The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

OXYGEN DELIVERY THROUGH PORTABLE VENTILATORS: A COMPARISON OF FOUR METHODS

Jenni L. Raake, BS, RRT Children's Hospital Medical Center Cincinnati, Ohio

Background: Patients receiving home mechanical ventilation often use supplemental oxygen. There are several methods used for delivering oxygen to a portable ventilator. I set out to determine the most efficient method for delivery oxygen to patients. Method: An LP-10 (Aequitron, Inc. Minneapolis, MN) was connected to a test lung. An oxygen analyzer (Hudson, Inc. Temecula, CA) was placed in the ventilator circuit (Allegiance, Round Lake, Il) at the circuit wye. The ventilator was set at tidal volumes of 100, 200, 300, 400, and 500 cc. The rate was set at 6, 10, 15, and 20 breaths per minute with an inspiratory time of 1 second. Oxygen was delivered using four different Methods: 1) a line adapter (Hudson) was attached to the air entrainment port of the ventilator, 2) a line adapter (Hudson) was attached to the ventilator outlet port, 3) an IMV bag was connected to the ventilator outlet port, and 4) a side-port connector (Bivona, Inc. Gary, IN) was placed at the circuit wye. The analyzer was used to measure the FiO_{2} when 1 lpm of oxygen was delivered using each oxygen delivery method at each variation in ventilator settings. The bench test was run four times using two different ventilators. Results: In all four delivery methods, the FiO_{2} was higher at lower ventilator settings. As tidal volumes and rates were increased, the FiO_{2} decreased. There were differences in FiO_{2} levels based on the delivery method used. When oxygen was introduced using either the IMV bag or the adapter at the outlet port, concentrations were consistently higher throughout all ventilator settings. When oxygen was introduced through the air entrainment port or at the circuit wye, the lowest oxygen concentrations were detected. Experience: In portable ventilation, the FiO_{2} values are expected to decrease as minute ventilation increases. This is because the room air that is generated by the ventilator will increase with increases in minute ventilation. The FiO_{2} relies on the both the minute ventilation produced by the portable ventilator and the flow rate of oxygen. To provide the most efficient delivery of oxygen to patients, those methods which require the lowest flow rates of gas should be utilized. These methods will also prove to be the most cost effective. Conclusion: Based on the above tests, the most efficient and cost effective method for delivering oxygen to a portable ventilator is accomplished by introducing the oxygen at the ventilator outlet port using a line adapter or through an IMV bag.

Table 1

FiO2 Analyzed

Volume 100 cc Volume 200 cc Volume 300 cc Volume 400 cc Volume 500 cc

Delivery Method*

Rate 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

6 47 59 70 44 42 69 65 37 37 63 72 30 32 65 69 30 31 57 60 27

10 39 59 65 41 39 39 46 33 35 48 46 29 31 48 50 27 30 39 44 26

15 48 61 63 35 38 39 38 31 34 38 36 28 30 37 39 26 29 34 34 25

20 42 49 54 34 36 34 35 29 33 34 33 27 29 33 34 25 28 31 32 24

*Delivery Methods: 1 = Line adapter at air entrainment port, 2=Line adapter at air outlet port,

3=IMV bag at air outlet port, and 4=connector at circuit wye.

OF-97-024

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