Introduction

If a respiratory leak detected error appears during calibration, there are many locations in the respiratory circuit where a leak can occur. Begin testing by splitting the possible leak locations into two major areas, internal and external. Internal leaks occur inside the FPRC controller unit. External leaks occur outside of the controller unit. Once you determine that a leak is not in the controller, concentrate the various parts on the RC table.

Test 1 - Testing the water calibrator

This test should always be performed first to confirm that the water calibrator does not have leaks in the tubing. All valves and fittings that you will connect to the calibrator tubing must also be tested for leaks.

1. Required items:
   1. 1 - Water calibrator and tubing
   2. 1 - 10 ml syringe
   3. 1 - stopcock valve assembly or a Luer “T” fitting
      
      Below is a photo of all parts and a “T” fitting:
      
      
      Here is the assembly with the “T” fitting:
      
      
      Here is the assembly with the stopcock valve:
      
      
      
2. The rest of this procedure will use the stopcock valve pictured above. If you have a different type of valve you must leak test it. We have found that this type of valve can be the source of leaks.
3. Once the parts are assembled, position the blue valve as shown below. Make sure the syringe and calibrator tubing are connected to the valve tightly.
   
   
   
   
4. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards. Please note that you will make the same observation every time you leak test various components. The water level should always hold steady and it should not drift up!
   
   
   
   
5. Turn the blue valve to open the port on the stopcock. The pressure should be released and the water level should rise to the top.
6. If no leaks were found in the calibrator tubing assembly and the fittings you can proceed to the remaining tests.

Test 2 - Checking the FPRC controller unit for internal leaks by swapping controllers

1. If you own more than one FPRC system you can easily test for internal controller leaks by swapping the controller with a different controller that successfully calibrates.
2. Remove the controller from the site that fails calibration and replace it with the controller from a site that passes calibration.
3. If the site that originally failed still continues to fail with the new controller, the issue is probably with the external parts and connections.
4. You can double check this test by also testing the controller from the site that failed calibration on the table of the site that passed calibration. If the site that passed calibration fails with the controller from the site that failed calibration, the issue is with the controller. In other words, the problem followed the controller.
5. If you determine the issue is internal to the controller and the controller fails calibration on both sites, please confirm this by performing the next test.
6. If you only own one controller, continue to the next test.

Test 3 - Checking the FPRC controller unit for internal leaks with the water calibrator

1. Turn off the power to the FPRC controller unit
2. Plug the green exhaust port and attach the calibrator tubing assembly to the blue expiration port as shown below. Please note that this photo shows the “T” fitting, not the stopcock valve. You may have to use a different fitting to connect the stopcock valve assembly if you are using it.
3. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
   
   
   
   
4. Next, move the calibration tube to the red inspiration port. Remove the plug from the green exhaust port.
5. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
6. If the water drifts upwards during either of these tests, contact DSI technical support. The controller will need to be shipped to DSI for repair at 1-800-262-9687.

Test 4 – Checking the entire external respiratory circuit for leaks

Before starting this test, please look over the picture below for common leak points in the respiratory circuit. A leak at any of these locations can cause the calibration to fail.

To test the entire external circuit for leaks:

1. Setup the hardware as shown below. The point from the top of the red inspiration tube to the manifold will be tested.
   1. Remove the red inspiration tubing from the inspiration port on the controller
   2. Attach the calibration trach tube to the ports inside the chamber. Set it up just as though you were going to calibrate the system.
   3. Attach the calibrator tubing and syringe to the port on the side manifold where the blue expiration tub usually connects.
      
      
2. Hold your finger over the end of the red inspiration tubing as shown above.
3. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
4. If the water level drifts, there is a leak in the external circuit. Once you have determined this, you should begin testing the individual parts by removing one component at a time testing for leaks with the calibrator.

Test 5 – Aerosol block to the manifold

1. Remove the red inspiration tubing from the aerosol block and setup everything else as described in Test 4 above.
2. Plug the hole in the aerosol block where the red inspiration tube was connected.
3. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
4. If there is no leak, the red inspiration tube is the issue. Swap the tubing and test again.
5. If the water level still drifts, the leak is between the aerosol block and the manifold. Continue testing…

Test 6 - Aerosol connector tube to the manifold

1. Remove the aerosol block and the red inspiration tube. Leave the small acrylic tube that connects the aerosol block to the manifold connected to the manifold. Setup everything else as described in Test 5 above.
2. Block the acrylic aerosol block tube with your finger.
3. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
4. If there is no leak, the aerosol block is the issue. Try a different aerosol block and check that the aerosol head is connected to the top of the aerosol block tightly. Test again.
5. If the water level still drifts, the leak is between the aerosol block connector tube and the manifold. Continue testing…

Test 7 – The manifold

1. Remove the acrylic aerosol block connector tube, the aerosol block, and the red inspiration tube.
2. Block the trach port on the manifold with a luer plug. See the picture below.
3. Inject enough air into the calibrator so the water level in the middle tube descends to about ½ way down. Hold the volume steady with your thumb. The water level should hold steady and it should not drift upwards.
4. If there is no leak, the acrylic aerosol block connector tube is the problem. Replace the tube.
5. If the water level still drifts, the leak is in the manifold.
   1. Try changing the calibration trach tube that is inside the chamber. This may be the location of the leak. Test again after replacing.
   2. Also check inside the manifold where the calibration trach tube connects to the two ports inside the chamber. There are small black rubber O-rings in the ports. They may be missing or they may not be inserted straight. Test again.
   3. Check all of the luer plugs that are inserted in the accessory ports on the manifold. Make sure they are tight. Test again.
6. If the manifold is still leaking, it may be damaged. The unit will need to be shipped to us for repair. Please call DSI support at 1-800-262-9687.