Responses to different levels of esophageal acidification during waking and sleep.

The purpose of this study was to assess the effect of hydrogen ion concentration of intraesophageal infusions during sleep on acid clearance time and latency to swallow and arousal responses from sleep. We studied 10 normal volunteers during sleep via polysomnography and concomitant esophageal pH monitoring. Sleep prolonged the acid clearance time of both pH 3.0 and 1.2. Swallow and arousal latencies were both progressively decreased with decreasing pH of the infusate (P < 0.05, 0.07, respectively). We concluded that intraluminal hydrogen ion concentration creates an afferent warning stimulus that produces prompt airway-protective responses.