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

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

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

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

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

CO2 ABSORPTION Chemical reaction of Soda Lime A. CO2+H2O H2CO3 B. 2H2CO3+2NaOH Fast NaCO3+4H20+Heat 2KOH K2CO C. 2Ca(OH)2+NaCO3 slow 2CaCO3+2NaOH=Heat K2CO3 2CaCO3+2KOH CO2 ABSORPTION

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

CO2 ABSORPTION Chemical Reaction of Barium Hydroxide lime A. Ba(OH)2(8H2O)+CO2 BaCO3+9H2O B. 9H2O+9CO3 9H2CO3 C. 9H2CO3+9Ca(OH)2 9CaCO3+18H2O+Heat CO2 ABSORPTION

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

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

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

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

Carbon monoxide has been known to accumulate in absorbers not used with in 24-48 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