Korean J Gastroenterol.  2025 Jul;85(3):274-279. 10.4166/kjg.2025.069.

Clinical Significance of the Mean Nocturnal Baseline Impedance and Post-Reflux Swallow-Induced Peristaltic Wave Index in the Diagnosis of Gastroesophageal Reflux Disease

• Lee JY

• KMID: 2570610
• DOI: http://doi.org/10.4166/kjg.2025.069

Abstract

Gastroesophageal reflux disease (GERD) is a common condition characterized by the reflux of gastric contents into the esophagus, often leading to troublesome symptoms or complications. Although the acid exposure time (AET) has long been used as a key diagnostic marker, it may be insufficient in certain clinical situations, particularly in patients with borderline AET. Recently, two novel impedance-based parameters have emerged as useful adjuncts in the diagnostic evaluation of GERD: mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW-I). These metrics reflect the esophageal mucosal integrity and chemical clearance, offering physiologically relevant insights beyond AET. Studies suggest that a low MNBI (<1,500 Ω) and PSPW-I (<61%) are associated with pathological reflux and favorable response to proton pump inhibitors. Moreover, the combined use of MNBI and PSPW-I may enhance diagnostic accuracy and aid in predicting the therapeutic outcomes. This review summarizes the physiological background, diagnostic thresholds, and clinical implications of MNBI and PSPW-I based on the current literature and highlights their potential role in GERD diagnosis and management. Nevertheless, future standardization and automation may further improve their clinical utility.

Keyword

Gastroesophageal reflux; Impedance; Esophageal pH monitoring; Peristalsis