Are some body areas more important to cover than others?
Some parts of the body lose a disproportionate amount of heat. The head is more vascular and loses more heat than the arm. Body extremities, such as arms and legs, are less vascular than the head but could still be vasoconstricted. This has implications for pulse oximetry and vascular access. For these areas head covers, mitts and boots are available.
What makes AMSORB® PLUS heat up? Does this mean the granules are not working?
The reaction whereby CO2 is absorbed is exothermic (heat is spontaneously generated from the chemical reaction). The amount of heat depends on rate of respiration, fresh gas flow rate and the shape and volume of the absorber canister.
What is the cause of water condensation in the breathing circuit?
This may originate from moisture in the patient’s breath and from water produced by the exothermic reaction of absorption of CO2. It may evaporate as the canister heats up and may condense on cooler parts of the apparatus.
Sometimes exhaustion is indicated by physiological signs or capnometry before the colour changes - why is this?
It may be that the apparatus is not working properly or is incorrectly assembled. There may be channeling of gases through the middle of the absorber canister. Condensed water may be interfering with the composition of sampled gases. Absorbent granules may have absorbed water which is preventing CO2 absorption.
This is determined by capnometry. The absorbent is changed when FiCO2 has exceeded 0.5% volume or 5mmHg. CO2 breakthrough to 0.5% volume or 5mmHg may be associated with colouration of 50% of the total height of the absorber canister.
Completely desiccated AMSORB® PLUS has least ability to adsorb anaesthetic vapour when compared to other absorbents (Knolle, 2002). Note that desiccated AMSORB® PLUS is incapable of absorbing CO2 and therefore will not be in clinical use.
What are the advantages of using AMSORB® PLUS over other available absorbents?
Does not generate Carbon Monoxide under any clinical conditions; does not generate Compound A or any like compounds when used with sevoflurane; does not generate Formaldehyde or Methanol when used with sevoflurane.
Irreversible colour change, when fully exhausted; optimum CO2 absorption; low resistance to gas flow; low dust levels with consistent granule size.