2006 OPEN FORUM Abstracts
Variation of Fractional Delivered Oxygen Concentration (FDO2) during Spontaneous Breathing from a Manual Resuscitator: A Bench Study
Anthony J. Asciutto RRT, Robert S.
Slonac RRT, Michael K. Howard MBA RRT, John D. Davies RRT FAARC, Michael A.
Gentile RRT FAARC, Robert B. Campbell MBA RRT, Neil MacIntyre
MD FAARC Duke University Medical Center, Durham, NC.
Background: Manual resuscitators are primarily used in clinical situations such as
emergency resuscitation, moderate sedation, endotracheal intubation, and
patient transport to provide ventilation and support oxygenation. At times, our
clinical practice may allow a spontaneously breathing patient to breathe
unassisted from a manual resuscitator. We hypothesize that a patient would
receive a FDO2 of 1.0 when breathing spontaneously from a manual
resuscitator.
Methods: A bench study
was conducted to test the hypothesis. A double-chambered test lung (Vent Aid
TTL, Michigan Instruments, Inc. Grand Rapids, MI) with a crossover latch was
used in concert with a Puritan Bennett 840 ventilator (Nellcor Puritan BennettT
Inc., Carlsbad, CA). The ventilator was connected to the right chamber in order
to drive the left chamber into a spontaneous inspiration. An oxygen monitor
(Maxtec Oxygen Monitor, Maxtec, Inc. Salt Lake City, UT) connected to the left
chamber was used to analyze the FDO2 from the manual resuscitator used
by our institution (AirFlow Small
Adult Resuscitator, AF 5100 Series, Ventlab Corp., Mocksville, NC). Ventilator
tidal volumes of 400, 480, and 560 mL and inspiratory flow rates of 40, 60, 80
and 100 L/m were used to simulate different
spontaneous breathing patterns. Data were collected for each tidal volume and
inspiratory flow combination at three oxygen flow rates (5, 10, 15 L/m)
provided to the resuscitator.
Results: The FDO2 data points are presented in the table below.
| 40 L/m | 60 L/m | 80 L/m | 100 L/m | 40 L/m | 60 L/m | 80 L/m | 100 L/m | 40 L/m | 60 L/m | 80 L/m | 100 L/m | |
| 5 L | 5 L | 5 L | 5 L | 10 L | 10 L | 10 L | 10 L | 15 L | 15 L | 15 L | 15 L | |
| VT 400 | 76.5 | 82.5 | 88.2 | 91 | 74 | 73.3 | 77.8 | 80.5 | 87.5 | 84.2 | 83.2 | 87.6 |
| VT 480 | 74 | 79.5 | 84 | 88 | 71.3 | 70.6 | 75.1 | 78.5 | 87.9 | 81.1 | 81.2 | 84 |
| VT 560 | 70 | 77 | 82.4 | 85.6 | 71.1 | 69.4 | 74 | 77.1 | 85.4 | 78 | 79.1 | 82.4 |
Conclusion: In this bench study, the FDO2 measurements from a manual
resuscitator during simulated spontaneous breathing, without manual assistance,
demonstrated an unexpected degree of variability with a range from 69.4 to 91%.
A FDO2 of 1.0 was not delivered under the testing conditions.