[1999]LABORATORY EVALUATION OF FOUR PORTABLE VENTILATORS (PVTs).
Robert Campbell RRT, Paul Austin CRNA, James Lawson RRT, Jay Johannigman MD, Kenneth Davis Jr. MD, Richard Branson RRT. University of Cincinnati, Cincinnati, OH.
INTRODUCTION: Traditionally, PVTs have high imposed work of breathing (WOBI). Newer PVTs include flow triggering and PSV to minimize WOBI. We compared the WOBI and response time (RT) of 4 PVTs on a lung model.
Methods: A two-chambered test lung (TTL) was modified to mimic spont breathing. An Evita 4 (Drager) powered the ?drive? lung at 3 volume and flow conditions: 1) 300 ml @ 40 L/min, 2) 500 ml @ 60 L/min, and 3) 800 ml @ 80 L/min. TTL characteristics were C of 50 ml/cmH2O and R of 5 cmH2O/L/sec. PVTs (Achieva, T-Bird, 740, LTV) were attached to ?pt? lung with flow trigger of 2 and set at PEEP/PSV combinations of: 0/0, 0/10, 5/0, and 5/10. Five breaths at each setting were analyzed and data recorded = WOBI, peak negative pressure (PNP), RT and VT.
Results: WOBI was higher with Achieva with PEEP set. Table 1 shows results (mean ± SD) at 0/10 (cond #2). Table 2 shows results at 5/0 (cond #2).
Table 1.
WOBI (mJ/L)
PNP (cmH2O)
RT (Sec)
Achieva
0.2 ± 0.02
-0.5 ± 0.03
0.12 ± 0.02
LTV 1000
0.9 ± 0.2
-0.9 ± 0.1
0.14 ± 0.02
T-Bird
0.06 ± 0.02
-0.1 ± 0.03
0.14 ± 0.02
740
1.0 ± 0.3
-1.24 ± 0.06
0.17 ± 0.02
Table 2.
WOBI (mJ/L)
PNP (cmH2O)
RT (Sec)
Achieva
67.0 ± 3.0
0.41 ± 0.2
0.5 ± 0.04
LTV 1000
18.0 ± 1.5
-0.1 ± 0.1
0.25 ± 0.02
T-Bird
13.0 ± 0.2
2.30 ± 0.03
0.27 ± 0.02
740
8.0 ± 1.3
3.6 ± 0.1
0.32 ± 0.02
CONCLUSION: WOBI on these PVTs is clinically acceptable and may be minimized by adding PSV.
