Nasal pH in patients with chronic rhinosinusitis before and after endoscopic sinus surgery

Purpose Physiologically acidic nasal pH depends on intact nasal mucosal function. The aim of this study was to determine nasal pH in patients with chronic rhinosinusitis and to investigate the changes in pH related to mucosal healing after endoscopic sinus surgery. Materials and methods Normal subjects and the patients with chronic rhinosinusitis who showed no recurrence after endoscopic sinus surgery were enrolled. Using a portable pH meter and a glass-tipped probe, nasal pH was measured in the inferior meatus in normal subjects and patients before and after surgery at 3 months. Results The mean (± SD) nasal pH was 6.5 ± 0.5 (5.9 to 7.3) in 19 normal subjects, and 6.7 ± 0.6 (5.3 to 7.6) in 19 CRS patients before surgery, which showed no significant difference between the groups. The nasal pH values were in the range of 3.8-7.7 (mean ± SD 5.7 ± 0.9) at 3 months after surgery, and significantly lower than the preoperative values in patients (P =.004). The patients showing pH lower than 6.0 accounted for 10.5% before surgery, but 68.4% after surgery. Conclusions Normal nasal pH was in the slightly acidic range, and the mean nasal pH of patients with chronic rhinosinusitis fell within normal limits as well, which indicates that chronic rhinosinusitis may not disturb the electrolyte milieu of the nasal mucosa. The average nasal pH measured at 3 months after endoscopic sinus surgery exhibited acidity of pH 5.7. The factors causing a fall in nasal pH during the healing period after the sinus surgery remain to be elucidated.