2006 OPEN FORUM Abstracts
THE EFFECT OF RESISTANCE ON TIDAL VOLUME DELIVERED FROM THE PNEUPAC ventiPAC MODEL V200D MRI-COMPATIBLE PORTABLE VENTILATOR
Lance Lothert, RRT, CPFT, Immanuel St. Joseph's Hospital Mayo Health System,
Mankato MN, USA.
Background: Portable ventilators are used in multiple settings such as transport, emergency
departments and MRI. Most portable ventilators do not measure tidal volume (VT).
This study was performed to assess the effects of increased resistance on tidal
volume delivered from a pneumatic, time-cycled portable ventilator.
Method: The
ventiPAC ventilator was connected to a mechanical lung (Michigan Instruments,
Grand Rapids, MI) with a compliance of .10 L/cm H2O. An inspiratory
flow of 30 L/min and an FIO2 of .45 were held constant during each
measurement.
The delivered VT was measured by a pneumotachometer (direct connect, Medical Graphics, St.Paul,
MN). Two fixed resistors were placed in-line and multiple measurements were
made at multiple inspiratory and expiratory times.
Results:
| TI | TE | 5 cmH2O/L/sec | 20 cmH2O/L/sec |
| .5 | 1.5 | -0.6% | -1.8% |
| .5 | 2 | -1.2% | -1.2% |
| .5 | 4 | -1.2% | -1.2% |
| .75 | 1 | .09% | -1.7% |
| .75 | 1.5 | -1.7% | -4.4% |
| .75 | 2 | -3.9% | -6.3% |
| .75 | 4 | -10.1% | -12.6% |
| 1 | 1 | -0.3% | -2.9% |
| 1 | 1.5 | -2.6% | -5.3% |
| 1 | 2 | -2.8% | -5.3% |
| 1 | 4 | -8.8% | -11.1% |
| 1.5 | 1.5 | 0.3% | -2.6% |
| 1.5 | 2 | -1.1% | -3.6% |
| 1.5 | 4 | -4.1% | -6.9% |
| 2 | 2 | 2.2% | -0.6% |
| 2 | 4 | -0.4% | -3.9% |
Conclusion:
1. T was affected less than 13% at an increased resistance of 20
cmH2O/L/sec.
2. T would not be significantly affected in the event of a physiologic increase in inspiratory
resistance, which would make a pneumatic, time-cycled portable ventilator, safe
for clinical work.