Optimization of Initial Fluid Challenge by Cardiac and Lung Ultrasound in Patients With Sepsis

Initial sepsis treatment requires fluid challenge (FC). While the Surviving Sepsis Campaign (SSC) indicates a fixed 30 ml/kg volume, there is concerns on the efficacy and safety of this volume.

Actually, the required volume is highly dependent of cardiac and pulmonary comorbidities, infection focus localization and intensity. The importance of the initial volume is crucial: if too low, it could not restore the hemodynamic status, if too high, it could induce a lung edema responsible for an increased morbidity and mortality.

Cardiac Ultrasound (US) has demonstrated its efficacy to approach cardiac output by measuring the velocity-time integral (VTI) in the aortic chamber and its variations induced by the FC. While the VTI induced variation by a 500-ml FC in 20 min is above 10%, the patient is still fluid responsiveness and FC has to be continued. Conversely, when the variation is below 10%, FC has to be stopped.

Lung Ultrasound can detect a sub-clinical pulmonary edema before oxygenation degradation by visualization of diffuses B lines. The combination of both techniques is thus able to individualize the actual needed FC volume.

In patients with sepsis as defined by SEPSIS-3 and with hypotension (MAP < 65 mm Hg or lactate > 2 mmol/l), the FC of saline serum is individualized by the US technique. The volume is compared with the fixed 30 ml/kg.