The Relationship Between Pulmonary Vascular Resistance (PVR) and Lung Volume

(From Slinger P, Darling G. Preanesthetic assessment for thoracic surgery. In: Slinger P, ed. Principles and Practice of Anesthesia for Thoracic Surgery. New York, NY: Springer; 2011:11-34, with permission.)

PVR is lowest at functional residual capacity (FRC) and increases as the lung volume decreases toward residual volume (RV), owing primarily to the increase in resistance of large pulmonary vessels. PVR also increases as lung volume increases above FRC toward total lung capacity (TLC) because of an increase in resistance of small interalveolar lung vessels.