Anatomical dead space: This is the volume of air in the conducting airways that does not participate in gas exchange.In other words, it’s the volume of air that is inhaled during breathing but doesn’t contribute to the oxygenation of blood. What is Dead Space?ĭead space refers to the portion of each breath that does not participate in gas exchange because it remains in the conducting airways or reaches alveoli that are not perfused. Small shunts might not significantly impact oxygen levels, but larger shunts can cause severe problems, including shortness of breath, cyanosis, and other signs of low oxygen levels. The effect of shunts on the body is dependent on their size. This results in deoxygenated blood being sent into the systemic circulation, which can lead to hypoxemia, a condition where your body or a region of your body is deprived of adequate oxygen supply. This can occur due to various reasons, such as when blood vessels bypass the lung tissue (anatomical shunt), or when parts of the lungs are perfused, but not ventilated, leading to a lack of gas exchange (physiological shunt). Uworld says this is v/q mismatch but that gets me confused cause why wouldn't a vent defect give v/q mismatch.A shunt refers to a condition where blood passes from the right side to the left side of the heart without being oxygenated in the lungs. That's why you will see a drop in PaO2 in PE(minor). So this one is tougher but: Let's assume you have a well ventilated alveoli, when there is poor oxygen content, vasculature will constrict and redistribute this blood to other alveolar however it will overwhelm the capacity of extracting oxygen into blood - so adding oxygen will help. Dead space/physiologic dead space/V/Q mismatch to inifinty.I remember total pulm shunt as if pulm art partial pressure = pulm vein partial pressure, shunted, basically just bypassed lungs.

These alveolar are already extracting maximum oxygen, adding more would not help. Lets assume this kid have some alveoli that are working.

pulm shunting - ventilation defect V/Q 0, perfusion intact.

So this is my understanding of the topic and I might be wrong so please correct me if thats the case:

Left right shunt vs dead space