Ângulo de fase (AF°) por bioimpedância como marcador das modificações clínicas e metabólicas em cirurgias oncológicas do trato digestivo

Abstract

Background: When it comes to the nutritional status of cancer patients, cancer-related weight loss is well known and, because it contributes to worse clinical outcomes, reduced tolerance to antineoplastic drugs and worse prognosis. There are currently a large number of parameters and direct and indirect indicators of the nutritional status used to evaluate cancer patients, but we do not yet have a gold standard. One of the possible markers, however, that is not very well evaluated or applied in the surgical practice, can be the phase angle (PA). Objectives: To evaluate the clinical and metabolic changes using PA and SPA by electroimpedance (BIA) in patients with elective digestive surgery - esophagus and esophagus. Method: A comparative, observational, analytical study for the evaluation of the short-term three-stage diagnostic test (pre, peri and postoperative) using other methods of nutritional assessment of the clinical practice (biochemical), compared to the phase- PA and SPA, aiming at the detection of malnutrition and prognosis of postoperative mortality at 30 days of follow-up. Results: The study was composed of 101 participants. Operated for total esophagectomy, subtotal and total gastrectomy. The majority were male 52.5% (53), and> 60 years (48.4%). The age range ranged from 38-80 years. The PA observed during the three phases of the study varied and was statistically significant (p <0.001) between peri (second phase) 4.58 ± D1.18; and postoperative (3rd phase), 4,14 ± Dp1,13 However, in the three phases, the patients showed a mean ± SD of less than 5. The SPA in the different phases of the follow-up changed, varying from -1,28, ± Dp = 1.44 to -2.20, ± Dp = 1.78, and were statistically significant (p <0.001). The ideal cutoff value of PA derived from the ROC curve obtained was 4.14º, associated with malnutrition, showed sensitivity, specificity, positive predictive value and negative predictive value of 76%, 72.4%, 71.4% and 73.1% %, respectively. AUC showed great accuracy among well-nourished and malnourished patients (AUC = 0.76 P = 0.001). For the death, analysis of the area under the PA curve in the postoperative period was important (AUC 0.907, 95% CI: 0.882 As far as the analysis of the area under the PA curve for postoperative infection was important (AUC 0.820, 95% CI: 0.811-0.921), and P-value (P = 0.002) was demonstrated by a very short confidence interval), P-value (P = 0.0002). Conclusions: Our results confirm that malnutrition is associated with lower levels of PA and SPA, and that both PA and SPA present high accuracy in nutritional screening, implying be a useful marker for prognosis of death and infection in the study population.