title: Design and validation of an indicator gas injector for multiple gas washout tests in mechanically ventilated patients.
abstract: A device to produce a stepwise indicator gas fraction variation to initiate a washout test in mechanically ventilated patients is described. The device, which can be used in conjunction with the commonly used Siemens-Elema series 900 ventilators, is based on simple, off-the-shelf technology. It features the simultaneous use of two indicator gases (so that the influence of diffusion processes in the gas exchange to the patient can be measured) and maintains a nearly constant FIO2 during a washout procedure. With this indicator gas injector, the transition time of the indicator gas fraction at the beginning of a washout proved to be short enough to detect ventilation inhomogeneity by visual inspection of the washout curves. Functional residual capacity measurements using this device are presented on a test lung with known volume, on healthy volunteers, and on critically ill patients.
authors.affiliation: Department of Surgery, University Hospital Dijkzigt, Rotterdam, The Netherlands.
authors.forename: P E
authors.initials: PE
authors.lastname: Huygen
authors.forename: B W
authors.initials: BW
authors.lastname: Feenstra
authors.forename: W P
authors.initials: WP
authors.lastname: Holland
authors.forename: C
authors.initials: C
authors.lastname: Ince
authors.forename: H
authors.initials: H
authors.lastname: Stam
authors.forename: H A
authors.initials: HA
authors.lastname: Bruining
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D012119:Respiration; D012122:Ventilators, Mechanical