The effect of a single session of whole-body neuromuscular electrical stimulation (NMES), with or without subsequent intake of a protein bolus, on whole-body protein turnover in sedated intensive care unit (ICU) patients

Intensive care unit (ICU) stay is accompanied by muscle wasting (i.e. the loss
of muscle proteins) and ICU-acquired weakness (ICU-AW), which lead to increased
time of mechanical ventilation, morbidity, negative post-ICU consequences and
an overall decreased quality of life (QoL). The building blocks of our muscles,
called amino acids, are primarily acquired through dietary intake. A
fundamental cause for ICU-induced muscle wasting is an impaired response to the
anabolic properties of dietary protein. Neuromuscular electrical stimulation
(NMES) could stimulate muscle amino acid metabolism and alleviate some of these
negative consequences by reintroducing (involuntary) muscle contractions via
small electric currents. Previous research has shown that NMES of the
quadriceps muscle alleviated muscle wasting in sedated patients. At present,
the effects of a whole-body NMES approach in combination with timed protein
intake on amino acid metabolism in ICU patients remain unknown.

To examine the effect of a single session of whole-body NMES, with or without
subsequent protein intake, on whole-body protein turnover

Randomised, placebo-controlled design with three parallel groups

A single test day during which participants will either receive sham-NMES
followed by standard enteral nutrition (CON), whole-body NMES stimulation
followed by standard enteral nutrition (WB-NMES), or whole-body NMES followed
by a bolus of 20g protein (WB-NMES+PRO). Continuous intravenous infusion of
labelled amino acids will be combined with repeated blood samples. Doppler
ultrasound measurements will be performed before blood sampling to determine
forearm amino acid and glucose balances.

We will use the arterial and central venous lines that have already been
inserted for blood drawing. A cannula will be placed in the elbow crease to
collect blood. If not in situ, another cannula will be placed for stable
isotope infusion. Insertion of the catheters in a vein is comparable to a
routine blood draw, and the only risk is a small local hematoma. The standard
nutrition provided is part of the routine care in the ICU, so it poses no extra
risks. Short fasting periods are common in this population and pose no risks.
NMES has been applied to critically ill patients by ourselves and others, and
it has been proven safe when applied by trained staff. The protein bolus is
commonly used in current practice in ZGV. The labelled, non-radioactive amino
acid tracers that will be infused intravenously are produced under sterile
conditions according to GMP standards and routinely used in human skeletal
muscle metabolism research.