Respiratory InsufficiencyNCT03309423
Is Venous to Arterial Conversion (v-TAC) of Blood Gas Reliable in Critical Ill Patients in the ICU?
An observational study of Respiratory Insufficiency and Metabolic Disease, run by Aalborg University at 1 site in Denmark.
Trial summary
Objective: Arterial blood gas (ABG) is essential in the clinical assessment of potential acutely ill patients venous to arterial conversion (v-TAC), a mathematical method, has recently been developed to convert peripheral venous blood gas (VBG) values to arterialized VBG (aVBG) values. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Respiratory Insufficiency, Metabolic Disease, Acidosis
- What is being tested?
- venous to arterial conversion (v-TAC)
- How many people
- 50 participants
- Where
- 1 siteDenmark
- Study dates
- 9 Oct 2017to 30 Mar 2018
- Phase
- Observational
- Are there results?
- None posted in the registry
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 Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: All patients admitted to the ICU with acid-base and oxygenation parameters outside the normal reference values.
Who may be able to join
- All patients admitted to the intensive care with the following:
- Arterial catheter for other purpose.
- Peripheral venous catheter or central venous catheter for other purpose.
Who cannot join
- Normal pH in arterial blood gas.
Trial locations and contacts
1 site in 1 country.
Denmark1 site, 1 recruiting
- Recruiting
Faculty of Medicine, Doctoral School, Ph.d. study
Aalborg, North Denmark, 9000
Christina Elmer, Secretary, doctoral.school@adm.aau.dk
Mads Lumholdt, Cand. Med.
About this study
Official title: Utility of Mathematically Converted Venous to Arterial Blood Gas for Clinical Monitoring
Objective: Arterial blood gas (ABG) is essential in the clinical assessment of potential acutely ill patients venous to arterial conversion (v-TAC), a mathematical method, has recently been developed to convert peripheral venous blood gas (VBG) values to arterialized VBG (aVBG) values. The aim of this study is to test the reliability of aVBG compared to ABG in an intensive care unit (ICU) setting.
Method: Consecutive patients admitted to the ICU with pH values <7,35 or >7,45 are included in this study. Paired ABG and aVBG samples are drawn from patients via arterial catheter, central venous catheter and/or peripheral venous catheter and compared.
Read the detailed description
Arterial blood gas (ABG) analysis is essential in assessment of respiratory and metabolic status in acutely ill patients. In comparison to peripheral venous blood (PVG) sampling, the ABG sampling procedure is more painful for the patient and technically more challenging for the clinician to perform. Other drawbacks of ABG sampling include adverse events such as subcutaneous hematoma, arterial thrombosis or embolization, and pseudoaneurysms.
Peripheral venous blood gas (VBG) sampling has been suggested as an alternative to the ABG procedure. This procedure causes less patient discomfort and the sample can be analysed in combination with other venous blood tests. Studies have revealed that pH and bicarbonate have good correlation, whereas venous and arterial blood gasses (pO2 and pCO2) show low agreement.
However, a new method has been developed to calculate ABG values mathematically from peripheral venous blood by use of venous to arterial conversion (v-TAC) software (Obimedical, Denmark), supplemented with oxygen saturation measured by pulse oximetry. The principle of the method is a mathematical transformation of VBG values to arterialized values (aVBG) by simulating the transport of blood back through the tissue. Initial testing of the method in an emergency department setting showed acceptable clinical congruence between arterial and mathematically arterialized pH and pCO2 with a small difference (+/- SD) on 0.001 +/- 0.024 and 0.00 0.46 kPa, respectively. However, inaccurate values of pO2 were seen when oxygen saturation measured by pulse oximetry was above 96%, due to the flat shape of the oxygen dissociation curve (ODC).
Although most patients in the ICU have arterial catheters therefrom ABG can be drawn, applying arterial catheter is difficult or even impossible in some patients. In relation to step-down some patients get arterial catheters removed and in the event of deterioration in patients acid-base or respiratory disease aVBG could prove useful as a minimally invasive tool to assess patients status.
The aim of this study is to investigate if v-TAC is reliable and safe to use in patients with critically respiratory or metabolic disease admitted to the ICU.
- Conditions
- Respiratory Insufficiency, Metabolic Disease, Acidosis, Alkalosis, Sepsis, Abdomen, Acute
- Being tested
- venous to arterial conversion (v-TAC)
- Keywords
- Blood gas analysis, Critical care, venus to arterial conversion
- Medical subject headings
- Respiratory Insufficiency, Metabolic Diseases, Acidosis, Alkalosis, Sepsis, Abdomen, Acute
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
venous to arterial conversion (v-TAC)Diagnostic test
Venous to arterial conversion (v-TAC) is a software (Obimedical, Denmark), which can convert venous blood gas values to arterial blood gas values. The principle of the method is a mathematical transformation of VBG values to arterialized values (aVBG) by simulating the transport of blood back through the tissue. To facilitate this simulation the following physiologically relevant assumptions were made: 1) The peripheral extremity was well perfused; 2) change in base excess across the tissue sampling site was approximately zero; 3) the respiratory quotient (rate of CO2 production and O2 utilisation over capillaries) could not vary outside the range 0.7 and 1.0, and 4) the haemoglobin concentration was constant from artery to vein.
| Study group | Role | What they receive |
|---|---|---|
| Respiratory disease | Patients with acute respiratory insufficiency admitted to the ICU and with pH <7,35 or >7,45 Receives: Diagnostic Test: venous to arterial conversion (v-TAC) | |
| Metabolic disease | Patients with acute metabolic disease admitted to the ICU and with pH <7,35 or >7,45 Receives: Diagnostic Test: venous to arterial conversion (v-TAC) | |
| Sepsis | Patients with acute sepsis admitted to the ICU and with pH <7,35 or >7,45 Receives: Diagnostic Test: venous to arterial conversion (v-TAC) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Lin's Concordance correlation coefficient (CCC)
Comparison of pH between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Lin's Concordance correlation coefficient (CCC)
Comparison of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Lin's Concordance correlation coefficient (CCC)
Comparison of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Lin's Concordance correlation coefficient (CCC)
Comparison of pH between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Lin's Concordance correlation coefficient (CCC)
Comparison of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Lin's Concordance correlation coefficient (CCC)
Comparison of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pH between ABG and aVBG (from peripheral venous catheter)
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter).
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter).
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pH between ABG and aVBG (from central venous catheter).
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter).
Measured: 1. january 2018
Bland and Altman's plot
Mean difference and 95% limits-of-agreement of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter).
Measured: 1. january 2018
Secondary outcomes (6)
Number of patients with sepsis group.
Number and percentage of patients in 'sepsis' group.
Measured: 1. january 2018
Number of patient with metabolic disease
Number and percentage of patients in 'metabolic disease' group.
Measured: 1. january 2018
Number of patient with acute respiratory insufficiency
Number and percentage of patients in 'respiratory disease group' group.
Measured: 1. january 2018
Mean number of days until pH neutrality in sepsis group
Mean number of days until patients ABG pH was within the range 7.35-7.45 in 'sepsis' group.
Measured: 1. january 2018
Mean number of days until pH neutrality in patients with metabolic disease.
Mean number of days until patients ABG pH was within the range 7.35-7.45 in 'metabolic disease' group.
Measured: 1. january 2018
Mean number of days until pH neutrality in patients with respiratory disease.
Mean number of days until patients ABG pH was within the range 7.35-7.45 in 'respiratory disease' group.
Measured: 1. january 2018
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Oct 2017
- Study start9 Oct 2017
- Primary completion30 Jan 2018 (estimated)
- Study completion30 Mar 2018 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Respiratory InsufficiencyStudies of the same condition, open and under way.
- 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
- Case only
- Time perspective
- Prospective
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Aalborg University
- Sponsor type
- University, hospital or other
- Collaborators
- Regionshospital Nordjylland
- Responsible party
- Principal investigator, Mads Lumholdt, Aalborg University
- Investigators
- Peter Leutscher, Study director, Professor, Center for Clinical Research
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03309423
- Sponsor's protocol ID
- v-TAC-ICU
- Status last verified
- Oct 2017
- First submitted
- 4 Oct 2017
- Last updated
- 13 Oct 2017
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: IPD will be stored in safe government controlled data drives and paper data will be stored in a secure office. Doors to this office will be closed when investigators are not present. Sensitive IPD will not be shared with external researchers.
Study at a glance
From the registry record, last updated by the sponsor on 13 Oct 2017. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Utility of Mathematically Converted Venous to Arterial Blood Gas for Clinical Monitoring
- ClinicalTrials.gov ID
- NCT03309423
- Acronym / sponsor ID
- v-TAC-ICU
- Conditions
- Respiratory Insufficiency, Metabolic Disease, Acidosis, Alkalosis, Sepsis, Abdomen, Acute
- Keywords
- Blood gas analysis, Critical care, venus to arterial conversion
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Aalborg UniversityUniversity, hospital or other
- Collaborators
- Regionshospital Nordjylland
- Study start
- 9 Oct 2017 (actual)
- Primary completion
- 30 Jan 2018 (estimated)
- Study completion
- 30 Mar 2018 (estimated)
- First posted
- 13 Oct 2017 (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.
Objective: Arterial blood gas (ABG) is essential in the clinical assessment of potential acutely ill patients venous to arterial conversion (v-TAC), a mathematical method, has recently been developed to convert peripheral venous blood gas (VBG) values to arterialized VBG (aVBG) values. The aim of this study is to test the reliability of aVBG compared to ABG in an intensive care unit (ICU) setting.
Method: Consecutive patients admitted to the ICU with pH values <7,35 or >7,45 are included in this study. Paired ABG and aVBG samples are drawn from patients via arterial catheter, central venous catheter and/or peripheral venous catheter and compared.
Detailed description
Arterial blood gas (ABG) analysis is essential in assessment of respiratory and metabolic status in acutely ill patients. In comparison to peripheral venous blood (PVG) sampling, the ABG sampling procedure is more painful for the patient and technically more challenging for the clinician to perform. Other drawbacks of ABG sampling include adverse events such as subcutaneous hematoma, arterial thrombosis or embolization, and pseudoaneurysms.
Peripheral venous blood gas (VBG) sampling has been suggested as an alternative to the ABG procedure. This procedure causes less patient discomfort and the sample can be analysed in combination with other venous blood tests. Studies have revealed that pH and bicarbonate have good correlation, whereas venous and arterial blood gasses (pO2 and pCO2) show low agreement.
However, a new method has been developed to calculate ABG values mathematically from peripheral venous blood by use of venous to arterial conversion (v-TAC) software (Obimedical, Denmark), supplemented with oxygen saturation measured by pulse oximetry. The principle of the method is a mathematical transformation of VBG values to arterialized values (aVBG) by simulating the transport of blood back through the tissue. Initial testing of the method in an emergency department setting showed acceptable clinical congruence between arterial and mathematically arterialized pH and pCO2 with a small difference (+/- SD) on 0.001 +/- 0.024 and 0.00 0.46 kPa, respectively. However, inaccurate values of pO2 were seen when oxygen saturation measured by pulse oximetry was above 96%, due to the flat shape of the oxygen dissociation curve (ODC).
Although most patients in the ICU have arterial catheters therefrom ABG can be drawn, applying arterial catheter is difficult or even impossible in some patients. In relation to step-down some patients get arterial catheters removed and in the event of deterioration in patients acid-base or respiratory disease aVBG could prove useful as a minimally invasive tool to assess patients status.
The aim of this study is to investigate if v-TAC is reliable and safe to use in patients with critically respiratory or metabolic disease admitted to the ICU.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Respiratory disease | – | Diagnostic Test: venous to arterial conversion (v-TAC)Patients with acute respiratory insufficiency admitted to the ICU and with pH <7,35 or >7,45 |
| Metabolic disease | – | Diagnostic Test: venous to arterial conversion (v-TAC)Patients with acute metabolic disease admitted to the ICU and with pH <7,35 or >7,45 |
| Sepsis | – | Diagnostic Test: venous to arterial conversion (v-TAC)Patients with acute sepsis admitted to the ICU and with pH <7,35 or >7,45 |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- All patients admitted to the ICU with acid-base and oxygenation parameters outside the normal reference values.
Key inclusion criteria (3 listed)
- All patients admitted to the intensive care with the following:
- Arterial catheter for other purpose.
- Peripheral venous catheter or central venous catheter for other purpose.
Key exclusion criteria (1 listed)
- Normal pH in arterial blood gas.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| venous to arterial conversion (v-TAC)Venous to arterial conversion (v-TAC) is a software (Obimedical, Denmark), which can convert venous blood gas values to arterial blood gas values. The principle of the method is a mathematical transformation of VBG values to arterialized values (aVBG) by simulating the transport of blood back through the tissue. To facilitate this simulation the following physiologically relevant assumptions were made: 1) The peripheral extremity was well perfused; 2) change in base excess across the tissue sampling site was approximately zero; 3) the respiratory quotient (rate of CO2 production and O2 utilisation over capillaries) could not vary outside the range 0.7 and 1.0, and 4) the haemoglobin concentration was constant from artery to vein. | Diagnostic test | Metabolic disease, Respiratory disease, Sepsis |
Primary outcome
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pH between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter). The closer CCC is to 1 the better correlation.
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pH between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Lin's Concordance correlation coefficient (CCC)
Time frame: 1. january 2018
Comparison of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter). The closer CCC is to 1 the better correlation.
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pH between ABG and aVBG (from peripheral venous catheter)
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter).
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from peripheral venous catheter).
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pH between ABG and aVBG (from central venous catheter).
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pCO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter).
Bland and Altman's plot
Time frame: 1. january 2018
Mean difference and 95% limits-of-agreement of pO2 (Unit of Measurement: kilopascal) between ABG and aVBG (from central venous catheter).
6 secondary outcomes
Number of patients with sepsis group.
Time frame: 1. january 2018
Number of patient with metabolic disease
Time frame: 1. january 2018
Number of patient with acute respiratory insufficiency
Time frame: 1. january 2018
Mean number of days until pH neutrality in sepsis group
Time frame: 1. january 2018
Mean number of days until pH neutrality in patients with metabolic disease.
Time frame: 1. january 2018
Mean number of days until pH neutrality in patients with respiratory disease.
Time frame: 1. january 2018
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Oct 2017.
- Individual participant dataSharing planned: No. IPD will be stored in safe government controlled data drives and paper data will be stored in a secure office. Doors to this office will be closed when investigators are not present. Sensitive IPD will not be shared with external researchers.
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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. This study is not recruiting at the moment.
Peter Leutscher study director
Professor, Center for Clinical Research
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Respiratory Insufficiency and Metabolic Disease, run by Aalborg University at 1 site in Denmark.
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 3 inclusion and 1 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: status not confirmed, as of the sponsor's last update on 13 Oct 2017. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Mads Lumholdt (+45 51914156, m.lumholdt@rn.dk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Lin's Concordance correlation coefficient (CCC) (time frame: 1. january 2018). The study lists 12 primary outcomes in all. 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 13 Oct 2017.