Ambulatory esophageal pH testing

Over a 30-month period, 867 esophageal pH studies were conducted in a Canadian teaching hospital; of these, 315 tests were recorded in patients who were first-time referrals having no chest or upper gastrointestinal surgery and taking no medication that would affect the results. Patients were referred by gastroenterologists, general surgeons, ENT surgeons, thoracic surgeons, and a miscellaneous group. Patients were classified based on: pH results abnormal=% total time pH<4.0 (ie, >6.0%)], manometry (abnormal=LES resting pressure<5 mm Hg and/or abnormal peristalsis), and gender. Fifty-one percent (162/315) of the patient records demonstrated abnormal reflux. Intergroup comparisons of severity of reflux using two-way analysis of variance demonstrated no significant differences (P=0.13). In the 162 patients who refluxed, 70% (N=108) had normal motility studies; however, when the severity of reflux was compared, patients with abnormal motility (N=54) demonstrated significantly more severe reflux (19.8±12.8 vs 16.2±11.3)P=0.02. In those patients with abnormal manometry, no significant differences (P=0.44) in the severity of reflux were found among those with abnormal peristalsis (N=27), low resting pressure (N=17), or a combination of aperistalsis and low LES pressure (N=10). Symptomatic patients with reflux (N=107) demonstrated a significantly greater percent time pH<4.0 than those with asymptomatic reflux (N=55); 18.1±11.5% vs 16.2±12.7%,P=0.04. When the severity of reflux by gender was compared, no significant differences were found 18.3±11.9 (male)N=91 vs 16.2±11.9 (female)N=71,P=0.11]. The results from this study show that: (1) esophageal pH testing is important in subspecialties other than gastroenterology and that the clinical yield is high in all referring groups, (2) esophageal pH testing and manometry are complimentary tests, but that reflux occurs commonly in association with normal manometry, (3) asymptomatic reflux was found in 34% of the patients with abnormal reflux scores, and (4) the severity of reflux in male and female patients is similar.