This study aims to investigate skin barrier function in intensive care unit (ICU) patients using biosensor-based measurements. Biophysical parameters including transepidermal water loss (TEWL), skin pH, stratum corneum hydration, local skin temperature, and sebum will be assessed in anatomical regions at risk for pressure injuries. The study will examine temporal changes in these parameters, their interrelationships, and their association with pressure injury development.

Pressure injuries (PIs) remain a major complication in intensive care units (ICUs), associated with increased morbidity, mortality, and healthcare costs. Early detection and prevention are critical; however, current assessment methods rely largely on subjective clinical evaluation and risk scales, which may lack sensitivity in detecting subclinical skin barrier impairment.

Recent advances in biosensor technology enable objective, non-invasive assessment of skin barrier function through biophysical parameters such as transepidermal water loss (TEWL), skin pH, stratum corneum hydration, local temperature, and sebum levels. These parameters reflect epidermal integrity and may provide early indicators of pressure-induced tissue damage before visible clinical signs emerge.

The SKIN-BAR study is designed as a prospective, longitudinal cohort study conducted in ICU patients. The primary objective is to evaluate skin barrier function in pressure injury-prone anatomical regions and to identify factors influencing these parameters. Specifically, the study aims to:

1. assess temporal changes in biophysical skin parameters,
2. examine relationships between these parameters,
3. compare measurements between pressure injury-developing and non-developing patients, and
4. identify clinical and demographic factors associated with impaired skin barrier function.

Data will be collected using validated, non-invasive biosensor devices. Measurements will be performed at multiple time points (including early ICU admission and follow-up intervals) and across multiple anatomical sites, including the sacrum, trochanters, scapulae, lateral legs, and posterior neck. Control measurements from adjacent intact skin will also be obtained.

A comprehensive dataset including clinical, demographic, and physiological variables will be analyzed to determine predictors of pressure injury development and to better understand the pathophysiological mechanisms underlying skin barrier disruption in critically ill patients.

This study is expected to contribute to the development of objective, evidence-based approaches for early detection and prevention of pressure injuries in ICU settings and to support the integration of biosensor technologies into clinical care protocols.

Inclusion Criteria:

• Adults aged >18 years
• Admission to the intensive care unit
• Initial skin assessment completed within the first 4 hours after ICU admission
• Hemodynamically stable enough to undergo follow-up and repeated skin measurements
• Intact skin integrity at ICU admission
• Willingness to participate in the study, with informed consent provided by the participant or legally authorized representative

Exclusion Criteria:

• Inability to tolerate position changes
• Post-cardiopulmonary resuscitation care period at enrollment
• Cardiac arrest or cardiopulmonary resuscitation during follow-up
• Severe edema or subcutaneous fluid accumulation
• Presence of skin lesions before ICU admission
• Systemic dermatologic disease directly affecting skin barrier function

Adult critically ill patients admitted to the intensive care unit (ICU) and at risk for pressure injury development will be enrolled. Participants will undergo longitudinal, non-invasive biosensor-based assessments of skin barrier function in pressure injury-prone anatomical regions throughout their ICU stay. The population will include both patients who develop pressure injuries and those who do not.

Individual participant data (IPD) sharing is currently undecided. Due to the sensitive nature of clinical data collected in an intensive care unit setting and institutional data protection policies, data sharing will be considered after study completion. Any potential data sharing will involve fully de-identified datasets and will require appropriate ethical approvals and data use agreements.