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?

NCT07654010 | Completed

• 1 other identifier: MEAH-AKI-ICU-2026-01
• Study Type: observational
• Target: 155
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Acute Kidney Injury; Ventilated Patient in Intensive Care

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline, 6 hours, 12 hours, and 24 hours after ICU admission

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

patients being monitored with mechanical ventilators in intensive care

You may qualify if:

• 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.

You may not qualify if:

• 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

Sponsors & Collaborators

• Malatya Egitim Ve Arastirma Hastanesi: lead

Study Sites (1)

Malatya Training and Research Hospital

Malatya, Osmaniye, +90(505)620-3888, Turkey (Türkiye)

Location

Related Publications (3)

• Defilippis V, D'Antini D, Cinnella G, Dambrosio M, Schiraldi F, Procacci V. End-tidal arterial CO2 partial pressure gradient in patients with severe hypercapnia undergoing noninvasive ventilation. Open Access Emerg Med. 2013 Jun 19;5:1-7. doi: 10.2147/OAEM.S43070. eCollection 2013.

  PMID: 27147867 RESULT

• Belenkiy SM, Berry JS, Batchinsky AI, Kendrick C, Necsoiu C, Jordan BS, Salinas J, Cancio LC. The noninvasive carbon dioxide gradient (NICO2G) during hemorrhagic shock. Shock. 2014 Jul;42(1):38-43. doi: 10.1097/SHK.0000000000000177.

  PMID: 24667626 RESULT

• Inan G, Kara Cetsmall i, Ukrainiannbsmall i, Ukrainianlek PH, Gonullu H. Comparison of End-Tidal Carbon Dioxide (ETCO2) Gradient and Vena Cava Collapsibility Index (VCCI) in Response to Intravenous Fluid Therapy in Patients with Moderate and Severe Dehydration and Acute Gastroenteritis. Prehosp Disaster Med. 2022 Aug;37(4):474-479. doi: 10.1017/S1049023X22000838. Epub 2022 May 25.

  PMID: 35611835 RESULT

MeSH Terms

Conditions

Acute Kidney Injury

Condition Hierarchy (Ancestors)

Renal Insufficiency; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Target Duration: 30 Days
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: April 9, 2026
• First Posted: June 17, 2026
• Study Start: March 15, 2026
• Primary Completion: May 15, 2026
• Study Completion: June 5, 2026
• Last Updated: June 17, 2026

Record last verified: 2026-01

Locations

TU (1)