How much more diffusible is carbon dioxide compared to oxygen?

Carbon dioxide is approximately 20 times more diffusible than oxygen due to its molecular characteristics and the principles of gas behavior. The diffusivity of a gas is influenced by factors such as its molecular weight and solubility. Carbon dioxide (CO2) has a smaller molecular weight compared to oxygen (O2) and possesses a higher solubility in bodily fluids.

When considering diffusion, Fick's law indicates that the rate of diffusion is proportional to the difference in concentration and inversely proportional to the square root of the molecular weight. This means that for gases, lighter gases will diffuse more quickly than heavier ones. In practice, this characteristic enables carbon dioxide to diffuse rapidly across biological membranes, such as the alveolar-capillary membrane in the lungs, facilitating efficient gas exchange.

The significantly greater diffusibility of carbon dioxide plays a critical role in various physiological processes, including respiration and the maintenance of acid-base balance within the body. Understanding this difference is essential for healthcare professionals, especially in critical care settings, where effective gas exchange is vital for patient management.