Certified Flight Registered Nurse (CFRN) Practice Exam

Which gas law would most likely affect a patient with suspected pneumonia who has a low SpO2 reading?

1. Graham's law

2. Dalton's law

3. Henry's law

4. Gay-Lussac's law

The correct answer is: Graham's law

The correct answer is closely related to the principles governing the diffusion of gases, particularly in the context of how oxygen is transported and utilized in the body. Graham's law specifically pertains to the rate of diffusion of gases and indicates that lighter gas molecules diffuse more quickly than heavier ones. In the case of a patient with pneumonia, there may be an impairment in gas exchange within the alveoli due to fluid accumulation and inflammation, which can affect the diffusion of oxygen into the bloodstream. This is significant because a low SpO2 reading indicates that the oxygen saturation in the blood is decreased, possibly due to ineffective diffusion of oxygen in the compromised lung tissue. Pneumonia can hinder this process and lead to hypoxemia. Graham's law underscores the importance of understanding how various gas properties affect respiratory function, making it the most relevant gas law in this context. The other gas laws, while relevant to different scenarios, do not directly address the diffusion of gases in the respiratory system as it pertains to the patient's low oxygen saturation caused by pneumonia. For instance, Dalton's law deals with the partial pressures of gases in a mixture, Henry's law relates to the solubility of gases in liquids, and Gay-Lussac's law concerns the relationship between temperature and