pHCO2

pHCO2 is a term that refers to the partial pressure of carbon dioxide dissolved in a biological fluid, most commonly blood. It is a crucial parameter in the assessment of acid-base balance within the body. The concentration of carbon dioxide in the blood directly influences the pH. Carbon dioxide combines with water to form carbonic acid, which then dissociates into hydrogen ions and bicarbonate ions. An increase in dissolved carbon dioxide leads to a decrease in pH (more acidic), while a decrease in dissolved carbon dioxide leads to an increase in pH (more alkaline). Therefore, pHCO2 is a key indicator of respiratory function. The lungs are primarily responsible for regulating the amount of carbon dioxide in the blood. If the lungs are not effectively removing carbon dioxide, its partial pressure will rise, leading to respiratory acidosis. Conversely, if the lungs are over-ventilating and expelling too much carbon dioxide, its partial pressure will fall, leading to respiratory alkalosis. pHCO2 is typically measured as part of an arterial blood gas (ABG) analysis. Normal pHCO2 levels in arterial blood are generally between 35 and 45 mmHg. Deviations from this range can indicate a variety of respiratory or metabolic conditions.