What does WAG stand for?
Waste anesthesia gas
What is the purpose of the scavenger system?
Collect vented gases from the breathing circuit /ventilator and remove them from the OR
What are the two different types of scavenging systems?
What regulation agency determines safe WAG exposure?
National institute of Occupational Safety and Health
What are the NIOSH recommended limits for halogenated agents alone?
< 2 ppm
What are the NIOSH recommended limits for halogenated agents used with N2O?
N2O < 25 ppm
Halogenated < 0.5 ppm
What are the NIOSH recommended limits for N2O alone?
What problems have been linked to overexposure of WAGs?
Increased risk of fetal injury and miscarriages are associated to exposure to these agents
What types of cases will the exposure to WAGs be the greatest?
Pediatric cases, we mask induce allowing more gases into the atmosphere
What size is the transfer tubing in the gas collection assembly?
19 or 30 mm (sometimes yellow in color)
What type of disposal assembly has suction?
Where two tubes lead into scavenger interface?
Tubes from APL and Ventilator relief valve
What is the purpose of the gas disposing tubing?
It carries gas from interface to disposal assembly
What is the purpose of the reservoir bag on the disposal circuit?
If gas enters the disposal circuit faster than it being suctioned out, the gas sits in the reservoir bag (like a holding tank)
What will occur if the reservoir bag is inflated beyond its max capacity?
The scavenging system will allow gas to leak into the operating room through a positive pressure relief valve
What adjusts the amount of suction applied to the scavenging system?
The needle valve
At what pressure does the positive pressure relieve valve open on the scavenging system?
How does the scavenging system prevent negative pressure from affecting the patient’s airway?
Scavenging system has a negative pressure relief valve, this will allow room air to enter into system when suction is excessive
What types of valve is needed for a passive disposal system?
Positive pressure relief (don’t need negative pressure relieve because the system is open)
What type of valves are needed for an active disposal system?
Positive and negative pressure relief
What is the difference between an open and a closed disposal assembly?
An open assembly does not have any valves and communicates openly with the atmosphere
Describe an open disposal assembly.
A hospital vacuum is controlled by a small flow meter, this can physically be adjusted
How does the open disposal system work?
WAGs enter canister, WAGs are heavier than air and will accumulate at the bottom, WAGs carried away by vacuum
How much gas is being removed from the open disposal system when the ball is floating between the two lines?
25L/min into hospital vacuum
What could happen in an open disposal system if the holes were inadvertently covered?
Negative pressure could develop
What must an open disposal system utilize?
Suction, must be an active disposal system and Reservoir bag
Why is it so important for an open disposal system to have suction?
If there was no suction, the gases would escape into the OR
Which disposal system is safer for the patient?
Open disposal system, no risk for barotrauma (no valves to fail)
What disposal system is safer for the provider?
Closed, less risk of WAGs exposure