carbon dioxide absorption_lw08

8/2/2019 Carbon Dioxide Absorption_lw08

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CARBON DIOXIDE

ABSORPTIONANESTHESIOLOGY NURSING PROGRAMFLORIDA INTERNATIONAL UNIVERSITY

LINDA WUNDER MSN, CRNA


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CO2 ABSORPTION

Circle absorption anesthetic breathingsystem.

Gas flows in a circular pathway throughseparate inspiratory and expiratorychannels.

Components include: fresh gas source,

unidirectional valves, Y-piece connector,corrugated inspiratory and expiratorybreathing tubes, pop-off valves, reservoirbag, and CO2 absorber.


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CO2 ABSORPTION

Functions of CO2 absorption includecomplete removal of Co2 from the circle

system.

Hydroxide(base) neutralizes CO2(acid)

producing end products of H2O,carbonates, and heat(exothermic)


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CO2 ABSORPTION

CO2 absorbent materials consist of amixture of porous granules made up of

base (hydroxide)

Two types of absorbents

Soda Lime (Sodasorb)Barium hydroxide (Baralyme)


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CO2 ABSORPTION

Soda Lime consist of4% NaOH,1%KOH,76% TO 81% CaOH,14% TO 19% H2O

4-8 Mesh size granules-higher the mesh numberthe smaller the granule

Large granules provide small surface area anddecrease resistance to flow

Moisture is added to prevent drying out and silicais added for hardness


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CO2 ABSORPTION

Chemical reaction of Soda Lime

A. CO2+H2O H2CO3

B. 2H2CO3+2NaOH FastNaCO3+4H20+Heat

2KOH K2CO

C. 2Ca(OH)2+NaCO3 slow2CaCO3+2NaOH=Heat

K2CO3 2CaCO3+2KOH


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CO2 ABSORPTION

Barium Hydroxide Lime Consist of:

20% Ba(OH) (8H2O), and 80% CaOH

Small amounts of NaOH and KOH may beadded

Granules are 4-8 mesh

No hardening agent is needed It is slightly less efficient than soda lime

but less likely to dry out


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CO2 ABSORPTION

Chemical Reaction of Barium Hydroxidelime

A. Ba(OH)2(8H2O)+CO2

BaCO3+9H2O

B. 9H2O+9CO3 9H2CO3

C. 9H2CO3+9Ca(OH)29CaCO3+18H2O+Heat


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CO2 ABSORPTION

Indicators are added to absorbent toindicate exhaustion---ethyl violet.

Turns deep purple as PH falls below 10.3.

The color may revert back to white ifabsorbent remains idle(reactivation).

This gives the user a false impression thatthe absorbent is fully functional.


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CO2 ABSORPTION

Each canister holds absorbent material of1000g of granules and has a volume of

1500cc. Each 100g absorbs as much as 15L of

CO2

The average production of CO2 by theanesthetized adults is 12 to 18 L/hr

Therefore each canister last 8-10 hours


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CO2ABSORPTOPN

Air space occupies 48%-55%of canistervolume

Two types of air space exist:

Void space (intergranular) 50%

Pore space (intragranular) 8%-10%

Each canister should be well filled withabsorbent material and shaken to providemaximum function and absorption of CO2


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CO2 ABSORPTION

Soda lime degrades volatile anestheticsagents to some extent

Four time as much of sevoflurane breaksdown in Baralyme as in soda lime

When degraded, sevoflurane also forms

compound A, which has a toxic renal andpulmonary effects.

Therefore it is recommended at least 2l offresh gas flow.


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CO2 ABSORPTION

Carbon monoxide has been known toaccumulate in absorbers not used with in

24-48 hours because of slow reaction withthe volitile agents and absorbents.

Deflurane has the highest accumulation ofcarbon monoxide. It is recommended toflush the system with 100% of O2 for 15mins before use.

carbon dioxide absorption_lw08

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