Overview

The goal of this quasi-experimental study is to investigate how different body positions, performed through Automatic Lateralization Therapy, affect respiratory drive, ventilation, and pulmonary aeration in critically ill adult patients under mechanical ventilation. The main questions this study aims to answer are:

• Does Automatic Lateralization Therapy, modify respiratory drive, as measured by P0.1, estimated Pmus, and sEMG of the diaphragm and parasternal muscles?
• Is there an association between respiratory drive, ventilation, and pulmonary aeration measured by Electrical Impedance Tomography (EIT) in different body positions promoted by Automatic Lateralization Therapy ?

Does combining Automatic Lateralization Therapy, with Flow Bias improve physiological and functional outcomes compared to Automatic Lateralization Therapy, without Flow Bias?

Participants will:

• Be positioned in different lateralization strategies using Automatic Lateralization Therapy, while under mechanical ventilation;
• Have respiratory parameters and ventilation images assessed by EIT and sEMG;

Participate only during their ICU stay, with no need for additional visits after discharge.

Eligibility

Inclusion Criteria:

• Patients of both sexes will be included;
• Aged ≥ 18 years;
• BMI 18-35 kg/m²;
• Under invasive mechanical ventilation via orotracheal tube for ≥ 24 hours and expected to remain on mechanical ventilatory support for at least 48 hours;
• Sedated (Richmond Agitation-Sedation Scale \[RASS\] -1 to -4);
• Well adapted to protective ventilation strategies in VCV or PSV modes;
• Presenting neural respiratory drive evidenced by a drop in Delta Pocc and/or the presence of assisted cycles;
• Hemodynamically stable (mean arterial pressure between 60-120 mmHg, systolic arterial pressure between 90-180 mmHg, diastolic arterial pressure between 60-100 mmHg, and heart rate between 50-150 bpm) with or without vasoactive drugs at the time of data collection (\> 0.1 to 0.3 mcg/kg/min);
• Respiratory stability, no use of accessory muscles and target SpO₂ achieved;
• No indication for nebulization or heated humidification at the time of collection;
• Positive tolerance test for lateral decubitus positioning;
• Chest circumference of 78-87.9 cm (XS), 88-99.9 cm (S), or 100-111.9 cm (M).

Exclusion Criteria:

• Patients presenting medical restrictions to body repositioning, or to the use of EIT or sEMG;
• Those in therapeutic failure;
• Individuals with spinal cord injury, brain injury, or stroke with a history of functional loss and respiratory impairment prior to hospitalization;
• Neurological diseases affecting respiratory myoelectric conduction;
• History of postural deformities, diaphragmatic abnormalities, or colostomy bag;
• Unstable fracture (lower or upper limbs in proximal regions or thorax);
• Pleural effusion requiring drainage;
• Presence of drains in the thoracic and/or abdominal regions;
• Unstable intracranial pressure;
• Pregnant patients;
• Immediate postoperative period of orthopedic surgeries;
• Use of mucolytics;
• Open ventriculostomy for drainage;
• Uncontrolled agitation;
• Pacemaker or implantable cardioverter-defibrillator;
• Pneumothorax;
• Use of neuromuscular blockers;
• Active tuberculosis;
• Traction devices;
• Active bleeding;
• Suspected or confirmed pulmonary embolism without prior treatment within 24 hours;
• Presence of a large mass in the right and/or left hemithorax;
• History of cardiopulmonary arrest within the past 24 hours under neuroprotection;
• In the total weaning phase from IMV and/or tracheostomy and/or enteral feeding tube and/or scheduled CT scan within the next 6 hours;
• Intolerance to the TLA test (SpO₂ drop \<92% or ≥20% from baseline, need for FiO₂ increase \>50% or ≥20% from baseline, need for PEEP increase, or hemodynamic instability within the first 5 minutes of lateralization testing);
• Those who refuse to provide consent, as determined by the legal representative.