PT  - JOURNAL ARTICLE
AU  - Gochicoa-Rangel, Laura
AU  - Pérez-Padilla, Rogelio
AU  - Vázquez-García, Juan Carlos
AU  - Silva-Cerón, Mónica
AU  - Cid-Juárez, Silvia
AU  - Martínez-Briseño, David
AU  - Enright, Paul L
AU  - Jensen, Robert
AU  - Torre-Bouscoulet, Luis
TI  - Long-Term Stability of a Portable Carbon Monoxide Single-Breath Diffusing Capacity Instrument
AID  - 10.4187/respcare.04983
DP  - 2017 Feb 01
TA  - Respiratory Care
PG  - 231--235
VI  - 62
IP  - 2
4099  - http://rc.rcjournal.com/content/62/2/231.short
4100  - http://rc.rcjournal.com/content/62/2/231.full
AB  - 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.