The Influence of Prone Position for Spinal Surgery on Visual Acuity

Study Overview
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Brief Summary
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This study investigated the effect of desflurane and propofol anesthesia on visual acuity in patients in prone position for spinal surgery. Many trials have investigated the effects of different anesthetic agents on intraocular pressure, propofol may reduce intraocular pressure more than other intravenous anesthetics.

Detailed Description
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Perioperative increase in intraocular pressure can be caused by prone positioning. In addition to surgical factors, patients with glaucoma, uncontrolled hypertension, arthrosclerosis, and morbid obesity are at risk for potentially damaging optic nerve and loss of optic nerve function. Some studies found that intraocular pressure values were significantly lower in patients undergoing propofol total intravenous anesthesia than in patients undergoing desflurane anesthesia during intraoperative positional changes. Pronounced vasodilatation caused by desflurane might produced hyperaemia with higher intraocular pressure. Hemodynamic response to prone position measured by near-infrared spectroscopy (NIRS) on the prefrontal cortex could determine changes caused by prone position.

Official Title
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The Influence of Prone Position for Spinal Surgery on Visual Acuity, a Comparison of Volatile Anesthesia With Desflurane to Total Intravenous Anesthesia With Propofol

Conditions
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Vision; Disorder, Loss

Intervention / Treatment
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* Procedure: Desflurane Group
* Procedure: Propofol Group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Glasgow Coma scale 15 American Society of Anesthesiologists (ASA) Physical Status Classification System I-III spinal surgery in duration less than 3 hours sinus rhythm Exclusion Criteria: postoperative artificial ventilation serious neurological disease lung disease with hypercapnia propofol allergy

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Desflurane Group<br>Induction and anesthesia will be held by using desflurane | Procedure: Desflurane Group<br>* General anesthesia will be held using desflurane in end- tidal concentration according to target value of entropy levels (between 40 and 60).<br>|
| Experimental: Propofol Group<br>Induction and anesthesia will be held by using target-control anesthesia with propofol | Procedure: Propofol Group<br>* General anesthesia will be held using Schnider effect model for propofol (target control anesthesia). Titration will be done according to target value of entropy levels (between 40 and 60).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual injury | worsening of test for visual acuity (Rodenstock) | 48 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Desflurane, Near-infrared spectroscopy, Propofol, Spinal surgery, Prone position, Visual acuity, Visual loss