title: Comparison of bioimpedance and radioisotope methods in the estimation of extracellular water volume before and after coronary artery bypass grafting operation.
abstract: To estimate extracellular water volume (ECW) changes in connection with coronary artery bypass grafting operation, simultaneous ECW estimations by 51Cr-EDTA dilution and whole-body bioimpedance techniques were performed in 15 patients. The assessments of ECW were compared with patients' weighing results. Whole-body bioimpedance-derived ECW correlated significantly with 51Cr-EDTA dilution-based ECW in the pre-operative period (r=0.74; P<0.005); the bias was 0.2 +/- 1.1 l (+/-SD). In the post-operative period, the agreement between these methods was poor, the bias being 0.5 +/- 2.5 l, and no significant correlation between the methods was found (r=0.38; P>0.05). Whole-body bioimpedance-derived ECW changes correlated significantly with weight changes of the patient induced by the operation (r=0.52; P<0.05). 51Cr-EDTA dilution-based ECW changes correlated neither with weight changes (r=0.33; P>0.05) nor with bioimpedance-derived ECW changes (r=0.03; P>0.05). Alterations in radioisotope tracer distribution and loss of it due to blood leakage in the post-operative period were presumed to explain the discrepancy between dilution technique and weighing results. The results suggest that bioimpedance is a useful non-invasive method for assessment of extracellular volume changes induced by coronary artery bypass grafting operations. 51Cr-EDTA dilution-based ECW determination is not suitable in related conditions.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Tampere University Hospital, Tampere, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Kööbi
authors.forename: M
authors.initials: M
authors.lastname: Kähönen
authors.forename: M
authors.initials: M
authors.lastname: Koskinen
authors.forename: S
authors.initials: S
authors.lastname: Kaukinen
authors.forename: V M
authors.initials: VM
authors.lastname: Turjanmaa
mesh_terms: D000368:Aged; D001825:Body Fluid Compartments / Q000502:physiology*; D001835:Body Weight; D002614:Chelating Agents; D002860:Chromium Radioisotopes; D001026:Coronary Artery Bypass; D004492:Edetic Acid; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012680:Sensitivity and Specificity
chemical_list: D002614:Chelating Agents; D002860:Chromium Radioisotopes; D004492:Edetic Acid