Gastro-oesophageal reflux disease (GORD) is a common condition, where acid from the stomach leaks up into the oesophagus (gullet). The acid perfusion (Bernstein) test is used to determine if chest pain is caused by acid reflux. For the acid perfusion test, a thin tube is passed through one nostril, down the back of the throat, and into the middle of the esophagus. A dilute, acid solution and a physiologic salt solution (similar to the fluid that bathes the body’s cells) are alternately poured (perfused) through the catheter and into the esophagus. The patient is unaware of which solution is being infused. If the perfusion with acid provokes the patient’s usual pain and perfusion of the salt solution produces no pain, it is likely that the patient’s pain is caused by acid reflux.
When acid refluxes back into the esophagus in patients with GERD, nerve fibers in the esophagus are stimulated. This nerve stimulation results most commonly in heartburn, the pain that is characteristic of GERD. Heartburn usually is described as a burning pain in the middle of the chest. It may start high in the abdomen or may extend up into the neck. In some patients, however, the pain may be sharp or pressure-like, rather than burning. Such pain can mimic heart pain ( angina ). In other patients, the pain may extend to the back.
Reflux occurs when stomach contents escape upward into the esophagus, the tube connecting the mouth to the stomach. This takes place when the muscular opening to the stomach – called the lower esophageal sphincter – fails to open and close properly. Stomach contents can irritate the lining of the esophagus, commonly leading to heartburn. Acid reflux is a common problem. A June 2014 article published in the journal “Gut” reported that an estimated 18 to 28 percent of U.S. adults experience symptoms of acid reflux at least once per week. Pain that may be experienced with acid reflux typically consists of a dull burning sensation in the middle of the chest that can radiate toward the back of the throat.
pH testing has uses in the management of GERD other than just diagnosing GERD. For example, the test can help determine why GERD symptoms do not respond to treatment. Perhaps 10 to 20 percent of patients will not have their symptoms substantially improved by treatment for GERD. This lack of response to treatment could be caused by ineffective treatment. This means that the medication is not adequately suppressing the production of acid by the stomach and is not reducing at bing acid reflux. Alternatively, the lack of response can be explained by an incorrect diagnosis of GERD. In both of these situations, the pH test can be very useful. If testing reveals substantial reflux of acid while medication is continued, then the treatment is ineffective and will need to be changed. If testing reveals good acid suppression with minimal reflux of acid, the diagnosis of GERD is likely to be wrong and other causes for the symptoms need to be sought.
As discussed above, reflux of acid is more injurious at night than during the day. At night, when individuals are lying down, it is easier for reflux to occur. The reason that it is easier is because gravity is not opposing the reflux, as it does in the upright position during the day. In addition, the lack of an effect of gravity allows the refluxed liquid to travel further up the esophagus and remain in the esophagus longer. These problems can be overcome partially by elevating the upper body in bed. The elevation is accomplished either by putting blocks under the bed’s feet at the head of the bed or, more conveniently, by sleeping with the upper body on a foam rubber wedge. These maneuvers raise the esophagus above the stomach and partially restore the effects of gravity. It is important that the upper body and not just the head be elevated. Elevating only the head does not raise the esophagus and fails to restore the effects of gravity.