Background: Dynamic variables reliably predict fluid responsiveness (FR) in adults, but no data are available regarding their performance in infants. The aim of this prospective study was to assess whether pulse pressure variation (PPV) and stroke volume variation (SVV), in contrast to central venous pressure (CVP) and global end-diastolic volume (GEDV), are applicable in infants undergoing congenital heart surgery and to assess threshold values that may help to guide fluid administration in these patients.
Methods: Twenty-six anaesthetized infants, mean (sd) weight 9.7 (4.3) kg, were studied during closed-chest conditions and changing loading conditions before and after repair of congenital heart disease. Stroke volume index was measured by transoesophageal echocardiography (SVI(TOE)), CVP was measured via a central venous line, GEDV index (GEDVI) was measured by transpulmonary thermodilution, and PPV and SVV were monitored using the PiCCO monitoring system.
Results: Fifteen infants had increased SVI(TOE) with fluid loading ≥15% (responders); 11 infants were defined as non-responders. Analysing the relationship between CVP, GEDVI, SVV, and PPV at baseline with volume-induced percentage change in SVI(TOE), only PPV was significantly correlated with ΔSVI(TOE) both before (r=0.54, P=0.004) and after (r=0.73, P>0.0001). As assessed by receiver-operating characteristic curve analysis, only PPV accurately predicted FR before surgical repair [area under the curve (AUC): 0.79, P=0.01] and after surgical repair (AUC: 0.86, P=0.002).
Conclusions: PPV, in contrast to SVV, CVP, and GEDVI, predicted FR in infants undergoing congenital heart surgery both before and after repair of congenital heart disease.