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Optic Nerve Sheath DiameterNCT07085949

Effect of Different Positive End-Expiratory Pressure (PEEP) Levels on Optic Nerve Sheath Diameter

An observational study of Optic Nerve Sheath Diameter, run by Izmir City Hospital at 1 site in Turkey (Türkiye).

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The goal of this prospective observational study is to evaluate the effects of different PEEP values on the optic nerve sheath diameter (ONSD), a noninvasive indicator of intracranial pressure (ICP), in patients undergoing vertebral surgery. Read more about this study

Who is it for?
Ages 18 to 65 years
Conditions the study is for
Optic Nerve Sheath Diameter
What is being tested?
5 cmH2O PEEP and 10 cmH2O PEEP
How many people
105 participants
Where
1 siteTurkey (Türkiye)
Study dates
30 Jul 2025to 2 Jan 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 to 65 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: patients undergoing elective

Who may be able to join

  • Age between 18-65 years
  • ASA I, II, III
  • Patients undergoing elective vertebral surgery in the prone position

Who cannot join

  • Patients were defined as having a hemoglobin concentration below 9 g/dL
  • Congestive heart failure
  • Uncontrolled hypertension
  • Severe COPD
  • Pulmonary edema
  • Cerebrovascular disease
Show all 10Show fewer
  • Those who have had carotid stenosis or surgery
  • Hemodynamic instability
  • Pregnant women
  • Those who did not wish to participate in the study.

Trial locations and contacts

1 site in 1 country.

Turkey (Türkiye)1 site

  • Izmir City Hospital

    Izmir, bayraklı, 35100

Other trials in Turkey (Türkiye)

About this study

Official title: Evaluation of the Effect of Different Positive End-Expiratory Pressure (PEEP) Levels on Optic Nerve Sheath Diameter in Patients Undergoing Vertebral Surgery; Prospective Observational Study

The goal of this prospective observational study is to evaluate the effects of different PEEP values on the optic nerve sheath diameter (ONSD), a noninvasive indicator of intracranial pressure (ICP), in patients undergoing vertebral surgery. The main question it aims to answer is how mechanical ventilation setting of 5 and 10 cmH2O PEEP effect optic nerve sheath diameter after surgery at extubation.

Read the detailed description

During general anesthesia, endotracheal intubation can cause varying degrees of alveolar collapse, particularly in the lower lung regions, in 15-20% of cases. Postoperative atelectasis and pulmonary infections are responsible for both prolonged hospital stays and increased mortality and morbidity. Positive end-expiratory pressure (PEEP) combined with low tidal volume, defined as lung-protective ventilation strategies, is used in anesthesia practice because it prevents pulmonary barotrauma, improves pulmonary function, and reduces postoperative pulmonary complications. PEEP can prevent atelectasis and reduce the risk of ventilator-associated lung injury. PEEP at 10 cmH2O or less can be used without causing a significant increase in intracranial pressure or a significant decrease in cerebral perfusion pressure.

For years, low PEEP was used in neurosurgery and neurosurgical intensive care patients, considering that PEEP could increase ICP. However, recent studies in normovolemic patients without hypotension have shown that even with increased PEEP, no clinically significant increase in ICP was observed.

The optic nerve is anatomically an extension of the central nervous system. Cerebrospinal fluid (CSF) circulates within this extension, which is surrounded by dura mater. Therefore, noninvasive ultrasonographic measurement of optic nerve sheath diameter (ONSD) has been shown to be effective in detecting increased intracranial pressure (ICP) due to the reflection of changes in subarachnoid space pressure and CSF on the optic nerve sheath. An optic nerve sheath diameter greater than 6 mm is a noninvasive indicator of increased intracranial pressure.

The effect of positive end-expiratory pressure (PEEP) on optic nerve sheath diameter in patients undergoing vertebral surgery will be evaluated.

Optic nerve sheath diameter measurements will be taken twice with ultrasound, once before surgery in the preoperative waiting room and once after surgery in the postoperative recovery unit.

Hemodynamic data (systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate, peripheral oxygen saturation), and PEEP values during anesthesia will be recorded on the anesthesia observation form.

Being tested
5 cmH2O PEEP, 10 cmH2O PEEP
Keywords
Optic nerve sheath diameter, Intracranial Pressure Increase, spinal surgery
Medical subject headings
Intracranial Hypertension

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 5 cmH2O PEEPOther

    5 cmH2O PEEP will be administered during mechanical ventilation

  • 10 cmH2O PEEPOther

    10 cmH2O PEEP will be administered during mechanical ventilation

Study groups in NCT07085949
Study groupRoleWhat they receive
PEEP 55 cmH2O PEEP will be administered during mechanical ventilation
Receives: Other: 5 cmH2O PEEP
PEEP 1010 cmH2O PEEP will be administered during mechanical ventilation
Receives: Other: 10 cmH2O PEEP

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Optic nerve sheath diameter measurement after extubation

    optic nerve sheath diameter will be measured at the end of the surgery after extubation

    Measured: just after extubation

Secondary outcomes (55)

  1. heart rate0

    Measured: pre-induction

  2. heartrate1

    Measured: up to 5 minutes after anesthesia induction

  3. heartrate2

    Measured: up to 10 minutes after anesthesia induction

  4. heartrate3

    Measured: up to 15 minutes after anesthesia induction

  5. heartrate4

    Measured: up to 5 minutes after prone position

  6. heartrate5

    Measured: up to 10 minutes after prone position

  7. heartrate6

    Measured: up to 15 minutes after prone position

  8. heartrate7

    Measured: up to 30 minutes after prone position

  9. heartrate8

    Measured: up to 1 hour after prone position

  10. heartrate9

    Measured: up to 2 hour after prone position

  11. heartrate10

    Measured: up to 3 hour after prone position

  12. mean arterial pressures0

    Measured: pre induction

  13. mean arterial pressures1

    Measured: up to 5 minutes after anesthesia

  14. mean arterial pressures2

    Measured: up to 10 minutes after anesthesia induction

  15. mean arterial pressures3

    Measured: up to 15 minutes after anesthesia induction

  16. mean arterial pressures4

    Measured: up to 5 minutes after prone position

  17. mean arterial pressures5

    Measured: up to 10 minutes after prone position

  18. mean arterial pressures6

    Measured: up to 15 minutes after prone position

  19. meanarterialpressures7

    Measured: up to 30 minutes after prone position

  20. meanarterialpressures8

    Measured: up to 1 hour after prone position

  21. meanarterialpressures9

    Measured: 2 hour after prone position

  22. meanarterialpressures10

    Measured: 3 hour after prone position

  23. diastolicpressures0

    Measured: pre induction

  24. diastolicpressures1

    Measured: up to 5 minutes after anesthesia induction

  25. diastolicpressures2

    Measured: up to 10 minutes after anesthesia indüction

  26. diastolicpressures3

    Measured: up to 15 minutes after anesthesia induction

  27. diastolicpressures4

    Measured: up to 5 minutes after prone position

  28. diastolicpressures5

    Measured: up to 10 minutes after prone position

  29. diastolicpressures6

    Measured: up to 15 minutes after prone position

  30. diastolicpressures7

    Measured: up to 30 minutes after prone position

  31. diastolicpressures8

    Measured: up to 1 hour after prone position

  32. diastolicpressures9

    Measured: up to 2 hour after prone position

  33. diastolicpressures10

    Measured: up to 3 hour after prone position

  34. systolicpressures0

    Measured: pre-induction

  35. systolicpressure1

    Measured: up to 5 minutes after anesthesia

  36. systolicpressure2

    Measured: up to 10 minutes after anesthesia

  37. systolicpressure3

    Measured: up to 15 minutes after anesthesia

  38. systolicpressure4

    Measured: up to 5 minutes after prone position

  39. systolicpressure5

    Measured: up to 10 minutes after prone position

  40. systolicpressure6

    Measured: up to 15 minutes after prone position

  41. systolicpressure7

    Measured: up to 30 minutes after prone position

  42. systolicpressure8

    Measured: up to 1 hour after prone position

  43. systolicpressure9

    Measured: up to 2 hour after prone position

  44. systolicpressure10

    Measured: up to 3 hour after prone position

  45. peripheral oxygen saturation (SpO₂)0

    Measured: pre-ınduction

  46. peripheral oxygen saturation (SpO₂)1

    Measured: up to 5 minutes after anesthesia induction

  47. peripheral oxygen saturation (SpO₂)2

    Measured: up to 10 minutes after anesthesia induction

  48. peripheral oxygen saturation (SpO₂)3

    Measured: up to 15 minutes after anesthesia induction

  49. peripheral oxygen saturation (SpO₂)4

    Measured: up to 5 minutes after prone position

  50. peripheral oxygen saturation (SpO₂)5

    Measured: up to 10 minutes after prone position

  51. peripheral oxygen saturation (SpO₂)6

    Measured: up to 15 minutes after prone position

  52. peripheral oxygen saturation (SpO₂)7

    Measured: up to 30 minutes after prone position

  53. peripheral oxygen saturation (SpO₂)8

    Measured: up to 1 hour after prone position

  54. peripheral oxygen saturation (SpO₂)9

    Measured: up to 2 hour after prone position

  55. peripheral oxygen saturation (SpO₂)10

    Measured: up to 3 hour after prone position

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted25 Jul 2025
  2. Study start30 Jul 2025
  3. Primary completion1 Jan 2026
  4. Study completion2 Jan 2026

Resources

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 crossover
Time perspective
Prospective
Enrolment
105 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07085949
Sponsor's protocol ID
OPTIC NERVE
Status last verified
Feb 2026
First submitted
17 Jul 2025
Last updated
24 Feb 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

An observational study of Optic Nerve Sheath Diameter, run by Izmir City Hospital 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 10 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 24 Feb 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?

Optic nerve sheath diameter measurement after extubation (time frame: just after extubation). 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 NCT07085949.

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 24 Feb 2026.

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