By: Mandi Gerigk CVT, BAS
July 2025
Clinical Specialist, Monitoring and Critical Care
Veterinary anesthesia machines that use rebreathing systems depend on soda lime to absorb exhaled carbon dioxide (CO₂) to maintain safe and effective anesthetic delivery. But without being replaced in a timely or correct manner, soda lime becomes ineffective, putting patients at risk and compromising outcomes.
Failing to replace soda lime when exhausted can result in elevated CO₂ values, leading to anesthetic complications, and in severe cases, patient injury or death. Your team may also struggle to maintain consistent anesthetic depth, especially during longer or more complex procedures.
Capnography is a must for capturing, in real time, whether a patient is rebreathing CO₂. Knowing that exhausted absorbent is a key cause of rebreathing, we need a solid protocol to prevent this before the start of the procedure. A good rule of thumb is to replace soda lime after eight hours of use or once a week, whichever comes first. Even if unused, soda lime becomes exhausted after two weeks of exposure to room air.
Traditional soda lime changes to purple when exhausted, but then reverts to white, making it unreliable as a visual indicator and potentially misleading the next user into unintentional reuse.
Sodasorb® LF offers a permanent, high-contrast color change that provides a clear visual cue for timely replacement. This color change begins immediately with use, transitioning from light to deep purple as use continues. The full progression—from light to deep purple—helps signal when replacement is required. The permanent color change of Sodasorb® LF removes the guesswork of when to replace the soda lime with fresh material. It is a next-generation formulation that reduces reliance on tracking systems that may be overlooked during a busy day.
Sodasorb® LF is formulated to help prevent the degradation of anesthetic gases and reduce the production of hazardous carbon monoxide, compound A and heat buildup caused by desiccation during procedures. Its unique pellet shape reduces caustic dust, making the anesthesia machine easier to clean and reducing resistance to gas flow.
Sodasorb® LF is available in both traditional loose-fill bags and convenient pre-packed cartridges. While most veterinary anesthesia machines are designed to use loose-fill absorbent, not all are compatible with cartridge options. If you are looking for flexibility, the Midmark VMS® Plus anesthesia machine is built to accept both formats, giving your team options for managing and replacing CO₂ absorbent.
This chart illustrates the progression of Sodasorb® LF’s color change. Use it to help guide when the purple deepens
to the point that replacement is recommended.
Soda lime replacement is essential in maintaining safe, effective anesthesia. By combining clinical best practices with tools designed for clarity and consistency, your team can focus on what matters most—delivering exceptional care with skill, confidence and peace of mind.
Sodasorb® is Registered Trademark of Molecular Products US Holdings, Inc.