1. CARBON DIOXIDE ABSORPTION
ANESTHESIOLOGY NURSING PROGRAM
FLORIDA INTERNATIONAL UNIVERSITY
LINDA WUNDER MSN, CRNA

2. CO2 ABSORPTION Circle absorption anesthetic breathing system.
Gas flows in a circular pathway through separate inspiratory and expiratory channels.
Components include: fresh gas source, unidirectional valves, Y-piece connector, corrugated inspiratory and expiratory breathing tubes, pop-off valves, reservoir bag, and CO2 absorber.
CO2 ABSORPTION

3. Functions of CO2 absorption include complete removal of Co2 from the circle system.
Hydroxide(base) neutralizes CO2(acid) producing end products of H2O, carbonates, and heat(exothermic)
CO2 ABSORPTION

4. CO2 absorbent materials consist of a mixture of porous granules made up of base (hydroxide)
Two types of absorbents
Soda Lime (Sodasorb)
Barium hydroxide (Baralyme)
CO2 ABSORPTION

5. CO2 ABSORPTION Soda Lime consist of 4% NaOH,1%KOH,76% TO 81% CaOH,
14% TO 19% H2O
4-8 Mesh size granules-higher the mesh number the smaller the granule
Large granules provide small surface area and decrease resistance to flow
Moisture is added to prevent drying out and silica is added for hardness
CO2 ABSORPTION

6. CO2 ABSORPTION Chemical reaction of Soda Lime A. CO2+H2O H2CO3
B. 2H2CO3+2NaOH Fast NaCO3+4H20+Heat
2KOH K2CO
C. 2Ca(OH)2+NaCO slow 2CaCO3+2NaOH=Heat
K2CO CaCO3+2KOH
CO2 ABSORPTION

7. CO2 ABSORPTION Barium Hydroxide Lime Consist of:
20% Ba(OH) (8H2O), and 80% CaOH
Small amounts of NaOH and KOH may be added
Granules are 4-8 mesh
No hardening agent is needed
It is slightly less efficient than soda lime but less likely to dry out
CO2 ABSORPTION

8. CO2 ABSORPTION Chemical Reaction of Barium Hydroxide lime
A. Ba(OH)2(8H2O)+CO2
BaCO3+9H2O
B. 9H2O+9CO H2CO3
C. 9H2CO3+9Ca(OH) CaCO3+18H2O+Heat
CO2 ABSORPTION

9. Indicators are added to absorbent to indicate exhaustion---ethyl violet.
Turns deep purple as PH falls below 10.3.
The color may revert back to white if absorbent remains idle(reactivation).
This gives the user a false impression that the absorbent is fully functional.
CO2 ABSORPTION

10. Each canister holds absorbent material of 1000g of granules and has a volume of 1500cc.
Each 100g absorbs as much as 15L of CO2
The average production of CO2 by the anesthetized adults is 12 to 18 L/hr
Therefore each canister last 8-10 hours
CO2 ABSORPTION

11. CO2ABSORPTOPN Air space occupies 48%-55%of canister volume
Two types of air space exist:
Void space (intergranular) 50%
Pore space (intragranular) 8%-10%
Each canister should be well filled with absorbent material and shaken to provide maximum function and absorption of CO2
CO2ABSORPTOPN

12. Soda lime degrades volatile anesthetics agents to some extent
Four time as much of sevoflurane breaks down in Baralyme as in soda lime
When degraded, sevoflurane also forms compound A, which has a toxic renal and pulmonary effects.
Therefore it is recommended at least 2l of fresh gas flow.
CO2 ABSORPTION

13. Carbon monoxide has been known to accumulate in absorbers not used with in hours because of slow reaction with the volitile agents and absorbents.
Deflurane has the highest accumulation of carbon monoxide. It is recommended to flush the system with 100% of O2 for 15 mins before use.
CO2 ABSORPTION