Longitudinal Changes in Muscle Mass After Intensive Care

Background

Rapid and severe muscle loss is a common feature in intensive care [1]. Nutritional support is provided with the intention of preventing excessive muscle protein breakdown, but the evidence that higher energy or protein intake can mitigate muscle wasting in the ICU is limited [2]. A potential explanation to these findings is the proinflammatory and catabolic state often associated with critical illness [3]. As long as a patient remains critically ill, the potential to promote anabolism and recovery may be limited.

It is well-documented that patients discharged from ICU often suffer from poor oral intake during hospital stay [4,5]. Optimizing nutritional support in the post-ICU period may therefore be a simple and cost-effective way of counteracting sarcopenia and improving health-related outcomes [6]. Currently there is a lack of published studies investigating the effect of nutritional interventions on lean body mass after intensive care. This may be due to the cumbersome and resource-intensive methods previously available for measuring body composition. In recent years, bedside ultrasound has become increasingly popular as a research tool for monitoring muscle loss over time. It has been validated against other radiological modalities, is non-invasive and accessible [7].

As there is a lack of literature describing sonographic changes in muscle mass over time in the post-ICU phase, data is needed to support a formal power calculation for interventional studies assessing muscle loss as a primary outcome measure. We therefore plan an observational longitudinal study to describe the change in quadriceps muscle layer thickness over time between ICU and hospital discharge.

Aim

The aims of this project are to 1) estimate the standard deviation of the change in quadriceps muscle layer thickness (MLT) over time, and 2) determine the feasibility of performing a longitudinal follow-up of MLT and energy expenditure in hospitalized patients after ICU discharge.

Hypothesis

In patients discharged alive from the ICU, there is a decrease in mean MLT over time during hospitalization

Inclusion criteria

• ≥18 years old.
• ICU length of stay ≥3 days.
• Expected to be discharged alive within 72 hours.

Exclusion criteria

• Lack of informed consent.
• Limitations in treatment to best supportive care (not expected to survive hospitalization).