Hi there!  I'd like to know if the Narkomed GS machine requires a low-pressure leak test with a bulb-suction device to the CGO.  I am getting mixed messages about whether or not this check is necessary for THIS machine.  Thanks for any help!

Hi Lenore:  
 
Please see below a reply from Drager in response to an email I sent them about your query.  
 
But first, I'd like to clarify that a leak check of the low pressure sub-system of the anesthesia machine is required in all makes or models,  including the Narkomed GS.  What is being discussed here is whether the Narkomed low pressure sub-system MUST be tested with a suction bulb that generates a sub-ambient (negative) pressure.  The requirement for testing the low pressure sub-system with a suction bulb arises if there is a check valve (often referred to as a Common Gas Outlet check valve) between the fresh gas outlet and vaporizers.    Sem
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Hi Sem,
 
the Narkomed GS does not require the negative pressure leak test since there is no check valve between the fresh gas outlet and the vaporizers.
 
Robert Clark
Care Area Director
Perioperative Care

Hi Lenore:
 
I think I can clarify that one.  
 
First, I am assuming that your question is why is it that Robert Clark stated "the Narkomed GS does not REQUIRE the negative pressure leak test since there is no check valve between the fresh gas outlet and the vaporizers." while Dr. Olympio mentioned that his institution uses "this device" (assumed to mean a  positive pressure bulb sphygmomanometer) to check the Narkomed machines.    
 
If I am correct in re-stating the question, the key words here are positive pressure (meaning a pressure above atmospheric pressure) and negative pressure (sub-ambient pressure or below atmospheric pressure).  
 
The Narkomed GS low pressure leak check can be checked with EITHER a suction bulb (negative pressure bulb sphygmomanometer) OR a positive pressure bulb sphygmomanometer.  That is why Robert Clark stated that the Narkomed GS does not REQUIRE a suction bulb as either type of bulb (suction or positive pressure) can be used to check for a low pressure sub-system leak.  
 
In the case of the suction bulb, pressure increases in the deflated bulb, causing the bulb to reinflate within 10 seconds if there is a leak.  
 
In the case of the positive pressure bulb sphygmomanometer, pressure decreases if there is a leak.  
 
Sem