Abstract
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.
1
Introduction
Nasal pH represents nasal mucosal pH, more precisely, the pH of nasal surface secretions in vivo. Physiologic range of the human nasal pH has been reported to be slightly acidic (6.3–6.9 on average) relative to plasma pH of 7.4 . It has been documented that nasal pH does not vary with daily activities, and there are no diurnal changes .
Acidic airway surface liquid may confer an advantage in the innate host defense by inhibiting bacterial adhesion and promoting lysozyme activity. It has been demonstrated that the apical membrane of the airway epithelium possesses the mechanisms capable of acidifying the surface liquid: the passive distribution of protons in response to transepithelial electric potential difference , the apical proton channels secreting H + into airway surface liquid , and the apical Na + /H + exchanger .
Nasal pH representing the state of electrolytes in nasal mucosa can be altered by disease or airway inflammation because the pH maintenance depends on intact nasal epithelium. Therefore, monitoring of nasal pH could provide an objective parameter or indicator for the nasal mucosal status in various clinical practices such as intranasal drug administration . Using a portable pH meter and a glass-electrode probe is a simple, fast, and noninvasive method even a non-otolaryngologist can perform on an outpatient basis.
Chronic rhinosinusitis (CRS), one of the most common and significant problems in otolaryngology clinics, concurrently affects the mucosa of the nose and paranasal sinuses. However, there have been little data on nasal pH alterations in inflammatory/infectious diseases of the nose.
The aim of the present study was to determine nasal pH in CRS patients and to investigate the changes in pH related to mucosal healing after endoscopic sinus surgery (ESS).
2
Materials and methods
2.1
Subjects
Data were collected on normal subjects and CRS patients undergoing ESS between October 2009 and June 2010. This study was approved by the institutional review boards of our hospital (PC09FZZZ0057). Normal subjects without nasal or systemic diseases were recruited. All patients undergoing ESS fulfilled diagnostic criteria for adult CRS by the American Academy of Otolaryngology-Head and Neck Surgery, and had failed medical management . Smokers and the patients with nasal allergy, other rhinitis, or current use of topical nasal medications were excluded from the study. Only the data of the patients who had bilateral/the right CRS with nasal polyps and showed no symptoms and signs of recurrence at postoperative 3 months were included in the analysis.
2.2
Intranasal pH Measurement
Nasal pH was measured in normal subjects and CRS patients before surgery using a portable pH meter (Digitrapper Mk III, Synectics Medical) and a 2.13-mm-diameter flexible glass-tipped probe (Comfortec PLUS PHNS, Sandhill Scientific) approved for esophageal pH monitoring. The pH meter was calibrated with pH 4.0 and pH 7.0 buffer standards before each measurement. In CRS patients, the involved nasal cavities were cleaned by suctioning nasal discharges. The probe was inserted along the inferior meatus, placed at a depth of 4 cm from the nostril, and fixed outside to the nose and forehead with paper tape. To prevent artificial pH changes, probe lubricant, local anesthetic, or vasoconstrictor was not used.
The pH meter was read when the pH level had become stable. The probe stayed in the nose for approximately 15 s before pH settled into a value. After washing the probe in distilled water, the same procedure was repeated three times at 5-min intervals to average the three consecutive readings. All study subjects adapted quickly to the probe and well tolerated the procedure. CRS patients underwent ESS from a single rhinologist, and the pH measurements were carried out by the same method at the 3-month follow-up.
2.3
Data analysis
Statistical analysis was performed to compare the preoperative pH of the CRS group with that of the normal group using t -test. The difference between the pre- and postoperative pH values was compared in the CRS group using the paired t -test. A P value of < .05 was considered significant.
2
Materials and methods
2.1
Subjects
Data were collected on normal subjects and CRS patients undergoing ESS between October 2009 and June 2010. This study was approved by the institutional review boards of our hospital (PC09FZZZ0057). Normal subjects without nasal or systemic diseases were recruited. All patients undergoing ESS fulfilled diagnostic criteria for adult CRS by the American Academy of Otolaryngology-Head and Neck Surgery, and had failed medical management . Smokers and the patients with nasal allergy, other rhinitis, or current use of topical nasal medications were excluded from the study. Only the data of the patients who had bilateral/the right CRS with nasal polyps and showed no symptoms and signs of recurrence at postoperative 3 months were included in the analysis.
2.2
Intranasal pH Measurement
Nasal pH was measured in normal subjects and CRS patients before surgery using a portable pH meter (Digitrapper Mk III, Synectics Medical) and a 2.13-mm-diameter flexible glass-tipped probe (Comfortec PLUS PHNS, Sandhill Scientific) approved for esophageal pH monitoring. The pH meter was calibrated with pH 4.0 and pH 7.0 buffer standards before each measurement. In CRS patients, the involved nasal cavities were cleaned by suctioning nasal discharges. The probe was inserted along the inferior meatus, placed at a depth of 4 cm from the nostril, and fixed outside to the nose and forehead with paper tape. To prevent artificial pH changes, probe lubricant, local anesthetic, or vasoconstrictor was not used.
The pH meter was read when the pH level had become stable. The probe stayed in the nose for approximately 15 s before pH settled into a value. After washing the probe in distilled water, the same procedure was repeated three times at 5-min intervals to average the three consecutive readings. All study subjects adapted quickly to the probe and well tolerated the procedure. CRS patients underwent ESS from a single rhinologist, and the pH measurements were carried out by the same method at the 3-month follow-up.
2.3
Data analysis
Statistical analysis was performed to compare the preoperative pH of the CRS group with that of the normal group using t -test. The difference between the pre- and postoperative pH values was compared in the CRS group using the paired t -test. A P value of < .05 was considered significant.
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