Leak Test Fail

Do you know if the leak is input primary supplies; Inspiration side & expiration?

Do you have the test card, if so, follow that.

What failure is is?  A vent leak failure or a system leak failure?

If it is a vent leak failure, check the following items...

Patient circuit leak - make sure your patient hoses are good

Flow sensor connection leak - I've seen an older flow sensor have a crack in it - check for discoloration

Pressure sensor tubing - verify it is secure and not pulled loose

Peep valve leak

Inspiratory valve leak

O2 sensor leak - if it has o-rings, make sure there are no nicks in them or they are missing. Be sure to push it down fully into dome.

If it is a System leak failure...

check the absorber(soda lime container)- soda lime dust could cause it not to seal fully

APL valve 

Manual bag and bag arm(Make sure the bag arm screws are secure and the bag arm hasn't twisted loose)

Vaporizers(Make sure they're shut off)

Fresh gas hose(this works loose from moving the COSY assembly and is a cause of a lot of leaks)Make sure the connection is threaded tightly.

Expiratory valve - check if condensation is causing ceramic disc not to seat fully(this also causes Exp. port leakage alarm)

I have the same issue and have attempted to isolate the leaks, which appears to most likely be the ventilator.

I can't get peep calibration to work, and error codes are consistent with low pressure to the ventilator (v062). Fails leak/compliance test as well - both system and ventilator. I understand that system will fail if ventilator fails, so am I right to assume the leak is at the ventilator?

I have put in a new piston membrane and o-ring in the ventilator. I have even swapped out parts of the ventilator with other machines I have that pass leak checks, and still can't get this figured out. All tubes to and from ventilator appear intact and relatively new. What am I missing, or am I on the wrong track?

Any help is appreciated 

Update - 

Switched out COSY and replaced all seals, gaskets, diaphragm etc and still a massive leak somewhere. I can barely get pressure to 15cmH20.

I even changed the filter on the pneumatic reservoir due to a paper out of India showing it can get clogged.

I know it's not the COSY because it's leak tight on other machines.

My current thoughts are:

Ventilator pneumatic pump not getting to pressure?

Do I need to change the piston (machine) diaphragm)? I checked this out and it looks absolutely fine. 

Fresh gas leak? If so, why would the vent leak?

Any help would be great.

Do you have another ventilator to use as a trial. Not likely that the leak is anywhere on the anesthesia machine.

Regards, Michel.

C. Michel Bessette, RRT (Canada #72-659)

Servicios Tecnicos CMB7

644 Merkley Drive,

Ottawa, Canada K4A 1L4

serviciostecnicoscmb7@gmail.com

Mobile: 6138185321

Registered Respiratory Therapist (Canada #72-659)

Bio-Medical Technological Services: Compressed Gas Systems Specialist

Anaesthesia & Hyperbaric Chamber Technologist

Services in: English, Français & Español

Thanks Michel.

I have just retested and done the following:

Installed new patient diaphragm

Swapped in a different ventilator lid

Taken out piston diaphragm and inspected and reinstalled

I still have vent leak more than 350ml/min. Reports on the machine still have V062 and V050 error codes. System has no leaks at 0ml/min.

I do have another ventilator I can swap in to test. I will report back once completed.

In the meantime, any other ideas on where this large leak could be coming from in the ventilator or elsewhere?

 If because of Maintenance maybe the lubricant is too old and must clean the piston correctly and apply a new lubricant but fresh from fabric and the special from the machine factory

Inspect correctly the Piston and the piston wall do not have any kind of dry rest old lubricant

Inspect correctly the Piston and the piston wall do not have any kind of dry rest old lubricant

Update!

Fixed. I swapped out the ventilator with another machine who's ventilator was not leaky, but it was still failing the leak test. So I deduced it wasn't the ventilator, but the pneumatics of the ventilator.

I knew the pump was achieving negative pressure in the chamber of the ventilator, so that left the electronic PEEP valve as the culprit. I inspected it and noticed the wires from the electronic PEEP valve were soldered in place. I took out the entire pneumatic system and when I unplugged the cable from the electronic PEEP valve to the PCB, the wires at the soldering on the electronic PEEP valve snapped off, suggesting they had not been connected for some time.

I resoldered the wires to the electronic PEEP valve, reinstalled and tested and voila! 

Passed leak test first try.

A weird "leak" but I am glad I got to the bottom of it.