Background: Critically ill patients may experience debilitating loss of muscle mass and strength, leading to substantial functional impairments both during and long after hospitalisation. Little is known about what therapies may attenuate deterioration of muscle health (muscle mass and muscle quality) in this setting but nutrition is thought to be important, based on the physiological response to critical illness.~The currently recruiting randomised controlled trial (RCT) Intensive Nutrition Therapy Compared to Usual Care in Critically Ill Adults (ClinicalTrials.gov Identifier: NCT03292237) is the first multi-centre trial to provide an individualised nutrition intervention for the duration of hospital admission in critically ill patients. Combining the most promising and novel bedside techniques for objectively measuring muscle health (bioimpedance technology and ultrasound) with a whole hospital nutrition intervention has never been done before, and will provide crucial data to understand the relationship between nutrition delivery and changes in muscularity from ICU admission to hospital discharge.~Aim: To explore changes in muscle health in response to an individualised nutrition intervention and in association with clinical and functional outcomes, using clinically applicable bedside techniques.~Secondary aims:~In both arms of INTENT to:~Compare longitudinal changes in bioimpedance variables (fat-free mass, normally hydrated lean tissue, extracellular/intracellular ratio, and variables from Cole modelling) to hospital discharge (or day 28)~Compare longitudinal changes in ultrasound variables (mid-upper arm and quadriceps muscle thickness, rectus femoris cross-sectional area, and rectus femoris echogenicity) to hospital discharge (or day 28)~Compare clinical and functional outcomes in patients identified as having low muscularity (assessed by ultrasound) at ICU admission~Investigate the relationship between bioimpedance and ultrasound variables with clinical and functional outcomes at baseline and over the hospital admission (collected as part of INTENT)~Hypothesis: In critically ill patients receiving individualised nutrition care for the duration of hospital admission (censored at study day 28), declines in phase angle and muscle health will be attenuated compared to patients receiving standard nutritional care.
The currently recruiting randomised controlled trial Intensive Nutrition Therapy Compared to Usual Care in Critically Ill Adults (INTENT, NCT03292237) is the first multi-centre trial to compare an intensive, individualised nutrition intervention to standard care for the duration of hospital admission in critically ill patients. INTENT-Muscle, is an observational longitudinal study nested within INTENT. The aim of INTENT-Muscle is to compare longitudinal changes in muscle health (assessed by bioimpedance and muscle ultrasound) in critically ill patients randomised to each arm of INTENT.