Objective: To assess whether severe gastroesophageal reflux (GER) is associated with abnormalities in lung function including measures of lung volume and gas diffusion.
Methods: Data from 147 patients with obesity (body mass index [BMI] range, 31.7 to 70 kg/m2) who presented for obesity surgery was analyzed retrospectively. A questionnaire was completed preoperatively that included a history of GER, frequency and severity of symptoms, investigations, and medications used. A history of lung disease, sleep-disordered breathing, and smoking also was obtained. A physician who was blinded to lung function graded GER severity prospectively by the results of pH monitoring and/or gastroscopy, and medication use. Spirometry, lung volumes, and gas transfer were measured preoperatively.
Results: Patients with severe GER had reduced levels of the diffusing capacity of the lung for carbon monoxide (Dlco) [21.1 mL/min/mm Hg; 95% confidence interval (CI), 18.9 to 23.2], as measured by CO transfer, compared with those patients without GER (26.3 mL/min/mm Hg; 95% CI, 24.4 to 28.2; p = 0.001). This remained significant after adjusting for age, gender, BMI, and smoking history. Gas transfer corrected for lung volume also was reduced in the group with severe GER (4.6 mL/min/mm Hg per L; 95% CI, 4.3 to 4.9) compared to the group without GER (5.3 mL/min/mm Hg per L; 95% CI, 5.1 to 5.5; p = 0.001). There was no significant difference in other measures of lung function.
Conclusions: Severe GER is associated with an impairment of gas exchange. This may be due to microaspiration of gastric acid or fluid into the airways.