2006 OPEN FORUM Abstracts
Comparison of Static Compliance on Six Ventilators
Davies, RRT, Mechelle Wilson, RRT,
Keith Matlock, CRT, Jana Maciejczak, CRT, Doug Pursley M.Ed. RRT
Ozarks Technical Community College, Springfield, MO
Introduction: The purpose of this study was to test the accuracy of static compliance (Cstat) measurements compared to a control value from a Michigan Test Lung. The ventilators tested for Cstat accuracy were the Maquet Servo i, Drager Evita XL, Drager E4, Viasys Avea, Puritan Bennett 840, and the Puritan Bennett 7200.
Methods: We compared Cstat by connecting the different types of ventilators with the same ventilator circuit and no humidifier to the Michigan Test Lung Model 560li. The Michigan Test Lung was set to compliance values of 10, 50, 80, and 100 cmH2O. Volume controlled ventilation with a set tidal volume of 600ml, f 12 breaths per minute, and flow rate of 45 l/m was set on each ventilator.
Results: With zero PEEP, the ventilators ranked in the following order from most accurate to least accurate (overall average percent differences from the control value are in parenthesis): PB 7200 (1.25%), Maquet Servo i (4.2%), Viasys Avea (4.6%), PB 840 (10%), Drager E4 (22.5%), and Drager XL (26.7%). When five cmH2O PEEP was applied to the circuit, the ranking from most accurate to least accurate was: Viasys Avea (5%), Maquet Servo i (7.1%), PB 7200 (11.25%), PB 840 (16.25%), Drager E4 (25.4%), and Drager XL (29.6%).
|PB 7200||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP||PB 840||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP|
|Avea||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP||Drager XL||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP|
|Servoi||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP||Drager E4||Set Cstat||Meas. Cstat||% Diff. between set and meas.||Plat||Set PEEP|
Conclusion: In this bench test we found that when compared to the
set compliance from the Michigan Test Lung, all six of the ventilators gave
more accurate measurements with zero set PEEP and were less accurate when 5
cmH2O PEEP was added to the ventilator circuit. Plateau pressures were
remarkably consistent across most of the spectrum of compliance between the six
ventilators. The Viasys Avea gave the narrowest range of error between zero
PEEP and five cmH2O PEEP.