TY - JOUR
T1 - Normal values and regional differences in oesophageal impedance-pH metrics
T2 - a consensus analysis of impedance-pH studies from around the world
AU - Sifrim, Daniel
AU - Roman, Sabine
AU - Savarino, Edoardo
AU - Bor, Serhat
AU - Bredenoord, Albert J
AU - Castell, Donald
AU - Cicala, Michele
AU - de Bortoli, Nicola
AU - Frazzoni, Marzio
AU - Gonlachanvit, Sutep
AU - Iwakiri, Katsuhiko
AU - Kawamura, Osamu
AU - Krarup, Anne
AU - Lee, Yeong Yeh
AU - Soon Ngiu, Chai
AU - Ndebia, Eugene
AU - Patcharatraku, Tanisa
AU - Pauwels, Ans
AU - Pérez de la Serna, Julio
AU - Ramos, Rosa
AU - Remes-Troche, Jose Maria
AU - Ribolsi, Mentore
AU - Sammon, Alastair
AU - Simren, Magnus
AU - Tack, Jan
AU - Tutuian, Radu
AU - Valdovinos, Miguel
AU - Xiao, Yinglian
AU - Zerbib, Frank
AU - Gyawali, C Prakash
N1 - © Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.
PY - 2021/7/12
Y1 - 2021/7/12
N2 - OBJECTIVE: Limitations of existing impedance-pH thresholds include small sample size of normative studies, inclusion of artefactual pH drops and incorrect identification of impedance reflux events. We aimed to obtain new impedance-pH thresholds from expert consensus analysis of tracings from a large number of healthy subjects.DESIGN: Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI).RESULTS: Consensus analysis was performed in 391 tracings (age 32.7 years, range 18-71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie.CONCLUSION: Normal impedance-pH monitoring thresholds have regional and system-related differences. Clinical interpretation needs to use normal thresholds valid for the system used and world region, following careful editing of the tracings.
AB - OBJECTIVE: Limitations of existing impedance-pH thresholds include small sample size of normative studies, inclusion of artefactual pH drops and incorrect identification of impedance reflux events. We aimed to obtain new impedance-pH thresholds from expert consensus analysis of tracings from a large number of healthy subjects.DESIGN: Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI).RESULTS: Consensus analysis was performed in 391 tracings (age 32.7 years, range 18-71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie.CONCLUSION: Normal impedance-pH monitoring thresholds have regional and system-related differences. Clinical interpretation needs to use normal thresholds valid for the system used and world region, following careful editing of the tracings.
KW - acid exposure time
KW - impedance-pH monitoring
KW - post reflux swallow-induced peristaltic wave
KW - reflux episodes
UR - http://www.scopus.com/inward/record.url?scp=85095114409&partnerID=8YFLogxK
U2 - 10.1136/gutjnl-2020-322627
DO - 10.1136/gutjnl-2020-322627
M3 - Journal article
C2 - 33037054
SN - 0017-5749
VL - 70
SP - 1441
EP - 1449
JO - Gut
JF - Gut
IS - 8
ER -