Intraesophageal pH monitoring during acid infusion in patients with systemic sclerosis.

Incidental clinical observations suggest that buffering substances may accumulate in the distal esophagus of patients with systemic sclerosis. The aim of our study was to assess if the buffering capacity of the intraesophageal milieu is increased in patients with systemic sclerosis and if this effect can be correlated to some pathophysiological aspects of the disease. We recorded intraesophageal pH before and during a 10-min intraesophageal infusion of acid (HCl 0.01 N, 1 ml/min), as well as esophageal motility and clearance function, in 16 patients with systemic sclerosis and 10 healthy subjects. Esophageal buffering capacity expressed as the area under the curve of intraesophageal pH during acid infusion was significantly higher in the patients than in the controls, and this variable was directly correlated with esophageal clearing time. In conclusion, esophageal buffering capacity is increased in patients with systemic sclerosis and is possibly the consequence of the accumulation of buffering substances in the distal esophagus.