Ace the CPFT Challenge 2026 – Breathe Easy with Pulmonary Success!

When blood temperature decreases, it affects the gas exchange dynamics and the acid-base balance in the body, leading to several physiological changes.

A decrease in blood temperature generally results in an increase in the solubility of oxygen in the blood. As a result, the partial pressure of oxygen (PO2) tends to increase because the body can carry more oxygen in solution due to the lower temperature. However, the binding affinity of hemoglobin for oxygen also increases at lower temperatures, which can partially counter this effect under certain conditions. In terms of carbon dioxide, lower temperatures can lead to increased carbon dioxide retention due to decreased metabolic activity, which may cause a rise in the partial pressure of carbon dioxide (PCO2) as cellular respiration slows down.

This combination ultimately leads to an increase in pH, as the accumulation of carbon dioxide (which forms carbonic acid when dissolved in blood) typically lowers pH. However, a decrease in temperature may slow down metabolic processes causing a relative decrease in production of carbon dioxide, which can contribute to a higher pH in this context.

Thus, the correct answer reflects these changes: with decreased blood temperature, the partial pressure of oxygen might decrease due to altered hemoglobin affinity, carbon dioxide levels could decrease due