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).

Positive pressure ventilation (i.e.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.

Neck extension and jaw protrusion (can increase it twofold).

General anesthesia – multifactorial, including loss of skeletal muscle tone and bronchoconstrictor tone.The ratio of physiologic dead space to tidal volume is usually about 1/3. Alveolar dead space is the volume of gas within unperfused alveoli (and thus not participating in gas exchange either) it is usually negligible in the healthy, awake patient. Anatomic dead space is the volume of gas within the conducting zone (as opposed to the transitional and respiratory zones) and includes the trachea, bronchus, bronchioles, and terminal bronchioles it is approximately 2 mL/kg in the upright position. Physiologic or total dead space is the sum of anatomic dead space and alveolar dead space. Dead space is the volume of a breath that does not participate in gas exchange.

Physiologic dead space vs shunt