Critical IllnessNCT07799727
Central Venous vs Arterial Blood Gas and CO2 Gap in Critically Ill Patients With and Without Diabetes
An observational study of Critical Illness and Diabetes Mellitus, run by Assiut University.
Trial summary
Frequent monitoring of acid-base status, ventilation, and tissue oxygenation is essential for managing critically ill patients in the intensive care unit (ICU). While arterial blood gas (ABG) analysis is considered the standard method for these evaluations, maintaining arterial catheters carries risks of… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Critical Illness, Diabetes Mellitus, Acid-Base Imbalance
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- Oct 2026to Nov 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Adult, Older adult
Study population: Adult critically ill patients (both diabetic and non-diabetic) admitted to the Critical Care Unit of the Internal Medicine Department at Assiut University Hospital who have standard clinical indications for indwelling central venous catheters and arterial lines.
Who may be able to join
- Adult patients aged 18 years and older
- Critically ill patients admitted to the intensive care unit (ICU)
- Patients with indwelling central venous catheter and arterial line placed for routine clinical management
- Written informed consent obtained from the patient or legal next of kin
Who cannot join
- Known severe peripheral vascular occlusive disease affecting line placement
- Use of a pulmonary artery catheter (mixed venous blood line) instead of a standard central venous catheter positioned at the superior/inferior vena cava junction
- Refusal of the patient or legal representative to participate in the study
- Patients younger than 18 years of age
About this study
Official title: Correlation Between Central Venous and Arterial Blood Gas Parameters Including CO2 Gap in Diabetic and Non-Diabetic Critically Ill Patients
Frequent monitoring of acid-base status, ventilation, and tissue oxygenation is essential for managing critically ill patients in the intensive care unit (ICU). While arterial blood gas (ABG) analysis is considered the standard method for these evaluations, maintaining arterial catheters carries risks of complications, such as thrombosis, hematoma, and infection. Central venous blood gas (CVBG) analysis offers a safer alternative because central venous catheters are already routinely placed for patient care. Additionally, the venous-to-arterial carbon dioxide difference (CO2 gap) serves as an indicator of systemic blood flow and tissue perfusion.
However, patients with diabetes mellitus often present with underlying microvascular alterations, endothelial changes, and metabolic variations that might alter tissue perfusion and peripheral gas exchange. This study aims to assess the correlation and agreement between central venous and arterial blood gas parameters, as well as evaluate the diagnostic accuracy of the CO2 gap, in diabetic versus non-diabetic critically ill patients.
A total of 100 adult ICU patients (50 diabetic and 50 non-diabetic) with pre-existing central venous and arterial lines will be enrolled. Paired blood samples will be drawn simultaneously to compare blood gas values and calculate the CO2 gap without altering standard clinical treatment.
- Keywords
- Central Venous Blood Gas, Arterial Blood Gas, CO2 Gap, Venous-to-arterial PCO2 Difference, Intensive Care Unit
- Medical subject headings
- Critical Illness, Diabetes Mellitus, Acid-Base Imbalance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Diabetic Critically Ill Patients | Critically ill adult patients admitted to the intensive care unit who have a confirmed diagnosis of Diabetes Mellitus. All participants undergo simultaneous paired arterial and central venous blood gas sampling to evaluate agreement and CO2 gap dynamics. | |
| Non-Diabetic Critically Ill Patients | Critically ill adult patients admitted to the intensive care unit without a history or diagnosis of Diabetes Mellitus. All participants undergo simultaneous paired arterial and central venous blood gas sampling to evaluate agreement and CO2 gap dynamics. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Venous-to-Arterial Carbon Dioxide Tension Difference (Delta PCO2)
Delta PCO2 (CO2 gap) is calculated as central venous PCO2 minus arterial PCO2 (PvCO2 - PaCO2) measured in mmHg. Paired arterial and central venous blood gas samples are collected simultaneously and analyzed within 10 minutes.
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Sep 2026
- Study startOct 2026 (estimated)
- Primary completionOct 2027 (estimated)
- Study completionNov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Critical IllnessStudies of the same condition, open and under way.
- More trials run by Assiut UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assiut University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mahmoud Mohamed Ali Abdelhafez, Assiut University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07799727
- Sponsor's protocol ID
- CVBG vs ABG in ICU Diabetics
- Status last verified
- Aug 2026
- First submitted
- 30 Aug 2026
- Last updated
- 2 Sep 2026
- Results posted
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Correlation Between Central Venous and Arterial Blood Gas Parameters Including CO2 Gap in Diabetic and Non-Diabetic Critically Ill Patients
- ClinicalTrials.gov ID
- NCT07799727
- Acronym / sponsor ID
- CVBG vs ABG in ICU Diabetics
- Keywords
- Central Venous Blood Gas, Arterial Blood Gas, CO2 Gap, Venous-to-arterial PCO2 Difference, Intensive Care Unit
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Assiut UniversityUniversity, hospital or other
- Study start
- Oct 2026 (estimated)
- Primary completion
- Oct 2027 (estimated)
- Study completion
- Nov 2027 (estimated)
- First posted
- 2 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Frequent monitoring of acid-base status, ventilation, and tissue oxygenation is essential for managing critically ill patients in the intensive care unit (ICU). While arterial blood gas (ABG) analysis is considered the standard method for these evaluations, maintaining arterial catheters carries risks of complications, such as thrombosis, hematoma, and infection. Central venous blood gas (CVBG) analysis offers a safer alternative because central venous catheters are already routinely placed for patient care. Additionally, the venous-to-arterial carbon dioxide difference (CO2 gap) serves as an indicator of systemic blood flow and tissue perfusion.
However, patients with diabetes mellitus often present with underlying microvascular alterations, endothelial changes, and metabolic variations that might alter tissue perfusion and peripheral gas exchange. This study aims to assess the correlation and agreement between central venous and arterial blood gas parameters, as well as evaluate the diagnostic accuracy of the CO2 gap, in diabetic versus non-diabetic critically ill patients.
A total of 100 adult ICU patients (50 diabetic and 50 non-diabetic) with pre-existing central venous and arterial lines will be enrolled. Paired blood samples will be drawn simultaneously to compare blood gas values and calculate the CO2 gap without altering standard clinical treatment.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Diabetic Critically Ill Patients | – | –Critically ill adult patients admitted to the intensive care unit who have a confirmed diagnosis of Diabetes Mellitus. All participants undergo simultaneous paired arterial and central venous blood gas sampling to evaluate agreement and CO2 gap dynamics. |
| Non-Diabetic Critically Ill Patients | – | –Critically ill adult patients admitted to the intensive care unit without a history or diagnosis of Diabetes Mellitus. All participants undergo simultaneous paired arterial and central venous blood gas sampling to evaluate agreement and CO2 gap dynamics. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Adult critically ill patients (both diabetic and non-diabetic) admitted to the Critical Care Unit of the Internal Medicine Department at Assiut University Hospital who have standard clinical indications for indwelling central venous catheters and arterial lines.
Key inclusion criteria (4 listed)
- Adult patients aged 18 years and older
- Critically ill patients admitted to the intensive care unit (ICU)
- Patients with indwelling central venous catheter and arterial line placed for routine clinical management
- Written informed consent obtained from the patient or legal next of kin
Key exclusion criteria (4 listed)
- Known severe peripheral vascular occlusive disease affecting line placement
- Use of a pulmonary artery catheter (mixed venous blood line) instead of a standard central venous catheter positioned at the superior/inferior vena cava junction
- Refusal of the patient or legal representative to participate in the study
- Patients younger than 18 years of age
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Venous-to-Arterial Carbon Dioxide Tension Difference (Delta PCO2)
Time frame: Baseline
Delta PCO2 (CO2 gap) is calculated as central venous PCO2 minus arterial PCO2 (PvCO2 - PaCO2) measured in mmHg. Paired arterial and central venous blood gas samples are collected simultaneously and analyzed within 10 minutes.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Sep 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of Critical Illness and Diabetes Mellitus, run by Assiut University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 2 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Venous-to-Arterial Carbon Dioxide Tension Difference (Delta PCO2) (time frame: Baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Sep 2026.