Arterial blood gas analysis is commonly used in pediatric intensive care units (PICUs) to assess oxygen and carbon dioxide levels in critically ill children. However, arterial blood sampling is invasive, can be painful, and may need to be repeated frequently. Transcutaneous monitoring provides a noninvasive method to continuously measure oxygen (pO₂) and carbon dioxide (pCO₂) levels through the skin, but its accuracy in critically ill pediatric patients requires further evaluation.

The purpose of this observational study is to compare transcutaneous pO₂ and pCO₂ measurements with arterial blood gas values in pediatric intensive care unit patients. By analyzing paired measurements obtained simultaneously during routine clinical care, this study aims to evaluate the agreement between transcutaneous and arterial measurements, with a particular focus on whether transcutaneous pO₂ can serve as a reliable alternative to arterial sampling.

The results of this study may help clarify the role of transcutaneous monitoring in pediatric intensive care and may contribute to reducing the need for invasive blood sampling in selected patients.

Detailed Description

Arterial blood gas (ABG) analysis is the gold standard for assessing oxygenation and ventilation in critically ill children admitted to the pediatric intensive care unit (PICU). Despite its clinical value, ABG sampling is invasive, may cause discomfort, and often requires repeated blood draws. Transcutaneous monitoring offers a noninvasive, continuous method for estimating partial pressures of oxygen (pO₂) and carbon dioxide (pCO₂) through the skin. However, the accuracy and clinical reliability of transcutaneous measurements in critically ill pediatric patients remain variable and require further evaluation.

This observational cohort study aims to assess the agreement between transcutaneous pO₂ (Tc pO₂) and pCO₂ (Tc pCO₂) measurements and corresponding arterial blood gas values (PaO₂ and PaCO₂) in pediatric patients admitted to the PICU. Eligible patients are those who undergo arterial blood gas sampling and concurrent transcutaneous monitoring as part of routine clinical care. Paired measurements will be obtained simultaneously to minimize temporal variability and ensure comparability.

The primary outcome of the study is the agreement between Tc pO₂ and PaO₂ measurements. Secondary analyses will evaluate the agreement between Tc pCO₂ and PaCO₂ values. Agreement will be assessed using appropriate statistical methods, including correlation analysis and Bland-Altman analysis, to determine bias and limits of agreement between measurement techniques.

By evaluating the performance of transcutaneous monitoring in a real-world PICU setting, this study seeks to determine whether Tc pO₂ can be considered a reliable alternative to arterial oxygen measurements in selected pediatric patients. The findings may support the integration of noninvasive monitoring strategies into clinical practice and potentially reduce the frequency of invasive arterial blood sampling in pediatric intensive care.

Eligibility Criteria

Inclusion Criteria:

• Age between 1 month and 18 years
• Admission to the Pediatric Intensive Care Unit (PICU)
• Presence of an arterial catheter allowing arterial blood gas (ABG) sampling
• Simultaneous or paired transcutaneous pCO₂ and pO₂ monitoring available
• Hemodynamically stable at the time of measurement

Exclusion Criteria:

• Severe skin disease, burns, or local skin infection at the transcutaneous sensor site
• Severe peripheral perfusion impairment (e.g., refractory shock or high-dose vasopressor support)
• Congenital or acquired conditions interfering with accurate transcutaneous measurements
• Technical failure or inability to obtain reliable transcutaneous readings
• Missing or incomplete paired ABG-transcutaneous measurement data

This study will include pediatric patients aged 1 month to 18 years admitted to the Pediatric Intensive Care Unit (PICU) who undergo arterial blood gas analysis and concurrent transcutaneous pCO₂ and pO₂ monitoring as part of routine clinical care. Patients with an indwelling arterial catheter and adequate peripheral perfusion allowing reliable transcutaneous measurements will be eligible. The study population represents critically ill children requiring close respiratory and hemodynamic monitoring in the PICU setting.