Correlation between Sonographic Muscle Measurements of Vastus Intermedius and Rectus Femoris with Nitrogen Balance in Nutritional Assessment of Critically III Overweight and Obese Patients

Abstract

Introduction. Assessing nutritional status has become an essential practice in the critically ill patient, the tools available to the clinician such as anthropometric measurements are inaccurate in obese patients, so it has been necessary to look for other available options such as muscle ultrasound, which has become a novel way to the evaluation of nutritional status and muscle structure of critically ill patients regardless of their body mass index (BMI). Recent studies demonstrate a positive correlation between sonography and total nitrogen balance (TNB) for measuring nutritional status, both of which are considered to be able to assess the nutritional status of overweight and obese patients. Objective. To correlate sonographic muscle measurements of the vastus intermedius (VI) and rectus femoris (RF) with the TNB in the nutritional assessment of critically ill overweight and obese patients. Material and methods. A descriptive, prospective, analytical study in which 30 patients were included. Sonographic measurement of RF and VI muscle thickness was performed simultaneously with TNB on day zero (admission) and five (control). The population was divided into groups according to BMI (overweight, class I obesity, class II obesity, class III obesity). Sonographic measurements were correlated with the TNB measured in the patients. Results. In the initial sonographic measurements, a moderate correlation was found with the TNB at admission. In the group comparison at five days, a strong correlation was demonstrated in the AP diameter of the VI muscle (r=-0.609, p=0.001.) In the initial and control cross-sectional area in cm2 (CSA), a positive correlation was observed (r=0.213 and r=0.258, respectively). Conclusion. There is an inverse correlation between sonographic measurements of RF and VI muscles with TNB in critically ill overweight and obese patients. A positive correlation between CSA of both muscles with the biochemical parameter is reported.