Intravenous Air: The Partially Invisible Phenomenon

Area of Science:

• Medical Devices
• Fluid Dynamics
• Biomedical Engineering

Background:

• Ambient air dissolves in intravenous (IV) fluids, forming bubbles upon warming to body temperature.
• This outgassing occurs in fluid warming systems and within the body during IV therapy.
• Quantifying dissolved gas release is crucial for IV safety.

Purpose of the Study:

• To quantify the proportion of dissolved air that outgasses from crystalloid and blood products during warming.
• To assess the impact of temperature changes on dissolved gas in IV solutions.
• To evaluate methods for preventing gas bubble formation during IV administration.

Main Methods:

• Calculated theoretical dissolved air volumes using Henry's Law for NaCl, packed red blood cells, and fresh frozen plasma.
• Experimentally measured outgassed gas volumes during warming of these fluids to 37°C.
• Expressed measured gas volumes as a fraction of theoretical outgassing volumes.

Main Results:

• Measured outgassing was 1.4 mL/L for NaCl, 3.4 mL/L for PRBCs, and 4.8 mL/L for FFP.
• These volumes represented 30% (NaCl), 41% (PRBCs), and 44% (FFP) of theoretical outgassing.
• Prewarming solutions to 37°C significantly reduced outgassing.

Conclusions:

• A significant amount of dissolved gas outgasses from IV fluids upon warming to body temperature.
• Outgassing is expected to occur within the body, posing potential clinical risks.
• Prewarming IV solutions is an effective strategy to prevent substantial gas outgassing.