Esophageal multichannel intraluminal impedance testing
- Radu Tutuian, MD
Radu Tutuian, MD
- Associate Professor, Gastroenterology
- University of Bern, Switzerland
- Donald O Castell, MD
Donald O Castell, MD
- AGA Peer Reviewer
- Professor of Medicine
- Director, Esophageal Disorders Program
- Medical University of South Carolina
Multichannel intraluminal impedance (MII) is a catheter-based method to detect intraluminal bolus movement within the esophagus. MII is performed in combination with manometry or pH testing. When combined with manometry, it provides information on the functional (ie, bolus transit) component of manometrically detected contractions. When combined with pH testing, it allows for the detection of gastroesophageal reflux independent of pH (ie, both acid and non-acid reflux).
This topic will review the principles, technique, and results of esophageal MII testing, and their clinical implications. Motility testing and high-resolution esophageal manometry are discussed in detail, separately. (See "High resolution manometry" and "Motility testing: When does it help?" and "Esophageal motility disorders: Clinical manifestations, diagnosis, and management".)
PRINCIPLES OF IMPEDANCE TESTING
Impedance testing is based on the measurement of changes in resistance to alternating electrical current when a bolus passes by a pair of metallic rings mounted on a catheter. In an empty tubular organ such as the esophagus, the electrical current between the two rings is conducted by the few ions present in and on the mucosa. Liquid-containing boluses with an increased number of ions have a higher conductivity and, when entering the impedance-measuring segment, will lower the impedance to a nadir value. The impedance stays at its nadir as long as the bolus is present in the segment, returning to baseline once the bolus is cleared by a contraction. The contraction produces a slight increase in impedance above the baseline due to a decrease in luminal cross-section. Gas passing transiently by the impedance-measuring segments will produce a rapid and high (usually >3000 Ohms) rise in the impedance since it has poor electrical conductance.
Measuring impedance at multiple sites (multichannel) allows for determination of the direction of bolus movement based upon temporal differences in bolus entry and exit. Bolus entries progressing from proximal to distal indicate antegrade bolus movement, while bolus entries progressing from distal to proximal indicate retrograde bolus movement (waveform 1).
COMBINED MULTICHANNEL INTRALUMINAL IMPEDANCE AND MANOMETRY
Standard manometry does not demonstrate whether a contraction results in actual bolus passage. Combined multichannel intraluminal impedance with esophageal manometry (MII-EM) is a test of esophageal function as it provides information about both pressures and bolus transit within the esophagus.
- Sifrim D, Dupont L, Blondeau K, et al. Weakly acidic reflux in patients with chronic unexplained cough during 24 hour pressure, pH, and impedance monitoring. Gut 2005; 54:449.
- Koya DL, Agrawal A, Freeman JE, Castell DO. Impedance detected abnormal bolus transit in patients with normal esophageal manometry. Sensitive indicator of esophageal functional abnormality? Dis Esophagus 2008; 21:563.
- Clayton SB, Rife C, Kalbfleisch JH, Castell DO. Viscous impedance is an important indicator of abnormal esophageal motility. Neurogastroenterol Motil 2013; 25:563.
- Tutuian R, Vela MF, Balaji NS, et al. Esophageal function testing with combined multichannel intraluminal impedance and manometry: multicenter study in healthy volunteers. Clin Gastroenterol Hepatol 2003; 1:174.
- Yigit T, Quiroga E, Oelschlager B. Multichannel intraluminal impedance for the assessment of post-fundoplication dysphagia. Dis Esophagus 2006; 19:382.
- Tutuian R, Castell DO. Combined multichannel intraluminal impedance and manometry clarifies esophageal function abnormalities: study in 350 patients. Am J Gastroenterol 2004; 99:1011.
- Conchillo JM, Nguyen NQ, Samsom M, et al. Multichannel intraluminal impedance monitoring in the evaluation of patients with non-obstructive Dysphagia. Am J Gastroenterol 2005; 100:2624.
- Tutuian R, Castell DO. Clarification of the esophageal function defect in patients with manometric ineffective esophageal motility: studies using combined impedance-manometry. Clin Gastroenterol Hepatol 2004; 2:230.
- Tutuian R, Mainie I, Agrawal A, et al. Symptom and function heterogenicity among patients with distal esophageal spasm: studies using combined impedance-manometry. Am J Gastroenterol 2006; 101:464.
- Hirano I, Richter JE, Practice Parameters Committee of the American College of Gastroenterology. ACG practice guidelines: esophageal reflux testing. Am J Gastroenterol 2007; 102:668.
- Ford CN. Evaluation and management of laryngopharyngeal reflux. JAMA 2005; 294:1534.
- Oelschlager BK, Quiroga E, Isch JA, Cuenca-Abente F. Gastroesophageal and pharyngeal reflux detection using impedance and 24-hour pH monitoring in asymptomatic subjects: defining the normal environment. J Gastrointest Surg 2006; 10:54.
- Tutuian R, Mainie I, Agrawal A, et al. Nonacid reflux in patients with chronic cough on acid-suppressive therapy. Chest 2006; 130:386.
- Pritchett JM, Aslam M, Slaughter JC, et al. Efficacy of esophageal impedance/pH monitoring in patients with refractory gastroesophageal reflux disease, on and off therapy. Clin Gastroenterol Hepatol 2009; 7:743.
- Sifrim D, Castell D, Dent J, Kahrilas PJ. Gastro-oesophageal reflux monitoring: review and consensus report on detection and definitions of acid, non-acid, and gas reflux. Gut 2004; 53:1024.
- Shay S, Tutuian R, Sifrim D, et al. Twenty-four hour ambulatory simultaneous impedance and pH monitoring: a multicenter report of normal values from 60 healthy volunteers. Am J Gastroenterol 2004; 99:1037.
- Vela MF, Camacho-Lobato L, Srinivasan R, et al. Simultaneous intraesophageal impedance and pH measurement of acid and nonacid gastroesophageal reflux: effect of omeprazole. Gastroenterology 2001; 120:1599.
- Tutuian, R, Mainie, I, Agrawal, A, et al. Normal values for ambulatory 24-h combined impedance-pH monitoring on acid suppressive therapy. Gastroenterology 2006; 130 Suppl 2:A171.
- Zerbib F, Roman S, Bruley Des Varannes S, et al. Normal values of pharyngeal and esophageal 24-hour pH impedance in individuals on and off therapy and interobserver reproducibility. Clin Gastroenterol Hepatol 2013; 11:366.
- Weusten BL, Roelofs JM, Akkermans LM, et al. The symptom-association probability: an improved method for symptom analysis of 24-hour esophageal pH data. Gastroenterology 1994; 107:1741.
- Bredenoord AJ, Weusten BL, Timmer R, Smout AJ. Reproducibility of multichannel intraluminal electrical impedance monitoring of gastroesophageal reflux. Am J Gastroenterol 2005; 100:265.
- Mainie I, Tutuian R, Shay S, et al. Acid and non-acid reflux in patients with persistent symptoms despite acid suppressive therapy: a multicentre study using combined ambulatory impedance-pH monitoring. Gut 2006; 55:1398.
- Zerbib F, Roman S, Ropert A, et al. Esophageal pH-impedance monitoring and symptom analysis in GERD: a study in patients off and on therapy. Am J Gastroenterol 2006; 101:1956.
- Mainie I, Tutuian R, Agrawal A, et al. Combined multichannel intraluminal impedance-pH monitoring to select patients with persistent gastro-oesophageal reflux for laparoscopic Nissen fundoplication. Br J Surg 2006; 93:1483.
- Sharma N, Agrawal A, Freeman J, et al. An analysis of persistent symptoms in acid-suppressed patients undergoing impedance-pH monitoring. Clin Gastroenterol Hepatol 2008; 6:521.
- Kline MM, Ewing M, Simpson N, Laine L. The utility of intraluminal impedance in patients with gastroesophageal reflux disease-like symptoms but normal endoscopy and 24-hour pH testing. Clin Gastroenterol Hepatol 2008; 6:880.
- Tutuian R, Vela MF, Hill EG, et al. Characteristics of symptomatic reflux episodes on Acid suppressive therapy. Am J Gastroenterol 2008; 103:1090.
- Savarino E, Zentilin P, Tutuian R, et al. The role of nonacid reflux in NERD: lessons learned from impedance-pH monitoring in 150 patients off therapy. Am J Gastroenterol 2008; 103:2685.
- ASGE Technology Committee, Wang A, Pleskow DK, et al. Esophageal function testing. Gastrointest Endosc 2012; 76:231.
- PRINCIPLES OF IMPEDANCE TESTING
- COMBINED MULTICHANNEL INTRALUMINAL IMPEDANCE AND MANOMETRY
- Patient protocol
- Impedance results parameters
- Clinical application
- COMBINED MULTICHANNEL INTRALUMINAL IMPEDANCE AND PH
- Patient protocol
- - Testing on or off proton pump inhibitors
- Impedance-pH results parameters
- - Refluxate composition
- - Proximal extent of reflux
- - Number of acid and non-acid reflux episodes
- - Refluxate contact time
- - Refluxate clearance time
- - Reflux pH
- Interpretation of results
- - Reference values
- - Symptom correlation measures
- Clinical application
- COMPLICATIONS AND CONTRAINDICATIONS
- SUMMARY AND RECOMMENDATIONS