VT900A + VAPOR - Testing the vaporizer on the anesthesia delivery system

Today we are going to show you how to conduct an anesthesia machine test using the Fluke Biomedical VT900A Gas Flow Analyzer and VAPOR Anesthesia Tester. This is a generic test that is representative of an anesthesia machine preventive maintenance procedure but is by no means comprehensive. You must follow OEM recommendations for service and the test procedure described in the service manual.

SETUP

The first component of the anesthesia delivery system we will be testing is the vaporizer.

You will need to set up your VT900A prior to starting the anesthesia machine PM. Significantly reduce your setup time by setting up a Test Profile for your brand and model of medical device. If you are unfamiliar with what a Test Profile is, please refer to the How-to-Use video to view the features of the VT900A and how to set your device up for testing based on your testing preferences. This video can be accessed by going to: www.flukebiomedical.com/gasflow

We need to turn off breath detection on the VT900A. You can do this from “menu” “setup” “breath detect” “off”. This will ensure that we are not measuring breath-by-breath since flow will be continuous.

Another good practice is to zero your airway flow before testing. This will ensure the most accurate results. Do this before connecting to the breathing circuit.

There are two measurement screens we will use on the VT900A. The first is the Airway screen, which will allow us to view the flow, pressure, volume and oxygen concentration through the airway channel. The second is the Breath View screen, which accumulates all of our breath parameters together onto one screen or onto a customized screen using a Test Profile.

The oxygen sensor should also be verified to make sure that you are getting the most accurate results. Do this before a day’s worth of testing. Hook the VT900A up to 100% Oxygen at a flow rate greater than 10 lpm and verify that the oxygen sensor is reading correctly.

VAPORIZER TESTING

Now we will perform an efficacy test of the vaporizer and to do that we will be using VAPOR and the VT900A.

Vaporizer testing confirms that the concentration of anesthetic agent being delivered to the patient is identical to the intended concentration determined by the anesthesiologist.

Before we start vaporizer testing, we should ensure that the gas scavenging system is turned on and functioning properly

Also, many manufacturers ask that you manually inspect the interlock system so that only one vaporizer can be in operation at one time.

The flow rates now need to be verified. Set the flow rate on the anesthesia machine and verify that setting on the VT900A airway screen. In this example, we set the flow to 5 lpm. This is typically controlled with a balance of air, oxygen and nitrous oxide to achieve that flow.

You can also use the ultra-low pressure or ultra-low flow ports on the VT900A to verify the function of your respiratory gas monitor, depending on how the system is setup.

Plug the VAPOR Anesthesia Tester into the VT900A via the connection in the rear. On the Airway screen, you should press the large “Anesthesia” button to access VAPOR. Here you press “On” and the VAPOR will start its warmup process. You can track progress on the screen and can begin testing at “warmup accuracy”, or at “full accuracy” if you need the most accurate readings.

You will need to take your accessory tee and attach it to the fresh gas outlet using either the 15 or 22mm connections. Attach the other end via the quick connect to VAPOR. You may have your own proprietary fittings and be able to attach the accessory tee directly to the common gas hose. Make sure to connect the exhaust end to the anesthesia gas scavenging system.

Do not send agent through the VT900A as it can damage the sensors in the analyzer.

Now we are ready to use VAPOR to verify the anesthetic agent concentration. You will need to measure agent concentration at multiple concentrations and flow rates. In this example, we are measuring Sevoflurane at 5 lpm and 5% concentration. VAPOR will automatically detect the agent being delivered and display it on the screen along with its international color code. The reading on the vaporizer rotometer should match the reading on VAPOR within acceptable tolerances. This procedure should be repeated for all flow and concentration test points listed in the service manual.

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

Vaporizer testing is now complete.