Rapid flow rates for the resuscitation of hypovolemic shock

Nine dogs were hemorrhaged to approximately 40% of their blood volume and then were resuscitated with a crystalloid solution (Normosol) at various flow rates. Three study groups with three dogs in each group were resuscitated at 15 mL/min/kg (Group 1), 6 mL/min/kg (Group 2), and 4 mL/min/kg (Group 3). Central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), mean arterial pressure, and cardiac output (CO) were monitored during the hemorrhage and the resuscitation from shock. During the infusion of fluids, Group 1 animals demonstrated an elevation of the PAWP of 31 mm Hg and elevation of CVP to 23.2 mm Hg; CO rose to 8.4 L/min. In Group 2 animals CO rose to 6.1 L/min; CVP was 10.5 mm Hg; and PAWP was 25 mm Hg. Group 3 animals had a rise in CO to 5 L/min; CVP and PAWP rose to 4.5 mm Hg and 6.8 mm Hg, respectively. In this experimental shock study, infusion of crystalloids at 6 mL/min/kg appeared to result in an improved physiologic response, although no statistical difference was demonstrated. Further studies are necessary to demonstrate the optimum flow rate for resuscitation of hypovolemic shock using crystalloids.