Emergency Medical Minute

Contributor: Aaron Lessen MD Educational Pearls: What is measured in an ABG/VBG? Blood values for oxygen tension (pO2), carbon dioxide tension (pCO2), acidity (pH), oxyhemoglobin saturation, and bicarbonate (HCO3) in either arterial or venous blood Other tests can measure methemoglobin, carboxyhemoglobin, hemoglobin levels, base excess, and lactate What are they used for? Identification of ventilation/acid-base disturbances. For example: if a patient is in septic shock, oxyhemoglobin saturation can be used to guide resuscitation efforts (early goal- directed therapy) What's the difference between an ABG and VBG? One of the main differences is how the blood samples are collected. Venous blood gas is normally collected from existing venous access such as a central venous catheter. Arterial blood gases must be drawn from an artery, such as the radial artery. Arterial blood draws can be difficult, painful, and contraindicated in many situations. ABGs have traditionally provided more accurate measu