TY - JOUR T1 - Reference Values for the Diffusing Capacity Determined by the Single-Breath Technique at Different Altitudes: The Latin American Single-Breath Diffusing Capacity Reference Project JF - Respiratory Care SP - 1217 LP - 1223 DO - 10.4187/respcare.04590 VL - 61 IS - 9 AU - Juan Carlos Vázquez-García AU - Rogelio Pérez-Padilla AU - Alejandro Casas AU - Patricia Schönffeldt-Guerrero AU - Jonatan Pereira AU - Claudia Vargas-Domínguez AU - Mónica Velázquez-Uncal AU - David Martínez-Briseño AU - Luis Torre-Bouscoulet AU - Laura Gochicoa-Rangel Y1 - 2016/09/01 UR - http://rc.rcjournal.com/content/61/9/1217.abstract N2 - BACKGROUND: The lung diffusion capacity (DLCO) determined by the single-breath technique greatly helps in the differential diagnosis and classification of severity of common lung diseases. However, widespread use of single-breath DLCO tests in Latin America has been limited, in part, by the lack of appropriate reference values. Our objective was to derive robust reference equations for single-breath DLCO from healthy Hispanic adults, using the most recent guidelines and taking into account altitude above sea level and hemoglobin.METHODS: We recruited healthy adults from Caracas (690 m), Santiago (650 m), Mexico City (2,240 m), and Bogota (2,640 m). DLCO testing was completed using an instrument that exceeds American Thoracic Society/European Respiratory Society 2005 guidelines for spirometry and single-breath DLCO and provided centralized training and a quality assurance program.RESULTS: We included 480 healthy Hispanic adults (58.3% women) with a mean age of 46 y (range 22–83 y). Their mean ± SD single-breath DLCO was 30.4 ± 9.2 mL/min/mm Hg. Results as a percentage of predicted by Crapo's reference values (the closest to obtained values) were 83 ± 10% (Caracas), 91 ± 10% (Santiago), 104 ± 17% (Mexico City), and 118 ± 19% (Bogota), and current suggested adjustments by hemoglobin or altitude did not correct differences, especially in Santiago and Caracas.CONCLUSIONS: We recommend these new single-breath DLCO reference equations to predict single-breath DLCO in Latin America performed with current instruments and procedures and including as a predictor altitude above sea level. ER -