Clinical Studies with the Dx–pH Measurement System™

Restech's Dx–System is the subject of over 20 clinical trials currently in progress across a broad spectrum of medical disciplines.

University of Southern California
Dr. Tom DeMeester’s group at USC’s Advanced Esophageal Function Laboratory has completed their normative data trial and presented the results at the 2008 Digestive Disease Week conference in San Diego. The aim of this study was to determine normal values for pharyngeal acid exposure using the Dx–pH Probe. The study population consisted of 55 asymptomatic volunteers who all underwent 24 hour pH monitoring in the esophagus and the oropharynx simultaneously.

The study abstract and presentation, authored by Dr. Shahin Ayazi, report that in the upright period, 5.5 is the best pH threshold to define abnormal acid exposure, while pharyngeal acid exposure is considerably higher in the supine period and a lower threshold is necessary. For the supine period, pH <5.0 would maximize sensitivity and pH < 4.5 would maximize specificity. From the data set, a new diagnostic score, the “RYAN Score” was developed, and has been incorporated into Restech’s upcoming version of pH data analysis software, DataView Lite. The values obtained can now be used to determine if patients with laryngeal or respiratory symptoms have abnormal pharyngeal acid exposure.
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Emory University Voice Center
At the year’s Combined Otolaryngology Spring Meetings, Emory University’s Voice Center presented their research “Comparison of an Oropharyngeal pH Probe and a Standard Dual pH Probe for Diagnosis of Laryngopharyngeal Reflux.” Dr. Justin Golub described the limitations of the non-specific diagnostic methods of Laryngopharyngeal reflux (LPR), and how the Dx–pH Sensor shows promise in overcoming the current difficulty in identifying LRP. Comparing the Dx–pH Sensor to the current “gold-standard,” Emory’s study concluded that the information obtained with the Dx–pH Probe correlates closely and that the Dx–pH Probe may be useful for screening patients and providing objective diagnostic data.

Medical College of Georgia
Director of the Center for Voice and Swallowing Disorders Dr. Greg Postma, and Dr. Robert Schade, Head of the Department of Gastroenterology, studied twenty asymptomatic volunteers with simultaneous standard esophageal-hypopharyngeal monitoring and Restech’s Oropharyngeal Dx–pH Probe. The presentation, delivered by Dr. Neil Chheda, concluded that “the Dx–pH Probe represents a safe, convenient, comfortable tool that can be safely used to measure EER (Extraesophageal Reflux). Advances in technology allow its placement in the oropharynx to detect both liquid and gas events.” Normative data was presented as well, and additional studies will be performed to further determine clinical implications.

David Malis, MD, Pediatric Otolaryngology
Pediatric Otolaryngology Diagnosis of Laryngopharyngeal Reflux is especially important in children. In the past it has been very difficult due to unreliable technology and the invasive nature of diagnostic tests. Dr. David Malis (Melbourne, FL) has been using the Dx–System in his Pediatric Otolaryngology practice for over a year now, and has completed more than one-hundred Dx–pH studies. Dr. Malis presented a case report on ten of these patients. A pH probe was placed in each child, and the 24 hour study was well tolerated in each of them. Each child had LPR activity as defined by numerous drops of 10% or greater from a running baseline and a twelve-week course of Proton Pump Inhibitors (PPIs) was prescribed. At follow-up after 12 weeks, the response to therapy determined by repeat pH probe testing (8 children) or clinically (2 children). Dr. Malis reports that his preliminary experience with the Restech Dx-System has been encouraging in identifying children with LPR, and has helped him in prescribing more appropriate medical treatment for his patients. Download Presentation >>

Vanderbilt University
The Digestive Disease Center at Vanderbilt University Medical Center, headed by Dr. Michael Vaezi, presented their findings in asymptomatic volunteers last October at the American College of Gastroenterology. The ADHERE Study (Application of the Dx–pH Catheters in the Evaluation of Patients without Gastroesophageal Reflux Disease) concluded that “Normative values for the new Dx–pH catheter compare favorably to the accepted gold standard pH monitoring device.” Download Study >>

Gregory Wiener, MD
gave an oral presentation on his research with the Dx-System at DDW 2006. Review findings >>

Chris Landon, MD
has performed several pediatric case studies with the Dx-System. Review Cases >>

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