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. The underlying anatomy and circulatory physiology results in increased systemic venous admixture as a result of inferior caval blood being directed into the systemic circulation, and pulmonary venous blood returning to the systemic venous circulation, via collateral circulation. 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. Examples include conditions like patent ductus arteriosus, ventricular septal defect. This can occur when there is an abnormal flow of blood from the right side of the heart to the left side of the heart, bypassing the lungs. Physiologic or total dead space is the sum of anatomic dead space and alveolar dead space. A pulmonary shunt occurs when there is re-diversion of blood from its usual path through pulmonary circulation. Dead space is the volume of a breath that does not participate in gas exchange.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |