TY - JOUR T1 - Long-Term Stability of a Portable Carbon Monoxide Single-Breath Diffusing Capacity Instrument JF - Respiratory Care DO - 10.4187/respcare.04983 SP - respcare.04983 AU - Laura Gochicoa-Rangel AU - Rogelio Pérez-Padilla AU - Juan Carlos Vázquez-García AU - Mónica Silva-Cerón AU - Silvia Cid-Juárez AU - David Martínez-Briseño AU - Paul L Enright AU - Robert Jensen AU - Luis Torre-Bouscoulet Y1 - 2016/09/27 UR - http://rc.rcjournal.com/content/early/2016/09/27/respcare.04983.abstract N2 - BACKGROUND: The 2005 American Thoracic Society/European Respiratory Society guidelines for single-breath diffusing capacity of the lung for carbon monoxide (DLCO) recommend a weekly biological control test and/or DLCO simulator to detect instrument error drift. Very little has been published regarding the results of such a quality assurance program. Our aim was to analyze the long-term stability of a portable DLCO instrument.METHODS: We used a new EasyOne Pro system and checked its accuracy using a DLCO simulator with 2 reference gases (concentration A: carbon monoxide [CO] = 0.1% and helium = 6.52%; concentration B: CO = 0.08% and helium = 7.21%) during the first 3 y of use in our large clinical laboratory. To detect instrument drift, a healthy woman (MSC), age 43 y old at baseline, tested herself every week during this period of time.RESULTS: More than 6,000 spirometry and 5,000 DLCO maneuvers were done using this instrument for patients during these 3 y. There were no failures in the daily volume and flow checks or the CO and helium calibration checks performed automatically by the instrument. The differences between the simulator DLCO and the measured DLCO were −0.91 ± 1.33 mL/min/mm Hg and −0.61 ± 1.45 mL/min/mm Hg for concentration A and concentration B, respectively. The results of the 110 biological control tests were: mean 30.8 ± 1.7 mL/min/mm Hg (95% CI 30.5–31.1), coefficient of variation of 5.4% in DLCO, and repeatability of 2.5 mL/min/mm Hg. Only 4 measurements were outside ±3 mL/min/mm Hg (3.6%). Her mean alveolar volume was 4.2 ± 0.25 L with coefficient of variation of 6.2%; her inspired volume was 3.05 ± 0.14 L, and coefficient of variation = 4.5%.CONCLUSIONS: Measurements of DLCO were stable over the 3-y period without any need for manual recalibration of the instrument. The biological control was as good as the DLCO simulator to evaluate this kind of device in a long-term laboratory quality control program. ER -