Application and clinical significance of 24-hour multichannel intraluminal impedance-pH monitoring in gastroesophageal reflux disease

Objective To investigate the application and clinical significance of 24-hour multichannel intraaluminal impedance-pH (MII-pH) monitoring in gastroesophageal reflux disease (GERD).Methods Fiftythree patients with GERD were enrolled in this study according to the Montreal consensus (consulting for twice reflux a week or above) from July 2011 to June 2012.Patients were divided into erosive esophagitis (EE,n =25)group and non-erosive reflux disease (NERD,n =28) group after endoscopy and MII-pH monitoring.Fifteen healthy volunteers were recruited as the normal controls.The change of pH and MII-pH parameters were compared among the three groups and the significance of the change was investigated.Results Twenty-four-hour pH monitoring showed that all the acid reflux events in the EE and the NERD groups were significantly higher than those in the control group (P ＜ 0.05).MII-pH monitoring showed that the frequencies of total reflux,acid reflux,weakly acidic reflux and percentage of acid reflux in the GERD group were higher than in the control group (total reflux:83 (54,118) vs.62 (44,111) vs.42 (20,70),P =0.003 ; acid reflux:45 (25,79) vs.22 (11,45) vs.3(1,10),P =0.000 ;weakly acidic reflux:36(18,47) vs.43(21,82) vs.23(11,43),P =0.001 ;percentage of acid reflux:53％ (37％,81％) vs.32％ (13％,48％) vs.11％ (1％,23％),P =0.002).The frequency and percentage of acid reflux in the EE group were higher than those in the NERD group (P =0.000)The percentage of weakly acidic reflux in the NERD group was higher than in the EE group (66％ (43％,79％) vs.46％ (21％,57％),P ＜0.01).The frequencies of liquid reflux and mixed reflux in the GERD groups were higher than those in the control group (22 (12,40) vs.18 (12,26) vs.9 (4,18) ; 54 (39,79) vs.42 (25,77) vs.29(14,48) ;P ＜0.01).The frequency of gas reflux in the control group was higher than in the GERD group (86(56,207) vs.31 (14,62) vs.34 (15,119),P ＜ 0.01).The frequency and percentage of proximal reflux in the GERD group were significantly higher than in the control group (28(18,41) vs.16(12,34) vs.3 (2,9) ; 33％ (22％,49％) vs.29％ (22％,35％) vs.11％ (6％,22％),P ＜ 0.001).The percentage of symptom positive index in patients with acid reflux,non-acidic reflux and total reflux in the EE group were 36.0％ (9/25),20.0％ (5/25) and 56.0％ (14/25) respectively which were higher than in the NERD group (21.4％ (6/28),14.3％ (4/28) and 35.7％ (10/28)).Conclusion MII-pH monitoring can detect more reflux events.Acid reflux plays an important role in GERD.The detective rate of GERD will be elevated when combined with MII-pH monitoring in the diagnosis.MII-pH monitoring has a distinct advantage in diagnosing GERD. Key words: Gastroesophageal reflux disease;  Erosive esophagitis;  Non-erosive reflux disease; Multichannel intraluminal impedance-pH monitoring