Intraocular Pressure and Optic Nerve Sheath Diameter Changes at Different PEEP Levels

Study Overview
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Brief Summary
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Positive end-expiratory pressure (PEEP) is sometimes used during perioperative period, as it has favourable effects on lung mechanics. Unfortunately, it has some negative effects on the patients, like increased intraabdominal, intrathoracic, intracranial and intraocular pressures. In this study the investigators aimed to investigate the effects of different PEEP levels on the patients' intraocular and intracranial pressures. Intraocular pressure will be measured by ocular tonometry, and intracranial pressure will be estimated by optic nerve sheath diameter measurement. The measurements will be performed in the operating room in the patients undergoing laparotomic surgery.

Official Title
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Intraocular Pressure and Optic Nerve Sheath Diameter Changes at Different Positive End-expiratory Pressure Applications in Laparotomic Surgery

Conditions
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Intraocular Pressure, Intracranial Pressure, Positive End-expiratory Pressure

Intervention / Treatment
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* Other: Positive end-expiratory pressure


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing laparotomy for gastrointestinal surgery American Society of Anesthesiologists (ASA) 1 or 2 physical status Elective surgery Exclusion Criteria: Patients with glaucoma ASA 3 or over physical status Emergency surgery

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PEEP 5<br> | Other: Positive end-expiratory pressure<br>* Different levels of positive end-expiratory pressure (i.e., 5, 10 and 15 cm H2O) will be applied to the groups.<br>|
| Experimental: PEEP 10<br> | Other: Positive end-expiratory pressure<br>* Different levels of positive end-expiratory pressure (i.e., 5, 10 and 15 cm H2O) will be applied to the groups.<br>|
| Experimental: PEEP 15<br> | Other: Positive end-expiratory pressure<br>* Different levels of positive end-expiratory pressure (i.e., 5, 10 and 15 cm H2O) will be applied to the groups.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in intraocular pressure | The physiological value for intraocular pressure is 10-20 mm Hg. Changes in intraocular pressure will be observed throughout the surgery, as will its relationship with the positive end-expiratory pressure application. | Throughout the operation (usually about 1.5 hours). | 
| Changes in optic nerve sheath diameter | Changes in optic nerve sheath diameter will be observed throughout the surgery, as will its relationship with the positive end-expiratory pressure application. | Throughout the operation (usually about 1.5 hours). | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Intraocular pressure, Optic nerve sheath diameter, Positive end-expiratory pressure