Objectives: Fluid bolus therapy is the initial recommended treatment for acute circulatory failure in sepsis, yet it is unknown whether this has the intended effect of increasing cardiac index. We aimed to describe the effect of fluid bolus therapy on cardiac index in children with sepsis.
Design: A prospective observational cohort study.
Setting: The Emergency Department of The Royal Children's Hospital, Melbourne, VIC, Australia.
Patients: A convenience sample of children meeting international consensus criteria for sepsis with acute circulatory failure.
Intervention: Treating clinician decision to administer fluid bolus therapy.
Measurements and main results: Transthoracic echocardiography was recorded immediately before, 5 minutes after, and 60 minutes after fluid bolus therapy. Cardiac index was calculated by a pediatric cardiologist blinded to the timing of the echocardiogram. Cardiac index was calculated for 49 fluid boluses in 41 children. The median change in cardiac index 5 minutes after a fluid bolus therapy was +18.0% (interquartile range, 8.6-28.1%) and after 60 minutes was -6.0% (interquartile range, -15.2% to 3.0%) relative to baseline. Thirty-one of 49 fluid boluses (63%) resulted in an increase in cardiac index of greater than 10% at 5 minutes, and these participants were considered fluid responsive. This was sustained in four of 31 (14%) at 60 minutes. No association between change in cardiac index at 5 or 60 minutes and age, baseline mean arterial blood pressure, fluid bolus volume, and prior volume of fluid bolus therapy was found on linear regression.
Conclusions: Fluid bolus therapy for pediatric sepsis is associated with a transient increase in cardiac index. Fluid responsiveness is variable and, when present, not sustained. The efficacy of fluid bolus therapy for achieving a sustained increase in cardiac index in children with sepsis is limited.