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.
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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.
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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.
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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.