Body Lateralization and Its Effects on Respiratory Drive, Ventilation, and Pulmonary Aeration in Critically Ill Patients

Official title

Analysis of Respiratory Drive Activation, Ventilation, and Pulmonary Aeration Resulting From Body Lateralization in Critically Ill Patients Under Mechanical Ventilation

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.

Detailed description

Detailed Description:

Critically ill patients under mechanical ventilation frequently develop respiratory complications due to immobility and altered pulmonary mechanics. Automatic Lateralization Therapy has emerged as a promising physiologic intervention to optimize ventilation and reduce respiratory dysfunction in this population. However, its effects on respiratory drive activation remain poorly understood.

Objective:

To evaluate the effects of body lateralization on respiratory drive activation, ventilation, and pulmonary aeration in mechanically ventilated critically ill patients.

Methods and Design:

This is a quasi-experimental, non-randomized physiological intervention study conducted in a controlled ICU environment, following the TREND 2025 Statement Checklist for transparent reporting of non-randomized evaluations. Automatic Lateralization Therapy will be applied with and without Flow Bias, using progressive body tilt angles (0°, 15°, and 30°). Positioning strategies will be personalized based on Electrical Impedance Tomography (EIT) findings to ensure optimal lung recruitment and safety.

Collected data will include:

Clinical and physiological parameters such as respiratory drive (P0.1, estimated Pmus),

Diaphragm and parasternal muscle activity via surface electromyography (sEMG),

Ventilatory mechanics and gas exchange,

Pulmonary aeration and regional ventilation distribution assessed by EIT,

Additional monitoring by lung ultrasound to confirm aeration patterns.

The investigator performing the physiological data analysis will be blinded to the intervention group to minimize bias. Cardiorespiratory safety (e.g., hemodynamic stability, oxygenation) and adverse events will be monitored throughout all procedures.

Expected Outcomes:

The study aims to provide insights into whether body lateralization through Automatic Lateralization Therapy, modulates respiratory drive and improves ventilation efficiency in critically ill patients. It is hypothesized that combining Automatic Lateralization Therapy, with Flow Bias will enhance pulmonary expansion, respiratory drive activation, and gas exchange efficiency compared to Automatic Lateralization Therapy, alone, while maintaining patient safety.

Interventions

• Other Automatic Lateralization Therapy
  During this phase of analysis and intervention related to lateral positioning, patients will be maintained on a Multicare bed (LINET) and subjected to personalized lateral positioning based on the morphofunctional pattern detected by electrical impedance tomography. This positioning will be performed using automatic lateralization therapy, programmed for unilateral or bilateral application, continuously alternating between angles of 0°, 15°, and 30°, maintained for 20 minutes at each position. T
• Other Supine Positioning
  During this analysis phase, patients will be positioned on a Multicare bed (LINET) in the dorsal decubitus position with the head of the bed elevated to 30°. Data will be collected on hemodynamic monitoring, respiratory drive, respiratory mechanics, degree of lung involvement, regional distribution of ventilation and aeration, and gas exchange.

Primary outcome measures

• Respiratory drive parameters: Surface electromyography (sEMG) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Respiratory drive parameter: P0.1 (airway occlusion pressure during the first 100 ms of the inspiratory effort) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes(6 hour 10 minutes)]
• Respiratory drive parameters: Pmus (estimated inspiratory muscle pressure) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Pulmonary ventilation: Ventilation Impedance Change (ΔZ) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Pulmonary aeration: End-Expiratory Lung Impedance Change (ΔEELZ) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]

Secondary outcome measures (12)

• Mechanical response associated with respiratory drive: Diaphragmatic excursion [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Mechanical response related to respiratory effort and lung stress: Dynamic transpulmonary driving pressure [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Driving Pressure (cmH₂O) [Time frame: Unilateral: 140 minutes (2 hour 20 minutes) | Bilateral: 370 minutes (6 hour 10 minutes)]
• Respiratory System Compliance (mL/cmH₂O) [Time frame: Unilateral: 140 minutes (2 hours and 20 minutes) Bilateral: 370 minutes (6 hours and 10 minutes)]
• Airway Resistance (cmH₂O/L/s) [Time frame: Unilateral: 140 minutes (2 hours and 20 minutes) Bilateral: 370 minutes (6 hours and 10 minutes)]
• Arterial pH [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2. Unit: pH units.]
• Partial pressure of oxygen (PaO₂) [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]
• Partial pressure of carbon dioxide (PaCO₂) [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]
• Bicarbonate (HCO₃-) [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]
• Lactate [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]
• Base Excess (BE) [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]
• PaO₂/FiO₂ ratio [Time frame: Baseline; immediately after Sequence 1; immediately after Sequence 2.]

Eligibility criteria

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.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Non-randomized

Model

Crossover

Masking

Double blind

Primary purpose

Treatment

Study locations

Brazil · 1 center

• Hospital Geral Otávio de Freitas - Secretaria de Saúde de Pernambuco — Recife

Publications

• Salluh JI, Soares M. ICU severity of illness scores: APACHE, SAPS and MPM. Curr Opin Crit Care. 2014 Oct;20(5):557-65. doi: 10.1097/MCC.0000000000000135. PMID 25137401
• Dianti J, Bertoni M, Goligher EC. Monitoring patient-ventilator interaction by an end-expiratory occlusion maneuver. Intensive Care Med. 2020 Dec;46(12):2338-2341. doi: 10.1007/s00134-020-06167-3. Epub 2020 Jul 4. No abstract available. PMID 32623476
• Chen H, Liang M, He Y, Teboul JL, Sun Q, Xie J, Yang Y, Qiu H, Liu L. Inspiratory effort impacts the accuracy of pulse pressure variations for fluid responsiveness prediction in mechanically ventilated patients with spontaneous breathing activity: a prospective cohort study. Ann Intensive Care. 2023 Aug 17;13(1):72. doi: 10.1186/s13613-023-01167-0. PMID 37592166
• Silva Junior EFFD, Campos SL, Leite WS, Melo PVS, Lins RAC, Araujo MDGR, Guerino MR. Surface electromyography signal processing and evaluation on respiratory muscles of critically ill patients: A systematic review. PLoS One. 2023 Apr 27;18(4):e0284911. doi: 10.1371/journal.pone.0284911. eCollection 2023. PMID 37104255
• Costa LSP, Reinaux CMA, Junior EFFS, Leite WS, Brandao DC, de Andrade AD, Roldan R, Morais CCA, Campos SL. Physiology of body lateralization on regional lung ventilation and lung volumes in healthy subjects: Within-subjects design. PLoS One. 2025 Oct 30;20(10):e0335622. doi: 10.1371/journal.pone.0335622. eCollection 2025. PMID 41166369
• Zack MB. Pectoriloquy, a retrospective analysis. Chest. 2009 Jan;135(1):8-9. doi: 10.1378/chest.08-2261. No abstract available. PMID 19136401
• Vedrenne-Cloquet M, Ito Y, Hotz J, Klein MJ, Herrera M, Chang D, Bhalla AK, Newth CJL, Khemani RG. Phenotypes based on respiratory drive and effort to identify the risk factors when P0.1 fails to estimate ∆PES in ventilated children. Crit Care. 2024 Oct 4;28(1):325. doi: 10.1186/s13054-024-05103-x. PMID 39367452
• Umbrello M, Formenti P, Longhi D, Galimberti A, Piva I, Pezzi A, Mistraletti G, Marini JJ, Iapichino G. Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study. Crit Care. 2015 Apr 13;19(1):161. doi: 10.1186/s13054-015-0894-9. PMID 25886857

Identifiers

NCT: NCT07323472 · LATLUNG · 92079725.0.0000.5208

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗