Gastric-oesphageal (GOR) reflux during spirometry : prevalence and effects (Poster)

Introduction: Variability during spirometry can persist despite control of technical and personal factors. We hypothesised that spirometry may induce GOR which may influence upper airway variability leading to variability of spirometry. Aim: Pilot study assessing prevalence of GOR during spirometry and its effects on spirometry variability in subjects having outpatient GOR assessment. Method: At the end of oesophageal manometry and 24hr pH monitoring, 56 subjects performed 2 sets of spirometry separated by 10-minutes. The De-Meester score quantified 24hr GOR (≥14.72 in significant GOR). Assessment for GOR during spirometry started with 1st spirometry and ends with 2nd spirometry manouvres. Variability of spirometry was assessed between those with GOR and no GOR. Results: In 26 subjects (44%) had GOR during spirometry assessment: 18 during the 10-minute break with 3 persisting into the 2nd spirometry, 5 throughout assessment, and 3 during spirometry only. They tended to have higher De-Meester scores (mean 39.8 vs 26.8, t-test p=0.13) and were more likely have a GOR event preceding the 1st spirometry (median time interval [min] 8.5 [IQR 5–12] vs 25 [IQR 10–70]), compared to 30 subjects without GOR during spirometry assessment. In the GOR group both FEV1 and PEF were reduced in the second spirometry set; FEV1 by 84mL (p<0.05), PEFR by 0.5L/s (p<0.001). FVC was is not changed. Mean variability of spirometry (%) ± SD was similar between GOR and non-GOR groups. Conclusion: GOR occurs during and following spirometry in subjects having outpatient GOR assessment, but does not significantly impact spirometry variability over 10-minutes in this patient population.