Updated March 07, 2014.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

It is a strange fact that doctors and nurses may seem very concerned about your ability to “pass gas” after surgery.  It is more than reasonable to wonder why there is such an unusual amount of interest in what is typically a pretty personal part of day to day life. Believe it or not, there is a good answer for all of the concern about your ability to release gas after having anesthesia. 

When you are recovering in the post anesthesia care unit (PACU) you may be told to notify your nurse if you pass gas.

  In the pediatric setting, a child may be told that the nurse would like to know if they “toot” or “fart”, which may cause some giggles or shyness.  

Postoperative Ileus

After surgery, or more specifically, after the medications that are given during surgery, there is the possibility of a complication called a postoperative ileus (POI).  This is a delay in gastric motility, or the movements that push food through the gastrointestinal tract, and it is common after surgery.  The severity can range from barely noticeable to a serious complication that requires significant medical treatment.  

In the simplest terms, a postoperative ileus means that it takes your intestines longer to wake up from anesthesia than the rest of you.  The ability to pass gas is a clear sign that your gastrointestinal tract is waking up and that POI is resolving, if present.  This is why nurses and doctors care about whether or not you pass gas in the hours after surgery, it is a sign that your digestive organs are returning to their normal state.

For some surgeries, the patient performs a bowel preparation prior to the procedure, which cleans the stool from the intestines.  For these patients, it may be several days before they have stool, so passing gas is one of the earliest signs of their intestines waking up.

In the case of outpatient surgery, passing gas may be required before you are able to go home.  The staff doesn’t want to send you home with a potentially serious complication, so don’t even think about being bashful, let them know if you have successfully passed gas.

Causes of Postoperative Ileus

Researchers have not come to an agreement on why postoperative ileus happens. One theory is that the sympathetic nervous system, which normally decreases the amount of movement done by the intestines, temporarily has greater control over the intestines than the parasympathetic nervous system, which increases the movement of the intestines.  

Another theory suggests that POI is caused during abdominal procedures by the manipulation of the intestines during surgery, such as moving them out of the way to reach other body structures, or performing surgery directly on them. This starts a cascade effect when the white blood cells in the intestine are stimulated by the surgical activity and trigger other types of cells to move to the area.   Other theories point to electrolyte imbalances and the use of opioids for pain control.

Symptoms Associated With Postoperative Ileus

For most patients, the delay in gastric motility is brief, but for others the complication requires a longer hospital stay than intended.  For those patients, the symptoms of an ileus may be much more severe.

Signs and Symptoms of Postoperative Ileus:

• Nausea
• Bloating
• Vomiting
• Abdominal tenderness or pain
• Passing gas/stool is delayed or not possible

Risk Factors for Postoperative Ileus

Patients who have surgery that requires manipulation of the intestines, or surgery performed on the intestines are at a much higher risk of developing postoperative ileus. The severity of POI may also be increased in these patients.  Patients receiving opioid medications for pain relief are also at a higher risk of developing POI, as are patients who already have issues with their intestines.

Preventing Postoperative Ileus

While preventing postoperative ileus may not entirely be possible, there are ways to minimize the risk.  Patients receiving epidural anesthesia rather than general anesthesia typically have a quicker recovery from this complication.  Minimally invasive techniques also may decrease the duration of postoperative ileus when compared to the more traditional surgical techniques.  Walking after surgery, when appropriate, may play a small role in helping reverse ROI. 

One of the simplest solutions, which is showing promise in research studies, may be to chew gum after surgery.  Several recent studies showed a decrease in the duration of postoperative ileus in patients who chewed gum and there was some evidence that their hospital stay was shorter than non-gum chewers.

Source:

Pathogenesis and Management of Postoperative Ileus. James Carroll and Karim Alavi. Accessed February, 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2780226/?