What is outgassing?
Ambient air is dissolved in all liquids used for intravenous (IV) therapy. A portion of this gas will come out of solution in the form of bubbles as the solution is warmed to body temperature in a fluid warming system and/or within the body.
The study below gives an indication as to the volumes of dissolved air in different types of solutions that were warmed to 37°C. Select the study to view in a new window.
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As you can see from this study when common fluids used within a hospital are warmed to body temperature some dissolved air will be released and appear as air bubbles within an infusion set:
Sodium Chloride (0.9%)
Packed red blood cells
Fresh frozen plasma
1.4 ± 0.3 mL/L (n = 6)
3.4 ± 0.2 mL/L (n = 6)
4.8 ± 0.8 mL/L (n = 6)
As per our section on "How is air measured?" 1mL of air within an Agilia Volumat dedicated infusion giving set would fill 14.3cm of tubing.
As such you can see that when infusing fluids that are not yet at room temperature as they have come from a fridge, as an example, it is likely that outgassing will occur and that air will appear within the infusion giving set.
These volumes can be substantially prevented by pre-warming. This could be achieved by allowing the fluids to naturally warm to room temperature before use or by the introduction of a fluid warmer before delivery.
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1 Anesthesia & Analgesia. 123(5):1149–1155, NOVEMBER 2016. Intravenous Air: The Partially Invisible Phenomenon. Varga C, Luria I, Gravenstein N.