Oxygen enrichment of the inspired air is provided by the addition of O2 to the BMV suction side reservoir bag at a controlled rate from a user-supplied oxygen concentrator or from a bottled or plumbed medical oxygen supply.
The ventilator control system uses the entered Tidal Volume, Respiration Rate, and oxygen concentration (if from an O2 concentrator) to calculate the oxygen flow required to achieve the user-defined target FiO2. This flow should be set on a rotameter-type oxygen flowmeter or equivalent attached to the oxygen supply. If an oxygen concentrator is used the delivered concentration will also need to be entered on the System Setup Screen.
The measured FIO2 will be displayed on the LycoVent screen after a short delay due to the stored volume of air in the BMV. The response time of the system for a change in oxygen level from 21% to 60% is set out in the table below:
| MV | 3 | 4 | 5 | 6 | 7 | 10 | 14 |
|---|---|---|---|---|---|---|---|
| Total System Response Time (secs) | 100# | 80 | 65 | 60 | 55 | 45 | 30 |
If required the rotameter can then be adjusted to increase or decrease the oxygen flow to the BMV until the measured FiO2 matches the target FiO2. Any subsequent departure of the measured FiO2 above or below user-defined limits will trigger an alarm alerting the operator to adjust the rotameter.