HEMODYNAMIC-RESPONSES TO SHOCK IN YOUNG TRAUMA PATIENTS - NEED FOR INVASIVE MONITORING

Objective: To determine whether early invasive monitoring is necessary in young trauma patients. Design: A prospective study. Setting: Surgi cal intensive care unit (ICU) at an inner city, Level I trauma center. Patients: Thirty-nine patients <40 yrs of age, who required operative therapy for penetrating trauma and who received >6 units of intraoper ative blood. Interventions: Invasive hemodynamic monitoring, with perc utaneous insertion of arterial and pulmonary artery catheters. Vital s igns, hemodynamic and oxygen transport values, and laboratory tests we re obtained at 1, 8, and 24 hrs postoperatively. Oxygen delivery was i ncreased until a normal serum lactate concentration and a state of non flow-dependent oxygen consumption were achieved. Measurements and Main Results: Despite normal heart rate, blood pressure, and urine output, only five (15%) patients achieved an optimized state at 1 hr postoper atively. Of the other 34 patients, two patients achieved an optimized state with volume infusion alone and 32 (82%) patients required inotro pes. Five (12%) patients never achieved an optimized state and died wi thin hours of their arrival to the ICU. Two other patients achieved an optimized state but died of sepsis and organ failure. The other 32 (8 2%) patients achieved an optimized state within 24 hrs and survived. T he hemodynamic values of survivors at 1 hr postoperatively showed a si gnificantly lower pulmonary vascular resistance and serum lactate conc entration, and a significantly higher oxygen delivery and mixed venous oxygen saturation, when compared with the values of nonsurvivors. At 24 hrs postoperatively, survivors also had a significantly lower pulmo nary vascular resistance and serum lactate concentration, and signific antly higher oxygen delivery than nonsurvivors. Survivors' oxygen cons umption was also higher than the oxygen consumption of nonsurvivors. C onclusions: Our data demonstrate that young trauma patients have subst antial but clinically occult myocardial depression after shock, and mo st of these patients require inotropes to optimize and clear circulati ng lactate. Early invasive monitoring is necessary to precisely define the adequacy of the cardiac response and to individually tailor thera py. Patients who do not optimize and clear their lactate within 24 hrs may not survive.