CO2 Absorber Replacement During Ongoing Anesthesia

Pre-Change Preparation

The decision to change a CO2 absorber depends on factors such as color indicator change, end-tidal CO2 trending upward, and duration of case remaining, with most modern absorbents changing color when exhausted, typically from white/pink to purple/blue, according to the Anaesthesia guideline 1
If less than 30 minutes remain and ETCO2 is stable, consider continuing with the current canister, as recommended by Anaesthesia 1
Rising ETCO2 despite stable ventilation parameters indicates absorbent failure, as stated by Praxis Medical Insights, but a more relevant guideline is from Anaesthesia, which recommends assessing the need for replacement based on color indicator change and ETCO2 levels 1

Immediately increase fresh gas flow to 5-10 L/min and fully open the APL valve to create a semi-closed system, bypassing the need for CO2 absorption temporarily, as recommended by Anaesthesia, with a strength of evidence level of high 1
Set oxygen flow to at least 5 L/min, with higher flows for larger patients or increased metabolic demand, according to Anaesthesia 1
Fully open the APL valve to allow excess gas and CO2 to escape through the scavenging system, and verify the scavenging system is functioning properly, as stated by MMWR Recommendations and Reports, with a strength of evidence level of moderate 5
Monitor ETCO2 closely, as it should stabilize or decrease with adequate fresh gas flow, according to Anaesthesia, with a strength of evidence level of high 1

Perform a leak test by occluding the patient end of the circuit, squeezing the reservoir bag, and observing for pressure maintenance, as recommended by Anaesthesia, with a strength of evidence level of high 1
Check all connections, ensuring the canister housing, breathing circuit connections, and APL valve are properly secured, according to MMWR Recommendations and Reports, with a strength of evidence level of moderate 5
Verify unidirectional valve function, confirming inspiratory and expiratory valves are moving freely, as stated by MMWR Recommendations and Reports, with a strength of evidence level of moderate 5

For infectious cases, such as COVID-19, the Chinese Society of Anesthesiology recommends replacing CO2 absorbers between cases, and if mid-case replacement is necessary, wear appropriate PPE, treat the used canister as contaminated waste, and minimize aerosolization, according to Anesthesiology (ASA), with a strength of evidence level of high 6
Keep a backup breathing circuit with fresh CO2 absorbent assembled and tested, and during a brief apneic period or hand ventilation, disconnect the old circuit and connect the new one, as recommended by Anaesthesia, with a strength of evidence level of high 1

Never attempt to refill a canister mid-case, only use pre-filled, sealed canisters, as stated by Anaesthesia, with a strength of evidence level of high 1
Maintain continuous monitoring of ETCO2, SpO2, and airway pressures throughout the procedure, according to Anesthesiology (ASA), with a strength of evidence level of high 6
Have backup ventilation ready, keeping a self-inflating bag-valve-mask immediately available in case of circuit failure, as recommended by Anesthesiology (ASA), with a strength of evidence level of high 6
Communicate with the surgical team, informing them of equipment maintenance and potential need to briefly adjust ventilation, according to Anesthesiology (ASA), with a strength of evidence level of moderate 8