INCLUSION OF SUPINE PERIOD IN SHORT-DURATION PH MONITORING IS ESSENTIAL IN DIAGNOSIS OF GASTROESOPHAGEAL REFLUX DISEASE

Prolonged esophageal pH monitoring is the most accurate method for det ecting abnormal gastroesophageal reflux (GER) in patients with gastroe sophageal reflux disease (GERD). However, some investigators have foun d that short-duration postprandial pH monitoring in the upright positi on is also useful, while others have failed to find such results. Ther efore, we have compared a 6-hr period of pH monitoring (3-hr postprand ial period after daytime meal and 3-hr supine period) with a total 24- hr period in detecting abnormal gastroesophageal reflux. Sixty-five pa tients (44 men, mean age 41.3 years) with GERD and 16 healthy voluntee rs (11 men, mean age 34.3 years) underwent 24-hr pH monitoring accordi ng to a standard protocol. Various reflux parameters during 24-hr pH m onitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symp toms of GERD (sensitivity 86.2%). These patients could be further divi ded into upright (N = 18), supine (N = 15), and combined (N = 23) refl uxers, depending on the posture in which abnormal reflux occurred. Eso phageal pH monitoring during the 3-hr postprandial upright period show ed abnormal reflux in only 35 patients (sensitivity 53.8%; P < 0.00005 , compared with the 24-hr pH monitoring period). Abnormal GER was iden tified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supi ne refluxers, as well as in two of nine patients with normal 24-hr pH- metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients; P = NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supi ne refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlat ed significantly with severity of esophagitis only during the total an d supine periods of both the 24- and 6-hr periods and not during the u pright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods onl y. We conclude that 3-hr postprandial pH monitoring, as has been conve ntionally practiced, is not appropriate in the detection of abnormal G ER; inclusion of a supine period in the short-duration pH monitoring s chedule increases the detection of pathological reflux. We therefore r ecommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflux was the most im portant factor in the development of esophagitis.