Which of the following gases would be most helpful with increased airway resistance? Select one: a. heliox b. oxygen c. carbogen d. none of the above

Answer

The correct answer is heliox. Heliox is a breathing gas mixture of helium and oxygen. It is useful in patients with increased airway resistance, such as those with asthma or croup, because it has a lower density than air. Airway resistance depends significantly on the density of the gas moving through the respiratory tract, according to Graham's Law and Reynolds number calculations. Because helium is much less dense than nitrogen (the primary component of air), a heliox mixture reduces the turbulence of airflow and decreases the work of breathing required to move gas through narrowed airways. This results in more laminar flow, lower pressure gradients, and improved ventilation for the patient.