Effect of elevated PEEP on dynamic variables of fluid responsiveness in a pediatric animal model

Previous studies have demonstrated that stroke volume variation (SVV), pulse pressure variation (PPV) and global end-diastolic volume (GEDV) can be used to predict the response to fluid administration. Currently, little information is available whether application of different levels of positive end-expiratory pressure (PEEP), especially in infants and neonates, affects their ability to predict fluid responsiveness. The aim of our study was to assess the effect of increasing PEEP levels on the predictive value of SVV, PPV and GEDV with respect to fluid responsiveness.

Stroke volume variation and PPV were monitored continously in 22 anesthetized piglets during changing PEEP levels (5 and 10 cmH(2)O) both before and after fluid loading (FL). GEDV was measured by transpulmonary thermodilution; cardiac output and stroke volume (SV) were measured by pulmonary artery thermodilution. A positive response to FL was defined as > or =15% increase in SV.

Fluid loading induced significant changes in all hemodynamic variables except of heart rate and systemic vascular resistance. At PEEP 5 cmH(2)O, SVV, PPV and GEDV significantly correlated with volume induced percentage change in SV, whereas at PEEP 10 cmH(2)O, this correlation was abolished for PPV. As assessed by receiver operating characteristic curve analysis, SVV and GEDV, independent of PEEP level applied, were the best predictors of a positive response to FL [area under the curve: SVV = 0.88; GEDV = 0.80].

In this pediatric animal model, SVV and GEDV were sensitive and specific predictors of fluid responsiveness during increasing PEEP levels.