Pressure injury (PI) is characterized as damage to the skin and/or underlying tissues resulting from sustained pressure or a combination of pressure and shear forces between the patient and the support surface. Prolonged pressure is a well-established risk factor in the development of PIs. Frequent repositioning and routine patient care have been recognized for decades as integral components of PI prevention and treatment protocols.

The duration of interface pressure is as critical as its magnitude. When interface pressure exceeds the mean capillary blood pressure, blood flow can be compromised, leading to ischemia in affected areas, which may progress to necrosis if sustained over time. Furthermore, it is widely accepted in the literature that tissue becomes at risk when interface pressure exceeds 30 to 32 mmHg.

In this context, continuous lateral rotation therapy (CLRT) offers a potential alternative for managing critically ill patients. CLRT involves continuous mechanical rotation of the patient in the lateral plane. However, its effects on skin integrity remain poorly understood. Despite the rationale behind and widespread recommendation of repositioning, the lack of robust evaluations on how repositioning impacts interface pressure creates uncertainty, underscoring the need for high-quality trials to assess different strategies for implementation.

Although lateralization is a pragmatic strategy for preventing pressure injuries, its use in critically ill patients requires an integrated assessment of respiratory, hemodynamic, and gastroesophageal effects. Therefore, this study proposes an innovative approach by evaluating, for the first time, the effectiveness of automated postural change with simultaneous monitoring of tissue integrity, pulmonary function, cardiovascular stability, and gastroesophageal protection. The aim is to optimize pressure injury prevention, improve pulmonary mechanics, ensure hemodynamic stability, and preserve gastroesophageal safety in critically ill patients.

The objective of this study is to evaluate the effectiveness of Automated Lateral Rotation Therapy in reducing interface pressure between the patient and the support surface, considering different head-of-bed elevations, in mechanically ventilated patients. This is a multidimensional approach, assessing the effects on respiratory, hemodynamic, and gastroesophageal parameters.

This is a single-center, intra-individual crossover randomized clinical trial, using a Latin square allocation model, conducted in an intensive care unit.

The study will compare the effects of automated platform lateralization at 15 degrees and 30 degrees, combined with a 10-degree head-of-bed elevation, to the supine position with a 30-degree head-of-bed elevation, focusing on the reduction of interface pressure. Lateral tilting will be performed to both sides (right and left) according to prior randomization. Each position will be maintained for 10 minutes, followed by a 10-minute washout period in the supine position before transitioning to the next condition.

Additionally, after completing the crossover assessments, a subgroup of six patients will undergo an extended monitoring phase. In this step, the lateralized position at 30 degrees with a 30-degree head-of-bed elevation will be maintained for two continuous hours on each side (right and left) to assess the temporal evolution of interface pressure, determining whether pressure values remain stable or tend to increase over time.

The intervention will be conducted using the Linet Multicare bed, equipped with the Symbioso mattress, which features Continuous Low Pressure (CLP) and Microclimate Management (MCM) modes. This system enables manual or automated lateral tilting of the entire bed platform up to 30 degrees on the axial axis. The CLP mode provides automatic, continuous low-pressure redistribution, minimizing interface pressures regardless of weight distribution or patient movement. The MCM mode includes a vapor-impermeable cover that reduces skin moisture and heat, supporting skin integrity and preventing maceration.

Monitoring Procedures Interface pressure monitoring will be performed using the ForeSite Intelligent Surface (Xsensor, Canada), a sensor network embedded in a mattress cover composed of 6136 sensing cells distributed over an area of 762 by 1880 millimeters, with a spatial resolution of 31.75 millimeters. The system provides continuous pressure acquisition at 3 Hz, operating in the range of 5 to 200 mmHg (0.7 to 36.6 kPa), with an accuracy of plus or minus 2 mmHg. During the protocol, interface pressure will be monitored continuously with real-time visual feedback displayed on a bedside LCD monitor, allowing visualization of pressure redistribution throughout the interventions.

Pulmonary monitoring will be conducted using the ENLIGHT (Timpel, model 2100, Brazil), which utilizes a 32-electrode belt placed around the thorax at the mid-axillary line to provide real-time monitoring of ventilation distribution through electrical impedance tomography (EIT).

Hemodynamic monitoring will be performed using the FloTrac system coupled with the EV1000 platform (Edwards Lifesciences, Irvine, California, USA), connected to a peripheral arterial catheter, enabling continuous measurement of cardiac output, cardiac index, stroke volume, stroke volume variation, and blood pressure parameters.

Gastroesophageal pH monitoring will be carried out using the AL-4 pH monitoring system (ALACER, Brazil), which includes an antimony pH probe with an external reference electrode placed on the patient's thoracic skin to continuously measure esophageal pH levels.

Primary Hypothesis Automated Lateral Rotation Therapy promotes a reduction in interface pressure, assessed by peak pressure, mean pressure, and the absolute count of sensors recording pressure above 40 mmHg. Additionally, it is hypothesized that the extent of this reduction varies depending on the degree of lateral tilt and head-of-bed elevation, with lower degrees potentially being more effective for pressure redistribution.

Secondary Hypotheses Automated lateral positioning improves respiratory mechanics, contributing to better ventilation and oxygenation.

Adverse hemodynamic effects are minimized when using controlled tilt angles. Automated lateral rotation does not increase the incidence of gastroesophageal reflux.

Primary Outcome Reduction in peak pressure in the sacral region.

Secondary Outcomes Peak pressure mean pressure in the occipital, scapular, and calcaneal regions. Mean pressure in the sacral, occipital, scapular, and calcaneal regions. Number of sensors with pressure above 32, 40, and 60 mmHg in the sacral, occipital, scapular, and calcaneal regions.

Respiratory parameters including static compliance, driving pressure, oxygenation, and volumetric capnography.

Hemodynamic parameters including heart rate, blood pressure, cardiac output, cardiac index, stroke volume, and stroke volume variation.

Gastric pH variation during different positioning conditions. Adverse events including hypotension, accidental ventilator disconnection, respiratory discomfort, or significant gastroesophageal reflux.

Pre-intervention Procedures

Before starting the protocol, a standardized preparation process will be performed to ensure clinical stability, measurement accuracy, and consistency across all participants. The following procedures will be applied:

Closed-system suctioning to minimize secretion accumulation and avoid measurement artifacts.

Adjustment of ventilator settings in Volume-Controlled Ventilation (VCV) mode, using a square wave flow pattern. Respiratory rate (RR), inspiratory-to-expiratory ratio (I:E), fraction of inspired oxygen (FiO₂), and tidal volume (Vt) will be maintained according to baseline parameters.

Positive End-Expiratory Pressure (PEEP) will be maintained at the baseline value plus 2 cmH₂O during lateralization phases, to compensate for potential changes in thoracic mechanics and prevent derecruitment.

Placement of the interface pressure sensor (ForeSite PT, XSENSOR) will be performed by two trained professionals to ensure correct positioning, alignment, and reduction of artifacts.

Bed surface and sensor positioning will be inspected to eliminate any folds, misalignments, or sensor displacements that could interfere with pressure measurements.

The esophageal pH monitoring system will be zeroed and calibrated before each change in the head-of-bed elevation, ensuring accurate pH recording.

Proton pump inhibitor (PPI) administration will be rescheduled prior to the protocol, and the enteral feeding tube must be confirmed in a post-pyloric position, reducing the risk of reflux and interference with pH measurements.

Inclusion Criteria

• Adult and elderly patients, aged 18 years or older;
• Patients under controlled or assisted mechanical ventilation, not yet eligible for weaning.

Exclusion Criteria

• Requirement of norepinephrine > 0.3 mcg/kg/min or mean arterial pressure < 60 mmHg, despite the use of vasopressor agents;
• Cardiac arrhythmias or bleeding leading to hemodynamic instability;
• Neurological diseases or symptoms;
• Spinal cord injury, such as paraplegia;
• Cardiac pacemaker dependence;
• Contraindications to hypercapnia, such as intracranial hypertension or acute coronary syndrome;
• Air leakage from chest drains, presence of pneumothorax or undrained subcutaneous emphysema;
• Presence of pre-existing pressure injuries in bony prominences (sacral, occipital, scapular, or calcaneal) at admission;
• Medical refusal to include the patient in the study.