Figure 1.

 Tracings of concurrent oesophageal manometry, pH, and impedance. Example of a “reflux cough” sequence. The impedance tracing shows a retrogradely propagated drop consistent with liquid reflux, and the oesophageal pH fell more than 1 pH unit but remained above 4 (weakly acidic reflux). The manometric tracing shows a cough burst consisting of phasic, short duration, rapid pressure rises occurring simultaneously and with the same pressure configuration at all manometric recording sites. Cough occurred 82 seconds after the start of a weakly acidic reflux event.