NMES Role to Prevent Respiratory Muscle Weakness in Critically Ill Patients and Its Association to Changes in Myokines.

Particularly, muscle respiratory wasting will occur early (18 to 69 hours) in up to 60% of patients with mechanical ventilation (MV), leading rapidly to diaphragmatic weakness, which is associated with prolonged MV use, longer ICU and hospital stay, and higher mortality risk. Sepsis and muscle inactivity, derived from sedation and MV use, are key driver mechanisms for developing these consequences, which can be avoided through early physical activation. However, exercise is limited at the early stages of care, where sedation and MV are needed, delaying muscle activation. Neuromuscular electrical stimulation (NMES) represents an alternative to achieve early muscle contraction in non-cooperative patients, being able to prevent local muscle wasting and, according to some reports, has the potential to shorten the time on MV, suggesting a systemic effect through myokines, a diverse range of cytokines and chemokines secreted by myocytes during muscle contraction. However, no studies have evaluated whether NMES applied to peripheral muscles can exert distant muscle effects over the diaphragm, ameliorating its weakness and if this protective profile is associated with myokine's change in ICU patients. This proposal comprises a randomized controlled study of NMES applied twice daily, for three days, compared to standard care (no NMES). Thirty-two patients will be recruited in the first 48 hours after MV and randomly assigned to the control group or NMES group (16 subjects each). Muscle characterization of quadriceps and diaphragm will be performed at baseline (Day 1, before the first NMES session) and after the last NMES session (morning of day 4). Myokine measurements \[IL-1, IL-6, IL-15, Brain-Derived Neurotrophic Factor (BDNF), Myostatin and Decorin\], through blood serum obtained from peripheric blood samples, will be performed just before starting NMES (T0) at the end of the session (T0.5), and 2 and 6 hours later (T2 and T6). These myokine curves will be repeated on days 1 and 3 at the first NMES session of the day. The Control group will be assessed in the same way and timing, except that blood samples will be at T0 and T6. Additionally, functional outcomes such as MV time and ICU length of stay will be registered for all patients at ICU discharge. Standard care won´t be altered.