Pharyngeal reflux (LPR) is defined as a chronic symptom or mucosal damage caused by abnormal regurgitation of gastric contents into the upper respiratory tract. Gastric contents include bile acids as well as pancreatic enzymes in addition to pepsin and gastric acid, all of which can cause damage to tissues that cannot tolerate these substances. Gastrophageal reflux can cause many respiratory-related symptoms: hoarseness, throat clearing, excessive laryngeal and postnasal discharge, foreign body sensation in the throat, choking sensation, dysphagia, rhinitis, pharyngitis, otitis media, cough, asthma, interstitial pneumonia, etc. If combined with gastroesophageal reflux, there are: heartburn, chest pain, acid reflux, indigestion, etc. However, most people with pharyngeal reflux clinically do not have symptoms of heartburn, nausea, vomiting, etc. in the digestive tract. Therefore, it is difficult to diagnose clinically. The etiology of pharyngeal reflux is: gastric emptying dysfunction, regurgitation of H ions and pepsinogen in the stomach into the airway, and when acidic H ions cause the pH of the mucosal surface to drop below 6, pepsinogen is activated to turn into pepsin, which dissolves the proteins on the cell membrane and damages the mucosal tissue. Inhalation therapy for children with chronic cough and asthma has been used in our asthma specialist clinic to obtain mostly good results. If the inhalation effect is not satisfactory the specialist will do a few tests to exclude infectious factors such as mycoplasma infection, bacterial infection, etc., or check the upper airway for the presence of chronic adenoid hypertrophy, rhinitis sinusitis that is not controlled, etc. However, there is no good test for gastroesophageal reflux cough, the fourth component of chronic cough in children. The current traditional practice in China is to perform an esophageal pH test, which can determine reflux below pH 4, and its normal pH scale is set at 4, because only if the pH is below 4 does the patient have heartburn symptoms. The diagnostic criteria for gastroesophageal reflux (GERD) are heartburn and reflux esophagitis. When LPR is not combined with GERD, the patient’s reflux pH is 5 to 6 and the patient has no GI symptoms but can cause damage to the airway mucosa. Non-acid reflux monitored in the esophagus above pH 4 is not significant for the esophageal mucosa itself because the normal esophageal pH is above 4. In addition, pharyngeal reflux extrapolated from esophageal non-acid reflux is highly inaccurate, as such extrapolation does not reflect real-time changes in pharyngeal pH. It has been reported that 80% of pharyngeal reflux cases are negative using esophageal pH testing. In addition, gastroesophageal reflux testing requires the insertion of a thick tube into the lower esophagus, which is a painful procedure that many children are reluctant to accept, making the test unpopular. Therefore, at present, although our specialists consider whether there is pharyngeal reflux in people with chronic cough or unsatisfactory asthma control, there is no effective test method, so we can only use experimental treatment to make judgment. It uses a silicone tube with a diameter of about 1 mm, which is inserted into the nasopharynx of the child and is connected wirelessly to the receiver via Bluetooth, and can be worn for 24 hours to accurately detect changes in pharyngeal PH during the day, night and meal times, thus accurately determining whether chronic cough or poor asthma is caused by gastric acid or acidic gas Reflux. If your child has a recurrent cough or asthma despite standardized pediatric respiratory care, it is recommended that an airway PH test be performed, and an appointment for this test can be made at the pediatric respiratory clinic of Dr. Wu, Yang or Zhang.