Ultrasound Indicators of Nutritional Status and Treatment Outcomes in Surgical Patients in the Intensive Care Unit

The surgical intensive care unit (ICU) provides continuous preoperative and postoperative monitoring of hemodynamically unstable, critically or potentially critically ill patients whose treatment requirements exceed the scope of the competent surgical department. The most common reasons for admission to the ICU are older age, multiple comorbidities, sepsis, demanding and high-risk surgery, and complications during the procedure. The literature increasingly reports that patients' nutritional status and clinical frailty are predictors of ICU treatment duration and outcome. The nutritional status (NS) of patients in intensive care units (ICUs) is assessed using clinical and laboratory indicators, including body mass index (BMI), the clinical frailty score, and hemoglobin and albumin levels. It is quantified by rating scales such as NRS (Nutritional Risk Screening) and MUST (Malnutrition Universal Screening Tool).

Frailty syndrome is defined as a patient's reduced capacity to tolerate changes in physical, physiological, and cognitive body functions. Given the reduction in the organism's physiological reserves, the patient becomes vulnerable to stressors and acute complications associated with the health condition. Patient frailty is correlated with aging, and age is among the most important determinants of frailty. In the intensive care unit, patient frailty is an important predictor of the duration and outcome of treatment, the development of complications during hospitalization, and, as noted above, the consumption of available resources. Assessment of patient frailty enables the appropriate selection of therapeutic procedures and provides overall support to the patient, aiming to achieve optimal treatment outcomes. Patient frailty can be measured using clinical scales; the most commonly used are the Clinical Frailty Scale (CSF) and the modified frailty index (mFI).

Ultrasound is a diagnostic tool that, due to its non-invasiveness and ease of use, is increasingly used to assess the patient's condition and changes during treatment. The most commonly measured ultrasound indicators in intensive care are the presence of effusion or blood in body cavities, flow through blood vessels, and measurement of distance for puncture purposes.

Ultrasound has recently been used to assess the patient's nutritional status by measuring muscle thickness and echogenicity, most often of the upper leg muscles, such as the quadriceps. Muscle cross-sectional area and the thickness of the adipose tissue above it are often measured.

Studies on nutritional status and its relationship with muscle echogenicity in the surgical patient population are rare.