D. Bracco et al., BEDSIDE DETERMINATION OF FLUID ACCUMULATION AFTER CARDIAC-SURGERY USING SEGMENTAL BIOELECTRICAL-IMPEDANCE, Critical care medicine, 26(6), 1998, pp. 1065-1070
Objectives: Bioelectrical impedance analysis (BIA) is based on the phy
sical property of tissues to conduct electrical currents, impedance be
ing inversely related to tissue fluid content. At high frequency, the
electrical current flows across both intracellular and extracellular p
athways, making the assessment of fat-free mass possible while a low-f
requency current flows through the extracellular space. Similarly, seg
mental BIA may be used to assess seg mental body fluid repartition. Th
e aim of this study was to assess fluid accumulation after cardiac sur
gery by multiple frequency segmental BIA, Design: Observational, clini
cal study. Setting: A 17-bed, surgical intensive care unit in a univer
sity hospital. Patients: Twenty-six patients before and after open-hea
rt surgery with cardiopulmonary bypass, Interventions: None. Measureme
nts and Main Results: After surgery, fluid accumulation resulted in a
decrease in whole body and segmental bioelectrical impedance in the ar
m and in the trunk. There was a good correlation between the fluid acc
umulation measured by fluid balance and by whole body or segmental imp
edance changes. The major part (71%) of fluid accumulation occurred in
the trunk. Multiple frequency measurements did not indicate a fluid s
hift between the intra-and extracellular compartments, Conclusion: Car
diac surgery produced a significant decrease in segmental trunk BIA, r
eflecting fluid accumulation at the trunk It!vel.