Bioelectrical Impedance Analysis in the nutritional assessment and prediction of complications in patients undergoing surgery for head and neck malignancies, A pilot observational study

Background Patients with head and neck malignancies are especially vulnerable to developing malnutrition, which has a significant impact on morbidity and mortality. Identification of high risk patients is hence critical for optimising outcomes. Objective It is hypothesised that bioimpedance analysis (BIA) can provide information on nutritional status and risk of perioperative complications in a timely and accurate manner. The study objectives are; to correlate BIA parameters with Subjective Global Assessment (SGA) scores, and determine the association of BIA parameters with common perioperative complications in patients undergoing head and neck surgery. Method This is a cohort study of 61 patients who were admitted for elective head and neck surgery from 2018-2019. Prior to surgery, patients were evaluated in a preoperative multidisciplinary allied health professional clinic for formal SGA scoring. Bioelectrical impedance analysis was performed using the Bodystat Quadscan 4000. One-way ANOVA and Fisher ‘s exact test were performed for associations between SGA and BIA parameters and receiver operating characteristic (ROC) curves were plotted for determination of optimal cut-off values of phase angle and Wellness marker in detecting malnutrition and perioperative pneumonia using Youden ‘s Index (YI). Results 45 males and 16 females with mean ± SD age of 62 ± 1.6 years old were included in the study. Significant differences were observed in Wellness Marker (p=0.004) and phase angle (p=0.006) amongst patients in the 3 SGA categories. BIA parameters (p=0.011 and p=0.032 for Wellness Marker and phase angle respectively) were associated with perioperative pneumonia. No significant differences were observed for other perioperative complications namely surgical site infections, salivary leak/fistula, and flap complications. Conclusion Bioelectrical Impedance Analysis is associated with Subjective Global Assessment and shows promise as a preoperative tool, in conjuction with SGA, to detect malnutrition in patients undergoing surgery for head and neck malignancies and highlight patients at risk of developing perioperative pneumonia.