Design and validation of an indicator gas injector for multiple gas washout tests in mechanically ventilated patients.
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.
Huygen
P E
PE
Department of Surgery, University Hospital Dijkzigt, Rotterdam, The Netherlands.
Feenstra
B W
BW
Holland
W P
WP
Ince
C
C
Stam
H
H
Bruining
H A
HA
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