BACKGROUND: Measurement of functional residual capacity (FRC) is of considerable interest for monitoring patients with lung injury. The lack of instruments has impeded routine bedside FRC measurement. Recently, a simple automated method for FRC assessment by O2 washout has been introduced. We designed this study to evaluate the accuracy of FRC measurement using the O2 washout technique. METHODS: The LUFU system (Draeger, Luebeck, Germany) estimates FRC by O2 washout, a variant of multiple breath nitrogen washout. This technique uses a sidestream O2-analyzer to calculate FRC from end-inspired and end-expired O2 concentrations during fast changes of Fio2. We measured FRC in 23 healthy, spontaneously breathing volunteers in the sitting position using three techniques: 1) helium dilution (FRC-He), 2) body plethysmography (FRC-bp), 3) oxygen washout (FRC-O2). RESULTS: FRC-O2 (mean 4.1 +/- 1.1 L, range 2.4-6.9 L) corresponds with FRC-He (mean 4.0 +/- 1.0 L, range 2.4-6.2 L; bias of FRC-O2: -0.2 +/- 0.4 L) and FRC-bp (mean 4.2 +/- 1.0 L, range 2.8-6.1 L; bias of FRC-O2: 0.1 +/- 0.6 L). CONCLUSIONS: The bias and precision of the O2 washout technique using the LUFU system were clinically acceptable when compared with FRC-He and FRC-bp for FRC assessment in spontaneously breathing volunteers.
BACKGROUND: Measurement of functional residual capacity (FRC) is of considerable interest for monitoring patients with lung injury. The lack of instruments has impeded routine bedside FRC measurement. Recently, a simple automated method for FRC assessment by O2 washout has been introduced. We designed this study to evaluate the accuracy of FRC measurement using the O2 washout technique. METHODS: The LUFU system (Draeger, Luebeck, Germany) estimates FRC by O2 washout, a variant of multiple breath nitrogen washout. This technique uses a sidestream O2-analyzer to calculate FRC from end-inspired and end-expired O2 concentrations during fast changes of Fio2. We measured FRC in 23 healthy, spontaneously breathing volunteers in the sitting position using three techniques: 1) helium dilution (FRC-He), 2) body plethysmography (FRC-bp), 3) oxygen washout (FRC-O2). RESULTS: FRC-O2 (mean 4.1 +/- 1.1 L, range 2.4-6.9 L) corresponds with FRC-He (mean 4.0 +/- 1.0 L, range 2.4-6.2 L; bias of FRC-O2: -0.2 +/- 0.4 L) and FRC-bp (mean 4.2 +/- 1.0 L, range 2.8-6.1 L; bias of FRC-O2: 0.1 +/- 0.6 L). CONCLUSIONS: The bias and precision of the O2 washout technique using the LUFU system were clinically acceptable when compared with FRC-He and FRC-bp for FRC assessment in spontaneously breathing volunteers.
Authors: N Patroniti; M Saini; A Zanella; D Weismann; S Isgrò; G Bellani; G Foti; A Pesenti Journal: Intensive Care Med Date: 2008-07-23 Impact factor: 17.440
Authors: Frederique Paulus; Denise P Veelo; Selma B de Nijs; Ludo F M Beenen; Paul Bresser; Bas A J M de Mol; Jan M Binnekade; Marcus J Schultz Journal: Crit Care Date: 2011-08-05 Impact factor: 9.097