Cerebral PerfusionNCT07270341
Evaluation of Cerebral Oxygenation During Orthopedic Surgeries Performed in the Beach Chair Position Under General Anesthesia
An observational study of Cerebral Perfusion and Cerebral Oxygenation, run by Akdeniz University at 1 site in Turkey (Türkiye).
Trial summary
The goal of this observational study is to determine the correlation between cerebral oxygenation values measured by near-infrared spectroscopy (NIRS) and other routine monitoring parameters in patients placed in the semi-sitting position. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cerebral Perfusion, Cerebral Oxygenation, Hemodynamic Monitoring
- What is being tested?
- Near-Infrared Spectroscopy (NIRS) Monitoring
- How many people
- 59 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Oct 2024to 30 May 2026
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adult patients (18 years and older, ASA I-III) undergoing orthopedic surgery in the semi-sitting position, monitored for cerebral oxygenation (NIRS), invasive arterial pressure, and routine intraoperative parameters.
Who may be able to join
- Patients scheduled for orthopedic surgery in the semi-sitting position
- ASA physical status I-III
- Voluntary participation with informed consent
Who cannot join
- Patients younger than 18 years
- Patients who do not provide consent
- History of cerebral ischemia
- History of head trauma
- Previous neurosurgical intervention
- Documented carotid stenosis ≥90%
- Previous neck surgery
Trial locations and contacts
1 site in 1 country.
About this study
The goal of this observational study is to determine the correlation between cerebral oxygenation values measured by near-infrared spectroscopy (NIRS) and other routine monitoring parameters in patients placed in the semi-sitting position.
The primary questions investigated are :
Read more
Do NIRS values correlate with heart rate, invasive mean arterial pressure, and end-tidal carbon dioxide?
Do NIRS values reflect changes observed in arterial blood gas analysis?
Are cerebral perfusion-related parameters associated with patients' comorbidities such as diabetes, obesity, and hypertension?
Researchers will compare routine noninvasive monitoring (heart rate, blood pressure, peripheral oxygen saturation) with invasive arterial monitoring and NIRS to assess whether NIRS provides additional information for evaluating cerebral perfusion.
Participants will be monitored for:
Heart rate
Invasive mean arterial pressure
End-tidal carbon dioxide
Arterial blood gas changes
Cerebral oxygenation with NIRS
Patients' comorbidities (e.g., diabetes, obesity, hypertension) will also be recorded, and their association with perfusion-related parameters will be analyzed.
Read the detailed description
Semi-sitting (beach chair) position is commonly used during orthopedic surgeries such as shoulder arthroscopy, clavicle fracture fixation, and proximal humerus operations. However, this position is associated with a risk of cerebral hypoperfusion due to gravitational redistribution of blood volume, leading to decreased mean arterial pressure at the brain level. This can result in severe complications such as visual loss, ischemic stroke, and even brain death.
Routine noninvasive monitoring methods, including heart rate, blood pressure, and peripheral oxygen saturation, are standard during anesthesia. Because of the frequent occurrence of hypotension in this position, invasive arterial pressure monitoring is recommended to detect and manage hemodynamic fluctuations more precisely. Near-infrared spectroscopy (NIRS) is a noninvasive method that allows continuous measurement of cerebral oxygenation and can identify early reductions in cerebral perfusion that may not yet be reflected in traditional monitoring parameters.
The aim of this prospective observational cohort study is to determine the correlation between cerebral oxygenation measured by NIRS and other hemodynamic parameters (heart rate, invasive mean arterial pressure, end-tidal carbon dioxide) as well as arterial blood gas analysis during orthopedic surgery performed in the semi-sitting position. Additionally, the study will evaluate the relationship between cerebral perfusion parameters and patients' comorbidities (e.g., diabetes, hypertension, obesity, and other chronic conditions) to identify potential risk factors for cerebral desaturation in this surgical position.
The study will be conducted in a single tertiary academic center. A total of 30 adult patients (ASA I-III), aged 18 years or older, scheduled for elective orthopedic surgery in the semi-sitting position will be enrolled. Standard anesthesia care will be applied to all patients, and no additional intervention will be performed beyond routine monitoring. Data collection will include continuous NIRS measurements, invasive arterial pressure, heart rate, peripheral oxygen saturation, end-tidal CO₂, and arterial blood gas results.
Statistical analysis:
Descriptive statistics will be presented as means and standard deviations for continuous variables, and frequencies for categorical variables. Normality will be assessed using the Kolmogorov-Smirnov test. Correlations between NIRS values and other parameters (mean arterial pressure, ETCO₂, heart rate, blood gas values) will be analyzed using Pearson correlation coefficients for normally distributed variables. Group comparisons will be performed using paired t-tests for parametric data and Mann-Whitney U tests for nonparametric data. Bonferroni correction will be applied where multiple comparisons are made. A p-value of <0.05 will be considered statistically significant.
Sample size was calculated using G*Power (version 3.1.9.7) with a power of 80%, alpha of 0.05, and a medium effect size (f=0.25), resulting in a minimum of 28 patients required. Data will be analyzed using SPSS version 15.0.
This study aims to contribute to identifying optimal intraoperative monitoring strategies for maintaining cerebral perfusion during orthopedic procedures performed in the semi-sitting position, particularly in patients with multiple comorbidities.
- Conditions
- Cerebral Perfusion, Cerebral Oxygenation, Hemodynamic Monitoring, Semi-sitting Position, Orthopedic Surgical Procedures
- Being tested
- Near-Infrared Spectroscopy (NIRS) Monitoring
- Keywords
- cerebral perfusion, semi-sitting position, orthopedic surgery, cerebral oxygenation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Near-Infrared Spectroscopy (NIRS) MonitoringDiagnostic test
Also called Invasive Arterial Catheterization, Routine intraoperative monitoring including heart rate, non-invasive blood pressure, peripheral oxygen saturation, and end-tidal CO₂.
Cerebral oxygenation will be monitored using NIRS in addition to standard intraoperative monitoring (heart rate, invasive arterial pressure, end-tidal CO₂, and blood gas analysis).
| Study group | Role | What they receive |
|---|---|---|
| Orthopedic Surgery Patients in Semi-sitting Position | ASA I-III patients undergoing orthopedic surgery in the semi-sitting position, monitored with NIRS, invasive arterial pressure, and routine parameters. Receives: Diagnostic Test: Near-Infrared Spectroscopy (NIRS) Monitoring |
What is being measured
The primary outcome is the main question the study is designed to answer.
Correlation Between Cerebral Oxygenation (rSO₂) Measured by NIRS and Systemic Oxygenation
The correlation between intraoperative cerebral oxygenation (regional cerebral oxygen saturation, rSO₂) (%)-measured non-invasively using near-infrared spectroscopy (NIRS) -and simultaneous systemic oxygenation assessed using arterial blood gas analysis, including: Arterial pH, PaO₂ (mmHg) and PaCO₂ (mmHg)
Measured: From pre-induction baseline through post-induction and positional measurements, followed by repeated assessments every 30 minutes until the end of surgery.
Correlation Between Cerebral Oxygenation (rSO₂) Measured by NIRS and Hemodynamic Parameters (Heart Rate and Blood Pressure)
The correlation between intraoperative cerebral oxygenation (regional cerebral oxygen saturation, rSO₂) (%)-measured non-invasively using near-infrared spectroscopy (NIRS) -and systemic hemodynamic parameters.
Systemic hemodynamic parameters will include:
- Heart rate (beats per minute), monitored continuously via electrocardiography (ECG)
- Noninvasive mean arterial pressure (mmHg), measured using an automated oscillometric device
- Invasive mean arterial pressure (mmHg), obtained via an arterial catheter
Measured: From pre-induction baseline through post-induction and positional measurements, followed by repeated assessments every 30 minutes until the end of surgery.
Secondary outcomes (3)
Association of Preoperatively Documented Hypertension with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
The associations between preoperatively diagnosed hypertension with the occurrence of intraoperative reductions in regional cerebral oxygen saturation (rSO₂), defined as values falling below the normal range (60-75%).
Measured: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Association of Preoperatively Documented Diabetes Mellitus with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
The associations between preoperatively diagnosed diabetes mellitus, and the occurrence of intraoperative reductions in regional cerebral oxygen saturation (rSO₂), defined as values falling below the normal range (60-75%).
Measured: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Association of Preoperatively Documented Obesity with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
The associations between preoperative obesity-defined as a body mass index (BMI) greater than 30 kg/m²-and the occurrence of intraoperative reductions in regional cerebral oxygen saturation (rSO₂), defined as values falling below the normal range (60-75%).
Measured: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Dec 2025
- Study start1 Oct 2024
- Primary completion30 May 2026
- Study completion30 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Cerebral PerfusionStudies of the same condition, open and under way.
- More trials run by Akdeniz 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
- 59 participants (actual)
Sponsor and investigators
- Lead sponsor
- Akdeniz University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Nesil Coskunfirat, Akdeniz University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07270341
- Sponsor's protocol ID
- TBAEK-727
- Status last verified
- Sep 2026
- First submitted
- 18 Nov 2025
- Last updated
- 10 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Yu S, Bloomquist D. Can resorbable screws effectively be used in fixating bilateral sagittal split osteotomies for mandibular advancement? A randomized controlled trial. J Oral Maxillofac Surg. 2014 Nov;72(11):2273-7. doi: 10.1016/j.joms.2014.04.033. Epub 2014 May 9.
PubMed 25086478Carroll JJ, Marshall BDL, Rich JD, Green TC. Exposure to fentanyl-contaminated heroin and overdose risk among illicit opioid users in Rhode Island: A mixed methods study. Int J Drug Policy. 2017 Aug;46:136-145. doi: 10.1016/j.drugpo.2017.05.023. Epub 2017 Jun 1.
PubMed 28578864
Study at a glance
From the registry record, last updated by the sponsor on 10 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Cerebral Oxygenation During Orthopedic Surgeries Performed in the Beach Chair Position Under General Anesthesia
- ClinicalTrials.gov ID
- NCT07270341
- Acronym / sponsor ID
- TBAEK-727
- Conditions
- Cerebral Perfusion, Cerebral Oxygenation, Hemodynamic Monitoring, Semi-sitting Position, Orthopedic Surgical Procedures
- Keywords
- cerebral perfusion, semi-sitting position, orthopedic surgery, cerebral oxygenation
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 59 participants (actual)
- Lead sponsor
- Akdeniz UniversityUniversity, hospital or other
- Study start
- 1 Oct 2024 (actual)
- Primary completion
- 30 May 2026 (actual)
- Study completion
- 30 May 2026 (actual)
- First posted
- 8 Dec 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.
The goal of this observational study is to determine the correlation between cerebral oxygenation values measured by near-infrared spectroscopy (NIRS) and other routine monitoring parameters in patients placed in the semi-sitting position.
The primary questions investigated are :
Do NIRS values correlate with heart rate, invasive mean arterial pressure, and end-tidal carbon dioxide?
Do NIRS values reflect changes observed in arterial blood gas analysis?
Are cerebral perfusion-related parameters associated with patients' comorbidities such as diabetes, obesity, and hypertension?
Researchers will compare routine noninvasive monitoring (heart rate, blood pressure, peripheral oxygen saturation) with invasive arterial monitoring and NIRS to assess whether NIRS provides additional information for evaluating cerebral perfusion.
Participants will be monitored for:
Heart rate
Invasive mean arterial pressure
End-tidal carbon dioxide
Arterial blood gas changes
Cerebral oxygenation with NIRS
Patients' comorbidities (e.g., diabetes, obesity, hypertension) will also be recorded, and their association with perfusion-related parameters will be analyzed.
Detailed description
Semi-sitting (beach chair) position is commonly used during orthopedic surgeries such as shoulder arthroscopy, clavicle fracture fixation, and proximal humerus operations. However, this position is associated with a risk of cerebral hypoperfusion due to gravitational redistribution of blood volume, leading to decreased mean arterial pressure at the brain level. This can result in severe complications such as visual loss, ischemic stroke, and even brain death.
Routine noninvasive monitoring methods, including heart rate, blood pressure, and peripheral oxygen saturation, are standard during anesthesia. Because of the frequent occurrence of hypotension in this position, invasive arterial pressure monitoring is recommended to detect and manage hemodynamic fluctuations more precisely. Near-infrared spectroscopy (NIRS) is a noninvasive method that allows continuous measurement of cerebral oxygenation and can identify early reductions in cerebral perfusion that may not yet be reflected in traditional monitoring parameters.
The aim of this prospective observational cohort study is to determine the correlation between cerebral oxygenation measured by NIRS and other hemodynamic parameters (heart rate, invasive mean arterial pressure, end-tidal carbon dioxide) as well as arterial blood gas analysis during orthopedic surgery performed in the semi-sitting position. Additionally, the study will evaluate the relationship between cerebral perfusion parameters and patients' comorbidities (e.g., diabetes, hypertension, obesity, and other chronic conditions) to identify potential risk factors for cerebral desaturation in this surgical position.
The study will be conducted in a single tertiary academic center. A total of 30 adult patients (ASA I-III), aged 18 years or older, scheduled for elective orthopedic surgery in the semi-sitting position will be enrolled. Standard anesthesia care will be applied to all patients, and no additional intervention will be performed beyond routine monitoring. Data collection will include continuous NIRS measurements, invasive arterial pressure, heart rate, peripheral oxygen saturation, end-tidal CO₂, and arterial blood gas results.
Statistical analysis:
Descriptive statistics will be presented as means and standard deviations for continuous variables, and frequencies for categorical variables. Normality will be assessed using the Kolmogorov-Smirnov test. Correlations between NIRS values and other parameters (mean arterial pressure, ETCO₂, heart rate, blood gas values) will be analyzed using Pearson correlation coefficients for normally distributed variables. Group comparisons will be performed using paired t-tests for parametric data and Mann-Whitney U tests for nonparametric data. Bonferroni correction will be applied where multiple comparisons are made. A p-value of <0.05 will be considered statistically significant.
Sample size was calculated using G*Power (version 3.1.9.7) with a power of 80%, alpha of 0.05, and a medium effect size (f=0.25), resulting in a minimum of 28 patients required. Data will be analyzed using SPSS version 15.0.
This study aims to contribute to identifying optimal intraoperative monitoring strategies for maintaining cerebral perfusion during orthopedic procedures performed in the semi-sitting position, particularly in patients with multiple comorbidities.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Orthopedic Surgery Patients in Semi-sitting Position | – | Diagnostic Test: Near-Infrared Spectroscopy (NIRS) MonitoringASA I-III patients undergoing orthopedic surgery in the semi-sitting position, monitored with NIRS, invasive arterial pressure, and routine parameters. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult patients (18 years and older, ASA I-III) undergoing orthopedic surgery in the semi-sitting position, monitored for cerebral oxygenation (NIRS), invasive arterial pressure, and routine intraoperative parameters.
Key inclusion criteria (3 listed)
- Patients scheduled for orthopedic surgery in the semi-sitting position
- ASA physical status I-III
- Voluntary participation with informed consent
Key exclusion criteria (7 listed)
- Patients younger than 18 years
- Patients who do not provide consent
- History of cerebral ischemia
- History of head trauma
- Previous neurosurgical intervention
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 |
|---|---|---|
| Near-Infrared Spectroscopy (NIRS) MonitoringAlso: Invasive Arterial Catheterization, Routine intraoperative monitoring including heart rate, non-invasive blood pressure, peripheral oxygen saturation, and end-tidal CO₂.Cerebral oxygenation will be monitored using NIRS in addition to standard intraoperative monitoring (heart rate, invasive arterial pressure, end-tidal CO₂, and blood gas analysis). | Diagnostic test | Orthopedic Surgery Patients in Semi-sitting Position |
Primary outcome
Correlation Between Cerebral Oxygenation (rSO₂) Measured by NIRS and Systemic Oxygenation
Time frame: From pre-induction baseline through post-induction and positional measurements, followed by repeated assessments every 30 minutes until the end of surgery.
The correlation between intraoperative cerebral oxygenation (regional cerebral oxygen saturation, rSO₂) (%)-measured non-invasively using near-infrared spectroscopy (NIRS) -and simultaneous systemic oxygenation assessed using arterial blood gas analysis, including: Arterial pH, PaO₂ (mmHg) and PaCO₂ (mmHg)
Correlation Between Cerebral Oxygenation (rSO₂) Measured by NIRS and Hemodynamic Parameters (Heart Rate and Blood Pressure)
Time frame: From pre-induction baseline through post-induction and positional measurements, followed by repeated assessments every 30 minutes until the end of surgery.
The correlation between intraoperative cerebral oxygenation (regional cerebral oxygen saturation, rSO₂) (%)-measured non-invasively using near-infrared spectroscopy (NIRS) -and systemic hemodynamic parameters. Systemic hemodynamic parameters will include: 1. Heart rate (beats per minute), monitored continuously via electrocardiography (ECG) 2. Noninvasive mean arterial pressure (mmHg), measured using an automated oscillometric device 3. Invasive mean arterial pressure (mmHg), obtained via an arterial catheter
3 secondary outcomes
Association of Preoperatively Documented Hypertension with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
Time frame: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Association of Preoperatively Documented Diabetes Mellitus with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
Time frame: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Association of Preoperatively Documented Obesity with Intraoperative Low Cerebral Oxygenation (rSO₂) Measured by Near-Infrared Spectroscopy
Time frame: Preoperative period for comorbidity assessment and intraoperative period for cerebral oxygenation measurements (from pre-induction baseline to the end of surgery.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Sep 2026.
- Background: PubMed 25086478Yu S, Bloomquist D. Can resorbable screws effectively be used in fixating bilateral sagittal split osteotomies for mandibular advancement? A randomized controlled trial. J Oral Maxillofac Surg. 2014 Nov;72(11):2273-7. doi: 10.1016/j.joms.2014.04.033. Epub 2014 May 9.
- Background: PubMed 28578864Carroll JJ, Marshall BDL, Rich JD, Green TC. Exposure to fentanyl-contaminated heroin and overdose risk among illicit opioid users in Rhode Island: A mixed methods study. Int J Drug Policy. 2017 Aug;46:136-145. doi: 10.1016/j.drugpo.2017.05.023. Epub 2017 Jun 1.
- Individual participant dataSharing planned: Undecided
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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.
The record lists no contact. Use the official record to reach the sponsor.
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 Cerebral Perfusion and Cerebral Oxygenation, run by Akdeniz University at 1 site in Turkey (Türkiye).
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 7 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: finished, as of the sponsor's last update on 10 Sep 2026. 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 Turkey (Türkiye). 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Correlation Between Cerebral Oxygenation (rSO₂) Measured by NIRS and Systemic Oxygenation (time frame: From pre-induction baseline through post-induction and positional measurements, followed by repeated assessments every 30 minutes until the end of surgery.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07270341, which also lists 2 linked publications.
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 10 Sep 2026.