What typically causes respiratory alkalosis?

Respiratory alkalosis is primarily caused by hyperventilation, a condition in which an individual breathes too quickly or deeply, leading to an excessive loss of carbon dioxide (CO2) from the bloodstream. The decrease in CO2 levels raises the pH of the blood, resulting in alkalosis.

When hyperventilation occurs, the body expels CO2 faster than it can be produced, causing respiratory alkalosis. This can happen in various situations, such as anxiety, panic attacks, or certain medical conditions that increase metabolic demand or stimulate breathing.

The other options do not typically lead to respiratory alkalosis:

• An overdose of analgesics tends to depress the respiratory system, which would generally cause respiratory acidosis due to retained CO2.

• Cardiac arrest usually leads to a cessation of breathing, resulting in respiratory acidosis as well, due to the accumulation of CO2.

• Fluid overload can affect various body systems but does not directly cause respiratory alkalosis; it may even lead to respiratory issues due to pulmonary congestion, potentially causing acidosis instead.

Thus, hyperventilation is the clear and direct cause of respiratory alkalosis in this context.