A causal link between gastroesophageal reflux disease (GORD) and respiratory symptoms is unclear. The 2019 CHEST guideline recommends GORD treatment only in the context of clinical symptoms, signs or a positive test.

We evaluated the feasibility of 24-hour ambulatory impedance testing as a minimally invasive test to identify GORD contributing to symptoms. Our centre performs flexible bronchoscopy and pH-Multichannel intraluminal impedance (pH-Mii?) probe placement under general anaesthesia as part of the assessment of complex persistent respiratory symptoms. Oesophageal probe placement is confirmed by direct laryngoscopy before x-ray confirmation of probe sensor position. The probe is removed 18-24 hours later, and study analysed using ESPGHAN EURO-PIG standards. 43 children had this combined procedure from Sept 2021 to Feb 2023, 18 (42%) for CF/PCD exacerbations, 11 (26%) for recurrent chest infection, 9 (21%) for recurrent croup and 5 (12%) for persistent x-ray changes.

Age distribution was: <1y = 2, 1-5y = 11, 6-12y = 24, >12y = 6 (mean 6.55 + 4.55y)). Testing succeeded in 37/43 (86%). 4 (9%) did not tolerate the probe (ages 1-5 years) and 2 (5%) studies failed for technical reasons. 6/37 were studied while taking proton pump inhibitor (PPI). 12/31 children studied off PPI had pathological reflux (despite no GORD-specific symptoms -?silent GORD?) prompting initiation of PPI therapy.

Once in situ, pH-Mii is well tolerated, portable and does not require admission. Ambulatory pH-Mii in children undergoing elective flexible bronchoscopy is a key investigation to exclude GORD contributory to persistent respiratory symptoms as it may identify GORD with extraoesophageal manifestations amenable to targeted treatment.