Figure 2From: Proton pump inhibitor-responsive chronic cough without acid reflux: a case report Results of 24-h esophageal pH monitoring prior to re-initiation of PPI in case 1. Acid reflux in the esophagus was considered present if pH was 4 or lower. Some cough and acid reflux were observed, little cough-related acid reflux was noted (*; cough, #; acid reflux, $; cough-related acid reflux).Back to article page