Background: Vagal reflex initiated by esophageal stimulation and microaspiration can cause chronic cough in patients with gastroesophageal reflux disease (GERD). By raising intraabdominal pressure,cough can, in turn, predispose to GERD. The role of the upper esophageal sphincter (UES)in preventing esophagopharyngeal reflux during coughing is not well known. The aim of this study was to evaluate the UES response during coughing.
Methods: We studied 20 healthy young (10 women; age, 27 ± 5 years) and 15 healthy elderly(nine women; age, 73 ± 4 years) subjects. Hard and soft cough-induced pressure changes in the UES, distal esophagus, lower esophageal sphincter, and stomach were determined simultaneously using high-resolution manometry and concurrent acoustic cough recordings.
Results: Resting UES pressure was significantly higher in the young compared with the elderly subjects (42 ± 14 mm Hg vs 24 ± 9 mm Hg; P < .001). Cough induced a UES contractile response in all subjects. Despite lower UES resting pressures in the elderly subjects, the maximum UES pressure during cough was similar between the young and the elderly subjects (hard cough, 230 ± 107 mm Hg vs 278 ± 125 mm Hg, respectively; soft cough, 156 ± 85 mm Hg vs 164 ± 119 mm Hg, respectively; P not significant for both). The UES pressure increase over baseline during cough was significantly higher than that in the esophagus, lower esophageal sphincter, and stomach for both groups ( P < .001).
Conclusions: Cough induces a rise in UES pressure, and this response is preserved in elderly people. A cough-induced rise in UES pressure is significantly higher than that in the esophagus and stomach,thereby providing a barrier against retrograde entry of gastric contents into the pharynx.