The role of hypovolemic stress in the production of fat embolism in rabbits. 2. Changes in arterial blood gas levels and static compliance.

The purpose of this study was to assess the possible role of hypovolemia as a factor in the production of impaired pulmonary function in pulmonary fat embolizaiton. Iv vivo static lung compliance was measured by inflating the lungs with known volumes of air and recording the transpulmonary pressure, monitoring intraesophageal pressure as an index of intrapleural pressure. Arterial blood was drawn from the central artery of the ear. Embolization was produced by the intravenous injection of homologous fat cells either as the sole experimental procedure or in conjunction with hypovolemic shock. Two types of shock were studied. In one, 20 percent of the blood volume was removed, producing hypovolemia associated with hemodilution, and in the other a tourniquet was applied to induce hypovolemia and hemoconcentration. The results indicate that embolization is associated with significantly greater impairment of pulmonary function if it develops on a background of shock than if it occurs in an otherwise healthy animal. These pathophysiologic findings parallel the results of a morphologic study.