VT900A + VAPOR - Testing the respiratory support functions of the anesthesia delivery system

VENTILATOR TEST

Now we move onto testing the ventilation functionality of the anesthesia delivery system.

We can connect the breathing tubes to the inspiratory outlet and the expiratory inlet of the ventilator (or the expiratory valve if it is a single tube breathing circuit). Connect the breathing tube Y-piece to the gas flow inlet of the VT900A. Use a anti-bacterial filter to avoid any contaminants from entering the VT900A. This will help the accuracy and longevity of your test equipment.

Next, connect the test lung to the exhaust port of the VT900A. We are using the Fluke Biomedical AccuLung II. Remember we want to choose a test lung that has its compliance stated, so we can account for that in our measurements. In order to use a test lung, make sure that your VT900A is back in bi-directional breath detect mode.

Turn the ventilator On and allow it to complete its power-up self-test.

You want to make sure your ventilator is operating correctly in every mode. The two main modes of operation are Volume Control Mode and Pressure Control Mode.

Let’s start with Volume Control mode. Volume Control mode is a mode of delivery of controlled breaths limited by the volume of gas per breath prescribed by the physician and adjusted to obtain the best possible gas exchange.

In this example, we are in the breath views screen. We set the tidal volume to 500 ml, set the Breath Rate to 12 breaths per minute, set the I:E ratio to 1:2. You may need to set the equivalent settings for Inspiratory Time to produce a 1:2 I:E ratio.

As with any ventilator performance test, you want to observe that the reading for each relevant parameter is within service manual limits. You do this by comparing the readout on the VT900A to the settings on the ventilator.

If we want to verify the flow, volume, or compare the breathing graphs at any time, we simply need to press Airway, and select which graph we’d like to see to compare against.

We can save the information on our tester at any time by pressing “save” at the bottom of the screen, and then selecting Data, Graph, Recording or Test ID.

You want to repeat this test varying breath parameters according to the service manual. 

The second operating mode is Pressure Control Mode. Pressure Control mode is a mode of delivery of controlled breaths limited by the pressure of gas per breath prescribed by the physician and adjusted to obtain the best possible gas exchange.

In this example, we set the Pressure Level to 18 cmH2O and set the Breath Rate to 12 breaths per minute.

Just as in Volume Control Mode, On the ventilator and on VT900, observe that the reading for each relevant parameter is within service manual limits.

You want to repeat this test varying breath parameters according to the service manual. 

Positive end-expiratory pressure, PEEP, is a pressure applied by the ventilator at the end of each exhaled breath to keep the lung units open. This is key to the treatment of patients with sick lungs and needs to be tested.

In this example, set PEEP to 10 cmH20 and verify that the PEEP is displayed as a new baseline at 10 cmH20.

END SUMMARY

Complete ventilator testing requires that each mode of ventilation be tested, and the manufacturer will have established brand and model specific setting in the testing procedure (found in the service manual of the particular brand and model of ventilator). All ventilator modes must be tested, including patient-assist modes. We will not perform further tests in this brief application example video. We recommend following the manufacturer’s brand and model specific test procedure.

BEFORE RETURNING TO USE

Before returning the ventilator to clinical use, disconnect the breathing circuit, turn the ventilator Off, silence any alarms, and return any settings that were adjusted to their original values.