Video-Assisted Thoracoscopic SurgeryNCT06835894
Trending Ability of End-Tidal Capnography to Reflect Arterial Carbon Dioxide Changes in One-Lung Ventilation
An observational study of Video-Assisted Thoracoscopic Surgery and One-Lung Ventilation, run by Koç University.
Trial summary
In this study, we want to find out if measuring carbon dioxide from a patient's breath (end-tidal CO₂ or ETCO₂) can reliably reflect changes in blood carbon dioxide levels (arterial CO₂ or PaCO₂) during lung surgery. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Video-Assisted Thoracoscopic Surgery, One-Lung Ventilation, Capnography
- How many people
- 115 participants
- Where
- No sites listed yet
- Study dates
- 1 Apr 2025to 10 Jul 2025
- 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: Participants will be drawn from the adult patient population (≥18 years) scheduled for thoracoscopic lung surgery with one-lung ventilation at a tertiary care hospital. These individuals are already indicated to receive invasive arterial blood pressure monitoring as part of their routine clinical management. No special outreach or community recruitment methods will be employed; rather, eligible patients will be identified from the hospital's surgical wards and preoperative clinics.
Who may be able to join
- Patients undergoing thoracoscopic lung surgery with one-lung ventilation
- Patients requiring invasive arterial blood pressure monitoring
Who cannot join
- Chronic obstructive pulmonary disease (COPD)
- Pulmonary hypertension
- Systemic infection
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Do End-Tidal Capnography Trends Reflect Changes in Arterial Carbon Dioxide Partial Pressure During One-Lung Ventilation for Thoracoscopic Surgery? A Prospective Observational Study
In this study, we want to find out if measuring carbon dioxide from a patient's breath (end-tidal CO₂ or ETCO₂) can reliably reflect changes in blood carbon dioxide levels (arterial CO₂ or PaCO₂) during lung surgery. Instead of just looking at individual values, we are specifically investigating whether ETCO₂ and PaCO₂ rise and fall in the same direction over time.
During lung surgery, patients often need "one-lung ventilation," where only one lung is used for breathing while the other is deflated to help the surgeon. This can cause carbon dioxide levels in the blood to change, which are typically monitored by taking blood samples. If ETCO₂ trends closely follow PaCO₂ trends, doctors may not need to take as many blood samples.
Read more
Patients in this study will already have a small tube in an artery for monitoring blood pressure. Whenever a blood test is taken, we will compare the blood CO₂ level with the ETCO₂ reading at that moment. We will also track heart rate, blood pressure, and body temperature.
By comparing these measurements, we hope to learn whether ETCO₂ reliably follows the same trends as PaCO₂, making it a useful tool for monitoring carbon dioxide levels in lung surgery with fewer blood tests.
Read the detailed description
Thoracoscopic lung surgery often requires one-lung ventilation, a technique in which only one lung is ventilated while the other is deflated to provide better access for the surgeon. This can lead to changes in blood carbon dioxide (PaCO₂) levels, which must be monitored closely to ensure patient safety. Arterial blood gas sampling remains the gold standard for measuring PaCO₂, but it is invasive, costly, and provides only intermittent data. End-tidal carbon dioxide (ETCO₂) monitoring, available through standard anesthesia devices, offers continuous, noninvasive measurement of exhaled CO₂ and can serve as a surrogate for PaCO₂.
The primary purpose of this study is to evaluate the agreement and trend correlation between ETCO₂ and PaCO₂ in patients undergoing thoracoscopic procedures with one-lung ventilation. If ETCO₂ reliably tracks changes in PaCO₂, clinicians may reduce the number of arterial blood gas samples required during these operations.
Primary objective: To evaluate the trend correlation between ETCO₂ and PaCO₂ over time.
Secondary objective: To determine the degree of agreement between ETCO₂ and PaCO₂
Study Type: Prospective, observational study. Study Setting: Operating rooms where adult patients (≥18 years old) are scheduled for thoracoscopic procedures with one-lung ventilation and require invasive arterial pressure monitoring as part of their routine care.
Duration: Each patient's participation will be limited to the intraoperative period (i.e., from anesthesia induction to the end of surgery).
Intraoperative management will follow a standardized anesthetic protocol, and arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Each time an arterial blood gas sample is taken, the corresponding ETCO₂, PaCO₂, arterial blood pressure, heart rate, and temperature values will be recorded.
Any use of inotropic or antihypertensive infusions will be documented, as such medications can influence hemodynamic stability and possibly ventilatory parameters.
The patient's demographic details (age, sex, height, weight) and the type of surgical procedure will be recorded.
Four-quadrant plots will be generated to assess the concordance of changes in ETCO₂ with changes in PaCO₂ over time.
Bland-Altman plots will be constructed to calculate the mean difference (bias) and 95% limits of agreement for each paired measurement.
What is being measured
The primary outcome is the main question the study is designed to answer.
Trend correlation between ETCO₂ and PaCO₂ measured by the concordance ratio in the four-quadrant plot
A four-quadrant plot will be generated by comparing consecutive changes (deltas) in PaCO₂ and ETCO₂. For each patient, every pair of sequential measurements will be used to calculate ΔPaCO₂ (horizontal axis) and ΔETCO₂ (vertical axis). Points in the top-right (Quadrant I) and bottom-left (Quadrant III) indicate concordant changes (both variables increased or both decreased). A "central zone" will be defined to exclude clinically negligible fluctuations (±1mmHg). The percentage of points in Quadrant I and III, relative to those outside the central zone, will be reported as the overall concordance. A concordance ratio above 90% will be considered as good trending ability.
Measured: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Trend correlation between ETCO₂ and PaCO₂ measured by the angular bias in the four-quadrant plot
In the four-quadrant plot, the angle of each data point relative to the 45-degree line will be calculated. The average of this angles will be reported as angular bias. An angular bias between ±5 degrees will be considered as good trending ability.
Measured: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Trend correlation between ETCO₂ and PaCO₂ measured by radial limits of aggreement in the four-quadrant plot
In the four-quadrant plot, the angle of each data point relative to the 45-degree line will be calculated. The radial sector relative to the 45-degree line that contains 95% of the data points will be reported as radial limits of agreement. Radial limits of agreement between ±30 degrees will be considered as good trending ability.
Measured: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Secondary outcomes (1)
Aggreement between simultaneous ETCO₂ and PaCO₂ values measured by limits of aggreement in Bland-Altman plot
A Bland-Altman plot will be used to assess agreement between ETCO₂ and PaCO₂. For each paired measurement, the difference between ETCO₂ and PaCO₂, and the average of ETCO₂ and PaCO₂ will be calculated. Each point will be plotted with the difference on the vertical axis against the average on the horizontal axis. The mean difference (bias) and 95% limits of agreement (mean difference ± 1.96 × Standard deviation of the difference) will then be calculated. Limits of aggreement between ±4 mmHg will be considered as good aggreement.
Measured: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Feb 2025
- Study start1 Apr 2025 (estimated)
- Primary completion1 Jul 2025 (estimated)
- Study completion10 Jul 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Video-Assisted Thoracoscopic SurgeryStudies 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
- 115 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Koç University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Kamil Darcin, Koç University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06835894
- Sponsor's protocol ID
- 2024.269.IRB1.033
- Status last verified
- Feb 2025
- First submitted
- 14 Feb 2025
- Last updated
- 19 Feb 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Feb 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Do End-Tidal Capnography Trends Reflect Changes in Arterial Carbon Dioxide Partial Pressure During One-Lung Ventilation for Thoracoscopic Surgery? A Prospective Observational Study
- ClinicalTrials.gov ID
- NCT06835894
- Acronym / sponsor ID
- 2024.269.IRB1.033
- Conditions
- Video-Assisted Thoracoscopic Surgery, One-Lung Ventilation, Capnography, Blood Gas Analysis
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 115 participants (estimated)
- Lead sponsor
- Koç UniversityUniversity, hospital or other
- Study start
- 1 Apr 2025 (estimated)
- Primary completion
- 1 Jul 2025 (estimated)
- Study completion
- 10 Jul 2025 (estimated)
- First posted
- 19 Feb 2025 (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.
In this study, we want to find out if measuring carbon dioxide from a patient's breath (end-tidal CO₂ or ETCO₂) can reliably reflect changes in blood carbon dioxide levels (arterial CO₂ or PaCO₂) during lung surgery. Instead of just looking at individual values, we are specifically investigating whether ETCO₂ and PaCO₂ rise and fall in the same direction over time.
During lung surgery, patients often need "one-lung ventilation," where only one lung is used for breathing while the other is deflated to help the surgeon. This can cause carbon dioxide levels in the blood to change, which are typically monitored by taking blood samples. If ETCO₂ trends closely follow PaCO₂ trends, doctors may not need to take as many blood samples.
Patients in this study will already have a small tube in an artery for monitoring blood pressure. Whenever a blood test is taken, we will compare the blood CO₂ level with the ETCO₂ reading at that moment. We will also track heart rate, blood pressure, and body temperature.
By comparing these measurements, we hope to learn whether ETCO₂ reliably follows the same trends as PaCO₂, making it a useful tool for monitoring carbon dioxide levels in lung surgery with fewer blood tests.
Detailed description
Thoracoscopic lung surgery often requires one-lung ventilation, a technique in which only one lung is ventilated while the other is deflated to provide better access for the surgeon. This can lead to changes in blood carbon dioxide (PaCO₂) levels, which must be monitored closely to ensure patient safety. Arterial blood gas sampling remains the gold standard for measuring PaCO₂, but it is invasive, costly, and provides only intermittent data. End-tidal carbon dioxide (ETCO₂) monitoring, available through standard anesthesia devices, offers continuous, noninvasive measurement of exhaled CO₂ and can serve as a surrogate for PaCO₂.
The primary purpose of this study is to evaluate the agreement and trend correlation between ETCO₂ and PaCO₂ in patients undergoing thoracoscopic procedures with one-lung ventilation. If ETCO₂ reliably tracks changes in PaCO₂, clinicians may reduce the number of arterial blood gas samples required during these operations.
Primary objective: To evaluate the trend correlation between ETCO₂ and PaCO₂ over time.
Secondary objective: To determine the degree of agreement between ETCO₂ and PaCO₂
Study Type: Prospective, observational study. Study Setting: Operating rooms where adult patients (≥18 years old) are scheduled for thoracoscopic procedures with one-lung ventilation and require invasive arterial pressure monitoring as part of their routine care.
Duration: Each patient's participation will be limited to the intraoperative period (i.e., from anesthesia induction to the end of surgery).
Intraoperative management will follow a standardized anesthetic protocol, and arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
Each time an arterial blood gas sample is taken, the corresponding ETCO₂, PaCO₂, arterial blood pressure, heart rate, and temperature values will be recorded.
Any use of inotropic or antihypertensive infusions will be documented, as such medications can influence hemodynamic stability and possibly ventilatory parameters.
The patient's demographic details (age, sex, height, weight) and the type of surgical procedure will be recorded.
Four-quadrant plots will be generated to assess the concordance of changes in ETCO₂ with changes in PaCO₂ over time.
Bland-Altman plots will be constructed to calculate the mean difference (bias) and 95% limits of agreement for each paired measurement.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Participants will be drawn from the adult patient population (≥18 years) scheduled for thoracoscopic lung surgery with one-lung ventilation at a tertiary care hospital. These individuals are already indicated to receive invasive arterial blood pressure monitoring as part of their routine clinical management. No special outreach or community recruitment methods will be employed; rather, eligible patients will be identified from the hospital's surgical wards and preoperative clinics.
Key inclusion criteria (2 listed)
- Patients undergoing thoracoscopic lung surgery with one-lung ventilation
- Patients requiring invasive arterial blood pressure monitoring
Key exclusion criteria (3 listed)
- Chronic obstructive pulmonary disease (COPD)
- Pulmonary hypertension
- Systemic infection
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
Trend correlation between ETCO₂ and PaCO₂ measured by the concordance ratio in the four-quadrant plot
Time frame: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
A four-quadrant plot will be generated by comparing consecutive changes (deltas) in PaCO₂ and ETCO₂. For each patient, every pair of sequential measurements will be used to calculate ΔPaCO₂ (horizontal axis) and ΔETCO₂ (vertical axis). Points in the top-right (Quadrant I) and bottom-left (Quadrant III) indicate concordant changes (both variables increased or both decreased). A "central zone" will be defined to exclude clinically negligible fluctuations (±1mmHg). The percentage of points in Quadrant I and III, relative to those outside the central zone, will be reported as the overall concordance. A concordance ratio above 90% will be considered as good trending ability.
Trend correlation between ETCO₂ and PaCO₂ measured by the angular bias in the four-quadrant plot
Time frame: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
In the four-quadrant plot, the angle of each data point relative to the 45-degree line will be calculated. The average of this angles will be reported as angular bias. An angular bias between ±5 degrees will be considered as good trending ability.
Trend correlation between ETCO₂ and PaCO₂ measured by radial limits of aggreement in the four-quadrant plot
Time frame: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
In the four-quadrant plot, the angle of each data point relative to the 45-degree line will be calculated. The radial sector relative to the 45-degree line that contains 95% of the data points will be reported as radial limits of agreement. Radial limits of agreement between ±30 degrees will be considered as good trending ability.
1 secondary outcome
Aggreement between simultaneous ETCO₂ and PaCO₂ values measured by limits of aggreement in Bland-Altman plot
Time frame: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.
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 19 Feb 2025.
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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.
Questions about this trial
What is this clinical trial studying?
An observational study of Video-Assisted Thoracoscopic Surgery and One-Lung Ventilation, run by Koç 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 2 inclusion and 3 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 19 Feb 2025. 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?
Contact Muhammet S Söğüt, Anesthesiologist (00905056183219, selmansogut@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Trend correlation between ETCO₂ and PaCO₂ measured by the concordance ratio in the four-quadrant plot (time frame: During the surgery of the patient, arterial blood gas samples will be drawn at the anesthesiologist's discretion whenever clinically indicated.). The study lists 3 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 19 Feb 2025.