Variation in blood pressure as a guide to volume loading in children following cardiopulmonary bypass.
OBJECTIVE
Intravascular volume loading is used to optimize cardiac output in children following weaning from cardiopulmonary bypass. Central venous pressure (CVP) is frequently used to titrate fluid administration but it is often misleading in predicting fluid responsiveness. Variation in the arterial pressure waveform is exaggerated in patients with deficient intravascular volume and has been shown to be a good predictor of fluid responsiveness in adults following cardiac surgery. The aim of this study was to compare the measures of variation in blood pressure as a guide to volume loading in children following cardiopulmonary bypass.


METHODS
After ethical approval, we collected continuous real-time measurements from 25 children during volume loading after cardiopulmonary bypass. Subjects with moderate or severe tricuspid incompetence or who did not require volume loading during weaning from cardiopulmonary bypass were excluded from the study. Unstable readings were excluded from analysis. Systolic Pressure Variation (SPV), Pulse Pressure Variation (PPV) and Systolic Volume Variation (SVV) were retrospectively calculated before and after each bolus of fluid. Fluid responsiveness was classified as a change in blood pressure of > or =80 mmHg/L/m(2).


RESULTS
Forty-four boluses were analyzed from the 25 children. Respiratory variables were similar. CVP was a poor predictor of fluid responsiveness and a negative relationship between change in blood pressure and Delta Down was observed. Performance in predicting fluid responsiveness as measured by the areas under the ROC curves were CVP (0.58), PPV (0.67), SPV (0.74) and SVV (0.74).


CONCLUSIONS
Variation in blood pressure was a better guide to volume loading in children than CVP. Delta down was not useful in predicting fluid responsiveness in children with open chests following bypass surgery. SPV and SVV require further testing in prospective clinical trials.
Tran
Henry
H
Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, V6H 3V4, Canada.
Froese
Norbert
N
Dumont
Guy
G
Lim
Joanne
J
Ansermino
J Mark
JM
D000293:Adolescent; D001794:Blood Pressure; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D005260:Female; D006321:Heart / Q000502:physiology; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012372:ROC Curve; D012189:Retrospective Studies; D013314:Stress, Mechanical