why is PaCO2 normal in shunt vs Dead space usmle

The measured HCO3 uses a strong alkali that liberates all CO2 in serum, including dissolved CO2, carbamino compounds, and carbonic acid. This calculation frequently results in a discrepancy from the measured due to the blood CO2 unaccounted for by the equation. A derivative of the Hasselbach equation calculates the serum bicarbonate (HCO3) and base deficit or excess. When assessing the acid-base balance, most ABG analyzers measure the pH and PaCO2 directly. Although oxygenation and ventilation can be assessed non-invasively via pulse oximetry and end-tidal carbon dioxide monitoring, respectively, ABG analysis is the standard. PaCO2 is affected by hyperventilation (rapid or deep breathing), hypoventilation (slow or shallow breathing), and acid-base status. PaO2 provides information on the oxygenation status, and PaCO2 offers information on the ventilation status (chronic or acute respiratory failure). ABG analysis assesses a patient's partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2).

An arterial blood gas (ABG) tests explicitly blood taken from an artery. Ī 'blood gas analysis' can be performed on blood obtained from anywhere in the circulatory system (artery, vein, or capillary).

Understanding and use of blood gas analysis enable providers to interpret respiratory, circulatory, and metabolic disorders. Blood gas analysis is a commonly used diagnostic tool to evaluate the partial pressures of gas in blood and acid-base content.

Why is PaCO2 normal in shunt vs Dead space usmle