Question

Which of the following typically occurs first when monitoring the earliest physiologic response to breathing 100% O2?

a. substernal chest pain
b. decreased using capacity (DLCO)
c. Decreased lung compliance (CL)
d. Decreased vital capacity (VC)

Answer 1

The earliest physiologic response to breathing 100% O2 typically includes a decrease in lung compliance, which may indicate the lungs are becoming stiffer and less pliable.

Step-by-step explanation:

When monitoring the earliest physiologic response to breathing 100% O2, one of the first observed changes is a decrease in lung compliance (CL). Compliance refers to the lung's ability to stretch and expand. A decrease in lung compliance means that the lungs are stiffer and less pliable, making it more difficult for them to fill with air.

This condition can arise from restrictive lung diseases such as fibrosis, where the lung tissue becomes scarred and stiff. While substernal chest pain, decreased diffusing capacity (DLCO), and decreased vital capacity (VC) can also occur when breathing high concentrations of oxygen, these are typically not the first responses observed.