Avaliação subjetiva global e bioimpedância elétrica na avaliação nutricional pré-operatória: métodos comparáveis ou complementares?

Abstract

Objective: The objective was to compare subjective global assessment and bioelectrical impedance analysis. We studied 279 patients in a prospective way, who were planned to have an elective gastrointestinal surgical procedure. Design: Patients were evaluated during the first 72 hours after admission. Subjective global assessment was performed according to Detzky and bioelectrical impedance analysis according to Lukaski. It was obtained from bioelectrical impedance the indexes: body cell mass in kg and as current weight percentage, extracellular mass/body cell mass ratio (ECM/BCM), Nae/Ke ratio, phase angle (PA) and electric impedance coeficient (EIC), using values mentioned in literature as cut-off values. Results: There was not a good agreement between subjective global assessment and bioelctrical impedance analysis results. The best agreement was obtained in women, with ECM/BCM above 1,22 and PA. Nevertheless, the bioelectrical parameters average showed that, except body cell mass pencentage, all of them increased or decreased as nutritional status became worse by subjective global assessment. The PA and EIC ROC curves showed a too sensitive or too specific test were resulted by using that cut-off values. No one alternative cut-off values gave an appropiate sensitivity and specificity to the test. However, it's possible to determine high sensitivity and specificity cut-off points to use it as a malnutrition screening test in hospitalized patients. Conclusions: Although they are not comparable methods, subjective global assessment and bioelectrical impedance analysis may be complemental in nutritional assessment of sugical patients.