Tissue edema, in particular pulmonary edema, increasingly is recognized as a perioperative complication affecting outcome. Management strategies directed at avoiding excessive fluid administration, reducing inflammatory response, and decreasing capillary permeability commonly are advocated in perioperative care protocols. In this review, transpulmonary thermodilution (TPTD) as a bedside tool to quantitatively monitor lung water accumulation and optimize fluid therapy is examined. Furthermore, the roles of TPTD as an early detector of fluid accumulation before the development of overt pulmonary edema and in risk stratification are explored. In addition, the ability of TPTD to provide insight into the etiology of pulmonary edema, specifically differentiating hydrostatic versus increased pulmonary capillary permeability, is emerging as an aid in therapeutic decision-making. The combination of hemodynamic and lung water data afforded by TPTD offers unique benefits for the care of high-risk perioperative patients.