accurately detects.docx

1、accurately detectsAm J Physiol Gastrointest Liver Physiol 283: G376-G383, 2002. Multichannel intraluminal impedance accurately detects fasting, recumbent reflux events and their clearing Steven S. Shay, Steven Bomeli, and Joel Richter Gastroenterology Service, Cleveland Clinic Foundation, Cleveland,

2、 Ohio 44195 ABSTRACT Multichannel intraluminal impedance (MII) is a new diagnostic test for gastroesophageal reflux disease (GERD). The objective of this report is to determine the accuracy of MII in detecting individual reflux events (REs) identified by pH probe and manometry, as well as their clea

3、ring in patients with severe GERD compared with normal volunteers. Ten severe GERD patients and 10normal volunteers underwent simultaneous manometry 7 sites: gastric, lower esophageal sphincter, esophagus (4), pharynx, pH, and MII (6sites in esophagus) for 15min in the left and right recumbent postu

4、re while fasting. We found that patients had 30-fold more REs than normal volunteers (4111vs. 1.30.4), and 95% of all REs were detected by MII. An average 15-fold fall in impedance with liquid and fivefold rise with gas made REs and their composition easy to detect with MII. In the right recumbent p

5、osture, nearly all REs detected by MII were liquid (98%, 98/100). In contrast, all 283REs detected by MII in the left recumbent posture were gas. Nearly all REs detected by MII were cleared (98%, 368/374). Mean acid clearing time was threefold longer (47s) than clearing time by either manometry (15s

6、) or MII (13s), primarily due to acid rereflux, i.e., additional acid REs during acid clearing. We conclude that MII is accurate in detecting REs identified by manometry and/or pH probe, their composition, and their clearing. pH monitoring; common cavities; gastroesophageal reflux disease INTRODUCTI

7、ON MULTICHANNEL INTRALUMINAL impedance (MII) is a new method for gastroesophageal reflux disease (GERD) patients that assesses transit based on changes in resistance to current flow between adjacent electrodes when a bolus passes between them (2). MII detects gastroesophageal reflux events (REs) whe

8、n aboral flow occurs across two or more distal electrodes in the esophagus, and MII can also assess whether the composition of the refluxed gastric contents is gas, liquid, or mixed. Three recent reports (6, 7, 9) examined the promising role of MII combined with pH in detecting acid and nonacid REs.

9、 Two reports compared GERD patients with normals, one utilizing postprandial simultaneous manometry, pH, and MII in the upright posture, and the other ambulatory 24-h MII-pH. Both reports found that total REs were similar in normals and GERD patients, although acid REs made up a greater proportion o

10、f REs in GERD patients. In addition, mixed REs were more common than liquid-only REs (6, 7). In another report of combined MII-pH after a refluxogenic meal in GERD patients, omeprazole decreased acid REs; however, total REs were unchanged, because nonacid REs increased (9). In these reports, mean RE

11、 frequency was 10.5/hr (6) and 10/hr (9) in the short-term studies but only 46per 24h in the 24-h study (7). Present reflux tests have fundamental differences in the measurement parameter analyzed. The pH probe measures acid concentration in a volume of unknown amount. Thus when gastric contents wit

12、h a pH of 2refluxes into the esophagus, a gallon of refluxant with pH 2looks the same to the pH probe as an ounce of refluxant with pH 2.Conversely, the common cavity (detected by manometry) cant assess concentration of any chemical component, especially acid. Instead, the common cavity detects when

13、 enough volume of gastric contents enters the esophagus to raise intraesophageal pressure to that of intragastric pressure. However, that threshold volume and the final refluxed volume is unknown. Measurement characteristics of REs detected by impedance are unknown. The purpose of this report is fou

14、rfold: 1) to validate the accuracy of MII in detecting individual REs in the most challenging situation, which is maximizing RE frequency by studying only patients with severe GERD and maximizing RE detection by combining manometry and pH monitoring; 2) to compare clearing of REs by pH, MII, and man

15、ometry; 3) to compare refluxant composition in different postures; and 4) to assess the measurement characteristics of impedance. MATERIALS AND METHODS Study Population Ten symptomatic patients (age 534; 5males, 5females) with severe GERD were selected on the basis of two criteria: 1) moderate or se

16、vere GERD by endoscopy thin erosions (n=4); confluent ulcerations (n=2); long-segment Barretts esophagus (n=4); and 2) 10 common cavities detected during standard esophageal manometry. Other findings of severe GERD were present on barium esophagram (7/7 with both reflux and hiatal hernia) and 24-h p

17、H (8/8 with abnormal acid exposure; %time pH 4/time monitored: total=258%; upright=217%; recumbent=3011%). Ten normal volunteers (age 354; 6males, 4females) were studied for comparison. Study Design All subjects underwent simultaneous manometry, pH, and MII in the fasting left and right recumbent po

18、stures. Some severe GERD patients were also monitored after a nonrefluxogenic meal. Subjects were studied in accordance with protocol 3565,which was approved by the Institutional Review Board of the Cleveland Clinic Foundation on March 15,2000.Written informed consent was obtained. Simultaneous esop

19、hageal manometry, MII, and pH monitoring. A multichannel esophageal manometry catheter with a 7-cm distal sleeve (DentSleeve) was passed through the nose and into the esophagus so that it straddled the lower esophageal sphincter (LES). A 2.13-mm MII-pH catheter (model Z-TC; Sandhill) was passed adja

20、cent to the manometry catheter such that the perfused side ports and MII sites had the configuration shown in Fig. 1. Swallows were recorded by an air-perfused hypopharyngeal port. All data were recorded simultaneously by the Sandhill Insight data-acquisition system for subsequent analysis. View lar

21、ger version (26K): in this window in a new window Fig. 1. Catheter configuration, as well as locations of perfusion ports for manometry, electrode pair sites for multichannel intraluminal impedance (MII), and pH probe. LES, lower esophageal sphincter. Continuous fasting recordings were obtained for

22、15min on the left and then the right recumbent postures. Severe GERD patients with fewer than five liquid REs in the right recumbent posture by MII were then given 8oz of yogurt (Dannon; lemon flavor) and 8oz of water, and monitored for an additional 15min on their right side. Definition of REs and

23、clearing. The pH probe defined a RE traditionally (pH-RE); i.e., a fall in pH from 4 to 4, and acid clearing time (ACT) of seconds until pH 4was again achieved. Manometry defined a RE as when a common cavity occurred. A common cavity was defined as an increase in intraesophageal pressure from gastro

24、esophageal pressure equilibration that was not associated with increased intraesophageal pressure from a swallow, dysmotility, or movement. Its duration was seconds until the peristaltic contraction decreased intraesophageal pressure to baseline. Acid rereflux was defined as a common cavity while pH

25、 was already 4, i.e., rereflux of acidified gastric contents into the esophagus before successful acid clearing after a traditional pH-RE (Figs. 2, 3, and 4). View larger version (46K): in this window in a new window Fig. 2. Four episodes of acid rereflux over a low basal LES pressure (LESp) are sho

26、wn (see vertical lines 1-4) during simultaneous manometry, pH, and MII. Ten seconds into the tracing, a pH fall of 1unit occurs, whereas pH is 50% from baseline (to 0in 2leads); and 2) a common cavity occurs simultaneously with the onset of the MII-RE. Acid rereflux similar to above occurs on 3other

27、 occasions, although 2have a pH fall 50% from baseline simultaneously, reaching 7,000sometime during the RE in all sites; and 2) in the manometry ports, a common cavity is detected by the increase in intraesophageal pressure. Esophageal pH is 6 during the RE. The other 4gas-only REs are similar, alt

28、hough the 2nd does not extend to the proximal impedance site. All MII-REs and common cavities clear concurrently to their original baselines denoting simultaneous clearance after a secondary (n=4) or primary (n=1) esophageal contraction. View larger version (27K): in this window in a new window Fig.

29、 4. The 4most common RE types based on changes in pH and composition of refluxed gastric contents: traditional acid RE liquid by impedance, acid rereflux liquid by impedance, nonacid reflux gas by impedance, and nonacid reflux liquid by impedance. Mean values are displayed for changes in pH, ohms, and mmHg for all REs in the RE type shown. Acid rereflux is reflux of acidified liq