A Century of Pulmonary Hemodynamics

At the start of the twentieth century, studies of pulmonary hemodynamics were largely confined to measurements of pulmonary arterial pressures in anesthetized, open-chest animals undergoing artificial respiration (1). By then, pressure recording was fairly well standardized, and pressures recorded in animals by different manometric systems were generally accurate and similar in form (2). Outflow pressures, for the calculation of pulmonary vascular resistance and the measurement of left arterial measures, became available at midcentury (3). A leading figure in setting standards for pressure recording was Otto Frank (1865‐1944), a distinguished German physiologist and physician, whose name is well known to circulatory physiologists as one of the discoverers of the Frank-Starling law of the heart. Less familiar, but seminal for the study of hemodynamics, was his role in setting standards for the accurate recording of vascular pressure pulses (4). These standards featured prominently in the subsequent design and application of cardiac catheters for