The Value of Partial Arterial Carbon Dioxide Pressure - End-Tidal Carbon Dioxide Gradient Courses in Predicting Acute Renal Injury in Critically Ill Patients on Mechanical Ventilation: A Novel Hemodynamic Marker?

Malatya Egitim Ve Arastirma Hastanesi155 enrolled

Overview

End-tidal carbon dioxide (EtCO₂) refers to the level of carbon dioxide in the air exhaled during expiration and is measured using capnography. EtCO₂ is an important monitoring parameter in the management of critically ill patients on mechanical ventilation, providing indirect information about the patient's cardiac output, pulmonary perfusion-ventilation (V/Q) status, and metabolic activity. The Pa-EtCO₂ gradient, the difference between EtCO₂ and arterial CO₂ partial pressure (PaCO₂), changes significantly, especially in cases of hemodynamic deterioration, microcirculatory failure, and increased dead space. Therefore, the gradient is considered a potential indicator of perfusion in critically ill patients. In critically ill patients on mechanical ventilation, the usability of changes (courses) of the Pa-EtCO₂ gradient over time is being evaluated not only as an indicator of ventilation but also as a dynamic and indirect predictor of hemodynamic status and renal perfusion. Therefore, it should be investigated whether the Pa-EtCO2 gradient is a suitable parameter for early detection of AKI (acute kidney injury) development in patients with renal perfusion impairment.

Study Type

OBSERVATIONAL

Enrollment

155

Conditions

Acute Kidney Injury Ventilated Patient in Intensive Care

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients over 18 years of age * patients under mechanical ventilation * initiation of EtCO₂ monitoring within the first hour of admission to the ICU * patients monitored in the ICU for at least 24 hours * having undergone arterial blood gas analysis (for PaCO₂ measurement) within the first 24 hours. Exclusion Criteria: * Patients under 18 years of age * intensive care unit monitoring shorter than 24 hours * missing or inaccessible clinical data * chronic renal failure * acute renal failure present at admission to intensive care unit * advanced pulmonary diseases affecting EtCO₂ measurement (e.g., severe obstruction, giant bulla, advanced emphysema) * patients in whom PaCO₂ measurement cannot be performed

Outcomes

Primary Outcomes

Change From Baseline in PaCO₂-EtCO₂ Gradient at 6, 12, and 24 Hours After ICU Admission

The PaCO₂-EtCO₂ gradient will be calculated as arterial carbon dioxide pressure minus end-tidal carbon dioxide pressure at baseline and at 6, 12, and 24 hours after ICU admission. Change from baseline will be reported for each follow-up time point in mmHg.

Time frame: Baseline, 6 hours, 12 hours, and 24 hours after ICU admission