What is likely if a patient is underventilating?

When a patient is underventilating, they are not exhaling enough carbon dioxide (CO2), which leads to an increase in CO2 levels in the bloodstream. This condition is known as respiratory acidosis. The body typically regulates the levels of CO2 by adjusting the rate and depth of breathing; if breathing is insufficient, CO2 accumulates, resulting in a decrease in blood pH and leading to acidosis.

In respiratory acidosis, the kidneys may attempt to compensate by retaining bicarbonate (HCO3-) over time, but the primary immediate concern is the increase in CO2 and the subsequent drop in pH. This physiological process directly contrasts with respiratory alkalosis, which occurs when there is excessive ventilation, leading to decreased CO2 levels and an increase in blood pH.

Understanding the body's response to ventilation changes is crucial in recognizing the signs and managing conditions related to respiratory function. Hence, underventilation is closely associated with respiratory acidosis due to the accumulation of CO2 in the blood.