Objective: Early aggressive resuscitation is accepted best practice for severe pediatric sepsis. Targeting of therapy to individual hemodynamic patterns is recommended, but assessment of patterns is difficult early in the disease process. New technologies enabling earlier hemodynamic assessment in shock may inform choices for vasoactive drugs in fluid-resistant cases.
Methods: This was a prospective observational study of 30 children with suspected fluid-resistant septic shock (minimum: 40 mL/kg) admitted to the PICU of a tertiary care children's hospital between July 2004 and July 2005. Children were classified according to admission diagnosis (community-acquired sepsis or central venous catheter-associated infection) and assessed within 4 hours after the onset of shock with a noninvasive cardiac output device. Cardiac index and systemic vascular resistance index were measured for all patients. Central venous oxygen saturation was measured for patients with accessible central venous lines at the time of hemodynamic measurements (typically at the superior vena cava-right atrium junction).
Results: Fluid-resistant septic shock secondary to central venous catheter-associated infection was typically "warm shock" (15 of 16 patients; 94%), with high cardiac index and low systemic vascular resistance index. In contrast, this pattern was rarely seen in community-acquired sepsis (2 of 14 patients; 14%), where a normal or low cardiac index was predominant.
Conclusions: The hemodynamic patterns of fluid-resistant septic shock by the time children present to the PICU are distinct, depending on cause, with little overlap. If these findings can be reproduced, then targeting the choice of first-line vasoactive infusions in fluid-resistant shock (vasopressors for central venous catheter-associated infections and inotropes for community-acquired sepsis) should be considered.