Lung fluid and protein dynamics during hemorrhagic shock, resuscitation, and recovery

Fluid and protein flow across the pulmonary microcirculation was measured during hemorrhagic shock resuscitation and recovery using either blood or crystalloid as the resuscitation fluid. Fluid filtration rate (Qf) and protein permeability were measured using, as reliable indicators, lung lymph flow and lymph protein content in the unanesthetized sheep with chronic lung lymph fistula. During shock, Qf was maintained, probably because of an increase in pulmonary venous resistance. During resuscitation Qf was significantly increased, but no increase in protein permeability was noted. This increase in Qf was not affected by the type of resuscitation fluid, as the decrease in plasma oncotic pressure with crystalloid was compensated for by a decrease in plasma oncotic pressure with crystalloid was compensated for by a decrease in the interstitial oncotic pressure. Crystalloid resuscitation did, however, increase the Qf response to a fluid challenge in the recovery period, whereas blood resuscitation did not.