Abstracts
1999 Digestive Disease Week

# 2112 MECHANISMS OF RESPIRATORY SYMPTOMS IN PATIENTS WITH GERD: IMPLICATIONS OF DUAL PROBE PH MONITORING
David James Bowrey, J H Peters, O L Gastal, L F Sillin, Cedric G Bremner, J Theisen, J A Hagen, P F Crookes, S R DeMeester, T R DeMeester, Univ of Southern CA, Los Angeles, CA

Introduction: The etiology of respiratory symptoms in patients with gastroesophageal reflux disease is controversial, both reflex- and reflux-mediated mechanisms have been proposed. The aim of this study was to determine the patterns of acid exposure in the proximal and distal esophagus of patients with respiratory symptoms and GERD.
Methods: 65 patients with respiratory symptoms and suspected GERD underwent stationary esophageal manometry followed by combined proximal (1 cm below UES) and distal (5 cm above LES) 24 hr esophageal pH monitoring. Ineffective motility was defined as 30% or more distal esophageal contraction amplitudes <30 mmHg. Pathological acid exposure was defined by a total time pH<4 of >4% for the distal esophagus and a total time pH<4 of > 1% for the proximal esophagus.
Results: Pathological esophageal acid exposure was detected in 36 patients (55%). Nineteen of these patients (53%) had both proximal and distal reflux, 13 patients (36%) had distal reflux only and 4 patients (11%) had proximal reflux only. Proximal reflux episodes were preceded by distal reflux episodes on >99% of occasions. Patients with abnormal proximal esophageal acid exposure were characterized by low LES pressures and a high prevalence of ineffective motility (table). Proximal esophageal acid exposure was significantly greater in patients with ineffective motility, median total time pH<4 2.2% (IQR 1.0-7.7) compared to patients without ineffective motility, median total time pH<4 0.1% (IQR 0-2.0), p<0.05. There was no significant difference in the distal esophageal acid exposure between patients with and without ineffective motility.
Conclusions: 55% of patients with unexplained respiratory symptoms had documented esophageal pH study abnormalities. Six percent of patients had abnormal proximal reflux only. Patients with proximal reflex were characterized by low LES pressures and a high prevalence of ineffective motility suggesting that symptoms in these patients are accounted for by a reflux-mediated mechanism. These findings may have implications for the selection of patients for surgical therapy.

	No reflux (n=29)	Distal reflux only (n=13)	Proximal reflux (n=23)
Proximal pH	-ve	-ve	+ve
Distal pH	-ve	+ve	-ve or +ve
LESP (mmHg) Defective LES (%)	12.4 (7.7-21.4) 3 4%	11.6 (6.1-16.4) 54%	4.8 (3.2-12.0)* 65%**
Contr. amplitude (mmHg)	94	93	41**
Ineffective motility (%)	12%	8%	35%**
*p<0.05 vs. no reflux & p=0.05 vs. distal reflux, **p<0.05 vs. no reflux, *** p<0.05 vs. both groups

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