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Correlation of EtCO₂- and P(A-a)O₂-Based Dead Space Calculations in Mechanically Ventilated ICU Patients

NCT06947486 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 41

Last updated 2025-04-27

No results posted yet for this study

Summary

This study aims to evaluate two different methods for calculating physiological dead space in adult patients undergoing invasive mechanical ventilation in the intensive care unit (ICU). Physiological dead space refers to the portion of air that is ventilated but does not participate in gas exchange due to impaired perfusion or ventilation-perfusion mismatch.

Traditionally, dead space is calculated using the end-tidal carbon dioxide (EtCO₂) method, which estimates the difference between arterial and exhaled CO₂ values. However, this method may be influenced by circulatory failure or abnormal CO₂ distribution. An alternative method using the alveolar-arterial oxygen gradient \[P(A-a)O₂\] has been proposed, as it may provide a more stable measurement under critical conditions by relying on oxygenation efficiency rather than CO₂ elimination.

In this prospective observational study, patients receiving mechanical ventilation in a tertiary ICU will be monitored. Physiological dead space will be calculated using both the EtCO₂-based method and the P(A-a)O₂-based method. Various respiratory and clinical parameters, including arterial blood gases, ventilator settings, and severity scores, will be recorded. The correlation between the two methods will be assessed, and their relationship with ICU mortality will be analyzed.

The results of this study may help determine whether the P(A-a)O₂ method can be used as a reliable alternative for estimating dead space in ICU patients and whether it has prognostic value in predicting patient outcomes.

Conditions

  • Physiological Dead Space
  • Ventilation-Perfusion Mismatch
  • Mechanical Ventilation
  • Enghoff Correction

Sponsors & Collaborators

  • Karadeniz Technical University

    lead OTHER

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2025-01-05
Primary Completion
2025-04-10
Completion
2025-04-18

Countries

  • Turkey (Türkiye)

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT06947486 on ClinicalTrials.gov