Central venous pressure and shock index predict lack of hemodynamic response to volume expansion in septic shock: a prospective, observational study

Abstract

Purpose: Volume expansion is a common therapeutic intervention in septic shock, although patient response to the intervention is difficult to predict. Central venous pressure (CVP) and shock index have been used independently to guide volume expansion, although their use is questionable. We hypothesize that a combination of these measurements will be useful.

Methods: In a prospective, observational study, patients with early septic shock received 10-mL/kg volume expansion at their treating physician's discretion after brief initial resuscitation in the emergency department. Central venous pressure and shock index were measured before volume expansion interventions. Cardiac index was measured immediately before and after the volume expansion using transthoracic echocardiography. Hemodynamic response was defined as an increase in a cardiac index of 15% or greater.

Results: Thirty-four volume expansions were observed in 25 patients. A CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less individually had a good negative predictive value (83% and 88%, respectively). Of 34 volume expansions, the combination of both a high CVP and a low shock index was extremely unlikely to elicit hemodynamic response (negative predictive value, 93%; P = .02).

Conclusions: Volume expansion in patients with early septic shock with a CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less is unlikely to lead to an increase in cardiac index.

Fig. 1

Patient enrollment description.

Fig. 2

Receiver-operating characteristic curves predicting hemodynamic response to volume expansion. Depicted are curves comparing CVP, SI, and the composite of a CVP of 8 mm Hg or greater and an SI of 1 beat min⁻¹ mm Hg⁻¹ or less. The AUCs are calculated, with 95% confidence intervals in parentheses.