Scavenging System, Capnography, CO2 Absorber Flashcards
1
Q
Scavenging Definition
A
- Collection of excess gases from equipment used in administering anesthesia, or exhaled by patients
- Removal of these excell gases to an appropriate place of discharge outside the working environment
2
Q
NIOSH Recommended Levels of Anesthetic Gases in OR
A
- Volatile Halogenated Anesthetic alone= 2ppm
- Nitrous Oxide= 25ppm
- Volatile Anesthetic with N2O= 0.5ppm
3
Q
5 Basic Components of Scavenging System
A
- Gas collecting assembly
- Transfer means
- Scavenging interface
- Gas disposal tubing
- Gas disposal assembly
4
Q
Picture-Components of a Scavenging System
A
5
Q
Gas Collecting Assembly
A
- Captures excess gases at the site of emission
- Delivers them to the transer means tubing
- Outlet connection 30mm (19mm on older machines) male-fitting
- Size of connections is important so that it doesn’t connect to other components of breathing system.
6
Q
Transfer Means
A
- Exhaust tubing or hose and transfer system
- Conveys gas from collection assembly to the interface
- Tube w/ female-fitting connectors on both ends
- Tubing is short and large diameter, to carry a high flow of gas w/o a significant increase in pressure
- Kink resisitant
- Different from breathing tubes- colored yellow and stiffer plastic
7
Q
Scavenging Interface
A
- Prevents pressure increases or decreases in the scavenging system from being transmitted to the breathing system
- Called the Balancing Valve (Balancing device)
- Interface limits pressure immediately downstream of gas collecting assymbly to between -0.5-+ 3.5cm H2O
- Inlet should be 30mm male connector
- Should be situated as close to gas- collection assembly as possible
8
Q
3 Basic elements of Scavenging Interface
A
- Pressure relief-protects patient and equipment in case of occlusion of system
- Pressure relief limit subatm pressure
- Reservoir capacity- Matches the intermittent gas flow from gas collection assembly to the continuous flow of disposal system
2 Types: Open or Closed
9
Q
Scavenging Interface Picture
A
10
Q
Open Interface
A
- No Valves- is open to the atm via holes in reservoir, avoiding buildup of positive or negative pressure
- Needs Central vacuum system and a reservoir (open canister- size should allow for high waste gas flow)
- Gas enters the system at the top of the canister and travels through a narrow inner tube to the base
- Vacuum control valve can be adjusted-varies the level of suction on the canister/reservoir-must be > or equal to excess gas flow rate to prevent OR pollution
11
Q
Scavenging System Picture
A
12
Q
Closed Interface
A
2 Types:
- Positive Pressure Relief ONLY
- Single PPR valve open when a max pressure is reached
- Passive disposal- no vacuum used, no reservoir bag needed
- Positive Pressure and Negative Pressure Relief
- Pressure and - Pressure Relief valve and Reservoir bag
- Used with an active disposal system- vacuum control valve adjusted so that the reservoir bag is over distended or completely deflated?
- Gas is vented to atm if system pressure exceeds +3.5cm H2O
- Room air is entrained if the system pressure is less than -0.5cm H2O
- A backup negative pressure relief valve opens at -1.8cm H2O if the primary negative-pressure relief valve becomes occluded
13
Q
Gas-Disposal System Tubing
A
- Connects the scavenging interface to the disposal assembly
- Different size and color from the breathing system
- Possitve system hose should be short and wide
- Tubing running overhead ideal to prevent accidental obstruction and kinking
14
Q
Gas-Disposal Assembly
A
- Consists of components used to remove waste gases from the OR
- 2 Types:
- Active- mechanical flow-inducing device moves the gases (produces negative pressure in disposal tubing; must have negative pressure relief
- Passive-pressure is raised above atmospheric by the patient exhaling, manual squeezing of the reservoir bag or ventilator (needs PP)
15
Q
Passive System
A
- Waste gases is directed out of the building via:
- Open window
- Pipe passing through an outside
