Wireless 24, 48, and 96 Hour or Impedance or Oropharyngeal Prolonged pH Monitoring: Which Test, When, and Why for GERD?
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Purpose of Review
pH monitoring technologies are routinely utilized in practice to further evaluate symptoms of gastro-esophageal reflux disease and laryngopharyngeal reflux (LPR). This is a review of the recent literature of the available pH monitoring technology and creates an algorithm in the diagnostic work up of a patient with GERD or LPR.
The catheter-free wireless pH monitor traditionally collects data for 48 h. Recent studies have found that extending to 96 h can be helpful in patients with conflicting results on the first 2 days of the study. In addition, 96 h can allow for testing both on and off of PPI therapy. The oropharyngeal monitoring device is a newer technology that is designed to aid in the diagnoses of LPR. There are limitations with this technology as there is no universal abnormal cutoff and some studies have suggested a poor correlation between multichannel intraluminal impedance-pH (MII-pH) and the oropharyngeal monitoring device. MII-pH has recently developed two additional parameters, the measurement of three 10-min nighttime periods and the post-reflux swallow-induced peristaltic wave (PSPW) index, both of which may increase accuracy of testing.
Each of these technologies can provide unique data regarding acid reflux exposure in the esophagus and oropharynx. The wireless pH monitor performed off of PPI therapy can help to establish or exclude the diagnosis of GERD. For those patients with refractory symptoms on PPI, MII-pH study can be performed while on therapy and provides data regarding the response to treatment. Oropharyngeal pH monitoring is being utilized in some practices to aid in diagnosis of LPR, but the scientific validity is controversial.
KeywordsWireless pH monitor Oropharyngeal pH monitor Impedance pH test Weak acid reflux Gastroesophageal reflux disease
Compliance with Ethical Standards
Conflict of Interest
Soojong Chae and Joel Richter declare no conflict of interest. Dr. Richter is the Editor in Chief of Current Gastroenterology Reports, but this paper was reviewed by Section Editor Satish Rao.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
- 5.• Richter JE, Pandolfino JE, Vela MF, et al. Utilization of wireless pH monitoring technology: A summary of the proceedings of the Esophageal Diagnostic Working Group. Dis Esophagus. 2013;26:755–65 An evidence-based summary of the wireless pH monitoring capsule and provides an algorithm for patients with GERD not responding to medical therapy. CrossRefGoogle Scholar
- 9.• Patel R, Chae S, Kumar A, Richter JE. Sedation and afternoon placement of the 48-hr wireless ambulatory capsule results in more reflux on the first day. J Clinical Gastroenterol. 2017;51(7):594–8 In 225 patients, morning versus afternoon placement of wireless motility capsule were compared. The median DeMeester score was 15.3 for morning placement and 24.7 for afternoon placement. CrossRefGoogle Scholar
- 10.Patel R, Chae S, Jacobs J, Kumar A, Richter J. 96-hour esophageal pH monitoring: the tiebreaker for abnormal DeMeester score and symptom index. Gastroenterology. 2018;154(6):S-487–7.Google Scholar
- 16.Wiener GJ, Tsukashima R, Kelly C, Wolf E, Schmeltzer M, Bankert C, et al. Oropharyngeal pH monitoring for the detection of liquid and aerosolized supraesophageal gastric reflux. J Voice. 2009;23:498–504.Google Scholar
- 17.• Yadlapati R, Pandolfino JE, Lidder AK, Shabeeb N, et al. Oropharyngeal pH testing does not predict response to proton pump inhibitor therapy in patients with laryngeal symptoms. Am J Gastroenterol. 2016;111:1517–24 34 patients underwent video laryngoscopy and 24 h oropharyngeal pH monitoring followed by an 8- to 12-week trial of omeprazole 40 mg daily. Oropharyngeal acid exposure was no different between those who responded to PPI therapy, no response to PPI, and partial response to PPI. In secondary analysis, there was an inverse relation between PPI response and oropharyngeal acid exposure. CrossRefGoogle Scholar
- 22.•• Zerbid F, Roman S, Bruley Des Varannes S, et al. Normal values of pharyngeal and esophageal 24 hour impedance in individuals on and off therapy and interobserver reproducibility. Clin Gastroenterol Hepatol. 2013;11:366–72 Basis for normal values on and off PPIs from 46 healthy controls. Analysis of esophageal events were reproducible, but analyses of pharyngeal events was not. CrossRefGoogle Scholar
- 25.• Koop A, Francis DL, DeVault KR. Visual and automated computer analysis differ substantially in detection of acidic reflux in MII-pH monitoring. Clin Gastro Hepatol. 2018;16:979–80 The visual and automated computer analysis of 33 M11-pH studies agreed in only 78% of pH drops to < pH4. CrossRefGoogle Scholar
- 27.Kline MM, Ewing M, Simpson N et al. The utility of intraluminal impedance in patients with gastroesophageal reflux disease-like symptoms but normal endoscopy and 24 hour pH testing, Clin Gastroenterology Hepatology 2008; 6:880–889.Google Scholar
- 28.•• Patel A, Sayuk GS, Gyawali CP. Acid-based parameters on pH impedance testing predict symptom improvement with medical management better than impedance parameters. Am J Gastroenterol. 2014;109:836–44 Performing pH –impedance testing off PPIs best predicts response to antireflux therapy. Key predictors are acid exposure time and correlation between symptoms and reflux events detected by impedance. CrossRefGoogle Scholar
- 29.•• Francis DO, Goutte M, Slaughter JC, et al. Traditional reflux parameters and not impedance monitoring predict outcomes after fundoplication in extraesophageal reflux. Laryngoscope. 2011;121:1902–9 Based on over 100 patients going to surgery, the best predictions of success was % time pH > 10%, presence of heartburn/regurgitation and large hiatal hernia. Neither symptom correlation or impedance parameters were predictive. CrossRefGoogle Scholar
- 33.• Patel A, Wang D, Sainami N, et al. Distal mean nocturnal baseline impedance on pH impedance monitoring predicts reflux burden and symptomatic outcome in GERD. Aliment Pharmacol Ther. 2016;44:890–8 Distal esophageal means nocturnal baseline impedance negatively correlates with acid exposure time. When assessed off PPIs, this measure is independently predictive of symptomatic improvement following anti-reflux therapy. CrossRefGoogle Scholar
- 34.•• Frazzoni M, Savarino E, de Bortoli N, et al. Analyses of the post-reflux swallow-induced peristaltic wave index and nocturnal baseline impedance parameters increase the diagnostic yield of impedance-pH monitoring of patients with reflux disease. Clin Gastroenterol Hepatol. 2016;14:–40, 6 Study in 68 esophagitis and 221 NERD patients suggesting high diagnostic yield of nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index. Google Scholar