Phase Angle and Onodera's Prognostic Nutritional Index in critically ill patients

Abstract

Introduction: Assessing severity and nutritional prognosis in critical patients has become increasingly important in recent years, since these parameters are related to morbidity/mortality and used to guide therapeutic options.

Objective: Determine nutritional prognosis through the Phase Angle (PA) and Onodera's Prognostic Nutritional Index (OPNI) and its relationship with severity, hospitalization time and mortality of critically ill patients.

Methods: Descriptive cross-sectional study, involving adult patients hospitalized in an Intensive Care Unit (ICU). Data were collected from the patients' medical records to calculate severity indicators (APACHE II, SOFA and SAPS 3) and determine the length of hospitalization and outcome. Bioimpedance was conducted to calculate the PA, using resistance and reactance data.

Results: A total of 35 patients (26% men and 74% women), with mean age of 55.5 ± 16.7 years, were included. The mortality rate (17%) was similar to that expected by APACHE II and SOFA, but higher than that predicted by SAPS 3. The mean values for the PA (4.2 ± 1.0) and OPNI (38.7 ± 8.3) were lower than the reference values adopted. Individuals with PA < 5.1 exhibited significantly lower reactance and albumin and higher APACHE II and SOFA values, in addition to longer hospitalization time and higher mortality. The PA was inversely correlated with all the severity indicators under study (APACHE II, SOFA and SAPS 3), and the length of hospitalization. By contrast, there was no correlation between OPNI and these parameters, or between PA and OPNI.

Conclusion: The PA proved to be a good tool in assessing nutritional prognosis in critically ill patients. By contrast, more studies using the OPNI with this type of patients are needed.

Keywords: Intensive care. Critical illness. Nutrition. Prognosis.