Acute rehabilitation in critically ill patients can improve post-intensive care unit (post-ICU) physical function. Scientific evidence has considered neuromuscular electrical stimulation (NMES) as a promising approach for the early rehabilitation of patients during and/or after ICU.

Neuromuscular electrostimulation can be an alternative form of muscle exercise that helps to gain strength in critically ill patients with COVID -19, due to the severe weakness that patients experience due to longer MV, analgesia and NMB duration. Thus, the general objective of evaluating the effects of an early rehabilitation protocol on the strength and functionality of patients affected by SARS-CoV-2 variants and specifically compare the effectiveness of NMES associated with the functional rehabilitation protocol(FR). Also, describe demographics, clinical status, ICU therapies, mortality estimates and Hospital outcomes, of every patients admitted in ICU during the observation periods.

Patients in both groups received the functional rehabilitation protocol adapted from the precoce mobilization protocol of Morris et al, 2008. The protocol was defined in 5 stages, with a period between the application of the stages according to the clinical conditions of the patient, in an interval maximum of 24 hours from the beginning of the application of the first stage. The steps included active assisted mobilization exercises, active with Proprioceptive Neuromuscular Facilitation (PNF) method diagonals for upper limbs and bridge exercises, bedside sitting, balance reactions, weight bearing, transfer to an armchair, passive and active orthostatism, static gait and ambulation. The experimental group also received a protocol of neuromuscular electrical stimulation (NMES), applied bilaterally for 30 minutes, using an electrical stimulator with rectangular pulse waves, symmetrical biphasic, applied to the quadriceps femoris and tibialis anterior muscle at the best motor point, activating fast fibers with a pulse time of less than 300 ms and slow pulses with a pulse time of more than 300 ms, with intensity adjusted to obtain visible muscle contraction and/or according to the patient's tolerance.

Inclusion Criteria:

Subjects admitted in ICU for >72hs, undergoing orotracheal intubation and on mechanical ventilation for >48hs, with a diagnosis of Acute Respiratory Distress Syndrome (ARDS) according to Berlin definition secondary to COVID-19, with shock or organ failure, according to the Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (7th Interim Edition) Guideline, and clinical stability:

• mean arterial pressure < 60 mmHg;
• heart rate >60 and <120 beats/minute;
• respiratory rate <30 breaths/minute;
• oxygen saturation ≥ 92%;
• fraction of inspired oxygen (FiO2) ≤0.6;
• absence of vasopressor dose increase
• absence of dysrhythmia (except for chronic atrial fibrillation);
• controlled sepsis;
• hemoglobin (Hb) > 8g m/d, plaquettes >20.000, Glucemia >70 e <180;
• without NMBs

Exclusion Criteria:

• Patients with movement resistance
• Walking without assistance before the ICU (except using a cane)
• Cognitive impairment before acute illness
• Signs of intracranial hypertension, neuromuscular disease (myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré) and stroke; hip fracture, unstable cervical spine, or pathological fracture
• Prior hospitalization (30 days before ICU)
• Readmission to the ICU, within the current hospitalization
• Presence of an implanted cardiac pacemaker or defibrillator, pregnancy, acute myocardial infarction and, for the experimental group (EG), against indications for NMES (deep vein thrombosis, skin lesions, rhabdomyolysis).