UAM Maintenance Procedure Video: Calibrating the Ventilator Flow Sensor from Gradian Health Systems on Vimeo.

The ventilator’s flow sensor is a critical and delicate component of the ventilator. It is used to make all the breath measurements. This includes inspiratory and expiratory flows, airway pressures and tidal volume.

The patient flow sensor requires calibration when being used for the first time, periodically every few weeks, if damage is suspected, after cleaning, and if the set volumes and pressures differ from the measurements displayed on the screen.

Calibrating procedure:

1. Disconnect the ventilator drive hose from the ventilator and attach the red plastic adaptor to the 17mm bellows drive taper on the rear of the ventilator bellows assembly. 

2. Connect the patient flow sensor with the flow in the patient direction (blue line closest to patient, clear line closest to ventilator) to first calibrate in the forward direction.

3. Press the “Flow Cal” button.

4. Press “Calibrate Patient Flow”. Press “yes” to start calibration of the inspired flow.

5. When prompted, turn the flow sensor around to calibrate the expired flow and press the “Resume” button. Note: THE VENTILATOR WILL PROMPT YOU TO PUT THE SENSOR IN THE CORRECT ORIENTATION IF IT IS CONNECTED INCORRECTLY

6. When “Complete” press exit.

7. If the calibration fails, perform the procedure again from the beginning.

8. If it continues to fail, a pressure transducer zero offset calibration must be performed followed by the flow sensor calibration.

9. If after doing this it still fails, replace the flow sensor with a new one and perform the flow sensor calibration. If a new sensor fails the calibration please contact Gradian for service.

10. After calibration reconnect the flow sensor to the patient circuit Y piece and place a clean patient bacterial filter ready for the next case.

11. Reconnect the ventilator drive hose between the bellows 17 mm taper and the UAM anesthesia machine ventilator connector.