Preparing the Anesthesia Machine for CO2 Absorber Change

Step-by-Step Preparation Protocol

The American Society of Anesthesiologists recommends increasing fresh gas flow to 3-10 L/min and ensuring the APL valve is partially open to prevent dangerous pressure buildup and maintain adequate ventilation during CO2 absorber change 1
Increasing fresh gas flow to at least 3 L/min, preferably 5-10 L/min, prevents rebreathing of CO2 during the brief period when the absorber is disconnected or non-functional 1
Higher flows, such as 10 L/min, provide the safest margin, particularly if the change takes longer than anticipated, according to the British Journal of Anaesthesia 2, 3
Ensuring the APL valve is partially open allows excess gas to escape through the scavenging system and is critical to prevent dangerous pressure buildup in the breathing circuit 1, 4

The Anaesthesia society recommends verifying the scavenging system is switched on and functioning before increasing fresh gas flow 1
Confirming the scavenging system is functioning properly prevents operating room pollution due to inadequate scavenging with high fresh gas flows 1
Maintaining continuous capnography monitoring throughout the absorber change is recommended to watch for rising ETCO2 values that would indicate inadequate CO2 removal 5

Performing a pressure leak test by occluding the patient-end and compressing the reservoir bag to 20-60 cmH2O verifies system integrity after absorber replacement 4
Verifying no leaks or obstructions exist in the circuit ensures the new absorber is functioning properly and all connections are secure 4, 1
Gradually reducing fresh gas flow back to the desired maintenance level once the new absorber is confirmed functional and all connections are secure is recommended 1
Modern circle systems can safely operate at flows as low as 1 L/min once the absorber is functioning properly, according to the British Journal of Anaesthesia 2, 3

Failing to increase fresh gas flow before starting the change leads to CO2 rebreathing and potential hypercarbia 1
Forgetting to open the APL valve when increasing fresh gas flow causes dangerous pressure buildup 1
Inadequate scavenging with high flows pollutes the operating room environment 1
Not verifying the new absorber color before installation may result in installing an exhausted canister 4, 1