Anestéziológia a intenzívna medicína 1/2024

Helium and O2 – theory of gas mixing and basics of clinical applications

The authors describe the basic principles of helium (He) and heliox (HeX - breathing gas mixture of helium and oxygen) application in patients with high airway resistance. They analyze the basic biophysical properties of He and HeX, and discuss the theoretical and practical possibilities and advantages of its application, both from a mathematical and technical point of view. Authors describe the most efficient application systems, namely the ventilation circuit with complete rebreathing. From physical perspective, basic principles of gas mixing in a closed (semi-closed) breathing circuit are addressed. Analysis and recommendations of necessary technical equipment as well as patient monitoring connected to HeX therapy is described. In conclusion, HeX treatment may have potential therapeutic advantages to overcome the period of the acute phase of critical illness associated with high airway resistance. This may prevent the need to introduce invasive mechanical ventilation that is associated with multiple risks and is also associated with high treating costs that exceed that of HeX.

Keywords: helium, heliox, COPD, asthma, heliox inhalation, semi-closed breathing circuit