NEW YORK (Reuters Health) – Combined multichannel intraluminal impedance monitoring (MII) and pH monitoring in the esophagus detects gastroesophageal reflux (GER) in children more accurately than pH monitoring alone, a German team reports. In fact, simply monitoring pH misses nearly half of affected children, the researchers found.

Dr. Denisa Pilic at Children’s University Hospital Bochum at St Josef Hospital, Ruhr University, and colleagues report their findings in The Journal of Pediatrics online October 29.

They note that pH monitoring is still widely used to diagnose GER in children, but it does not detect reflux as a retrograde bolus movement. However, that can be done with a MII catheter: multiple impedance measurements along segments of the catheter within the esophagus detect bolus movements and their direction via changes in electric impedance between two segments. An additional pH probe indicates whether the bolus is acidic or non-acidic.

To validate the use of MII-pH monitoring in daily clinical practice, the researchers analyzed results from 700 children with symptoms of GER. Monitoring measurements were abnormal in 270 of the patients. On further analysis, the team found that 101 (37%) showed abnormal MII-pH results, 49 (18%) had only pathological pH measurements and 120 (45%) had an abnormal MII recording only.”

In other words, “45% of the patients with abnormal GER would not have been recognized by 24-hour pH measurement alone.”

However, one of the problems with the MII methodology is interpreting the data in children. “Normal values for the number of RBMs (retrograde bolus movements) in children detected by MII are not yet available,” Dr. Pilic and colleagues note. “Based on our experience in analyzing our data, we considered an MII measurement abnormal if it showed a high number of RBMs or a positive symptom association.”

Still, the authors conclude that, consistent with new guidelines, “MII-pH should be the standard test for detecting GER in children of all age groups.”

In the Journal, Dr. Philip E. Putnam, with Cincinnati Children’s Hospital Medical Center, Ohio has an editorial on the topic, although not specifically related to the study by Dr. Pilic’s team. He calls the editorial, “Obituary: The Death of the pH Probe.”

In emailed comments to Reuters Health, he noted that many articles have shown MII-pH to be superior to simple pH monitoring. “The detection and description of reflux events and the ability of the test to associate reflux with other symptoms is far better accomplished by MII-pH than pH-metry alone.”

So, should pH monitoring be abandoned? “pH-metry isn’t completely useless, but it has serious limitations,” Dr. Putnam said.

“Consequently, one of the questions I raised in the editorial was whether anyone who has pH-metry available but not MII-pH should be using the results of pH-metry to manage patients,” he continued. “Patients who require evaluation for reflux and are candidates to undergo one of these tests should be informed that the better test might not be available in their home institution. I have serious concerns about initiating therapy for reflux based on the results of pH-metry alone.”

Dr. Putnam added, “Furthermore, escalating therapy to include surgery (fundoplication) for what seems to be recalcitrant reflux based on symptoms must be done on the basis of thorough evaluation and not these tests alone.”

J Pediatr 2010