharge, increases costs, and contributes to adverse outcomes. A variety of neural and chemical factors are involved. To shorten the duration of postoperative ileus, we may need to establish standard plans of care that favor earlier feeding, use of nasogastric tubes only on a selective basis, and prokinetic drugs as needed.
KEY POINTS
- Postoperative ileus can selectively affect the stomach, small intestine, or large intestine, each with different causes and clinical presentation and each managed differently.
- Laparoscopic surgery is associated with a shorter duration of postoperative ileus compared with open surgery.
- Epidural anesthesia reduces the need for opiate analgesia after surgery and thus shortens the duration of postoperative ileus.
- Drugs are being developed that block the effects of opiates on the gut while preserving their pain-relieving properties.
STRATEGIES TO PREVENT AND TREAT ILEUS
Many strategies have been applied to prevent and manage postoperative ileus, ranging from changes in surgical technique, supportive care, and patient-initiated activities, to pharmacologic intervention.
Epidural anesthesia shortens ileus, reduces the need for narcotics
Epidural anesthesia has shown promise not only in improving pain control, but also in shortening the period of postoperative ileus. Most surgical patients either receive an epidural catheter before surgery, which is left in place for postoperative pain control, or are given patient-controlled analgesia with a narcotic. Generally, the surgeon chooses the pain control method.
Thoracic epidural analgesia has been shown to hasten the return of bowel function by 1 to 2 days and to reduce the need for opiates compared with systemic opioids alone.21–26 A likely explanation is that epidural anesthesia interferes with the afferent and efferent sympathetic reflex arcs. The level of the epidural placement is important: a thoracic epidural is needed to effectively block these sympathetic pathways.
Laparoscopic surgery is less traumatic
Laparoscopy has changed the landscape of surgery over the past few decades. Some of the most common surgical procedures (appendectomy, cholecystectomy) are now done mainly via the laparoscope, as are many procedures that are more complex.
Laparoscopic surgery has several advantages over open surgery. With smaller incisions, it is less traumatic to the body. The systemic inflammatory response appears to be less vigorous after laparoscopic surgery than after open surgery, as measured by circulating levels of interleukin 1, interleukin 6, and C-reactive protein.27
The length of stay after a laparoscopic procedure is shorter than after an open procedure for several reasons, not the least of which is a shorter duration of postoperative ileus. Animal studies show that intestinal recovery is faster after laparoscopic procedures than after open procedures.28–30 In a study in which their other care was comparable, significantly fewer patients undergoing laparoscopic colectomy had emesis or needed their nasogastric tube to be reinserted than patients who underwent an open operation, and their length of stay was shorter.31
As technology continues to advance in minimally invasive surgery, it is reasonable to expect these trends to continue.
Nasogastric tubes in selected cases
Patients are often allowed nothing by mouth or only minimal oral intake immediately after abdominal surgery, with or without nasogastric decompression. The role of nasogastric decompression has long been a topic of controversy. In a meta-analysis of 26 trials with 3,964 patients, the groups in which all patients routinely received a nasogastric tube had higher rates of pneumonia, fever, and atelectasis and longer duration to resumption of oral feeding than the groups in which nasogastric tubes were used selectively.32
Most clinicians agree that nasogastric tubes are uncomfortable and do little to prevent postoperative ileus. However, in selected cases they are useful for managing intractable vomiting and for preventing aspiration of gastric contents.
Early enteral feeding
Evidence is mounting that early postoperative enteral feeding may be advantageous for recovery.
In 1,173 patients undergoing both upper and lower gastrointestinal surgery in 13 trials, fewer patients died who were randomized to receive enteral feeding within 24 hours.33 There were also fewer infectious complications and anastomotic problems and a shorter length of stay, but these differences were not statistically significant. Vomiting was more common in the early-feeding groups but did not lead to higher rates of morbidity. Enteral feeding was by the oral, nasoduodenal, or nasojejunal routes, depending on the type of surgery performed.
Whether the number of calories given affects the outcome remains to be clarified, but at least for now it seems that feeding patients early in the course of their recovery is not detrimental and may in fact be beneficial.
Gum-chewing
Gum-chewing has been studied over the last decade as a form of sham feeding to stimulate bowel recovery after surgery. The presumed mechanism of action is vagal cholinergic (parasympathetic) stimulation of the gastrointestinal tract, similar to oral intake but with theoretically less risk of vomiting and aspiration.
In five such trials in patients undergoing colon resection, gum-chewing shortened the time until first flatus and bowel movement, but made no significant difference in length of stay.34
At the very least, gum-chewing immediately after surgery is a cheap and harmless strategy for reducing postoperative ileus, and it might make the patient more comfortable.
