Pediatric Caudal Injection Volume on Optic Nerve Sheath Diameter and Cerebral Oxygenation

Study Overview
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Brief Summary
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Caudal anesthesia is a commonly used neuraxial anesthesia method for children. Injection of a certain volume of fluid into the epidural space for cauda anesthesia may push some cerebrospinal fluid towards the head, which may lead to mild increase of pressures inside the head. Such mild changes are compensated well by healthy individuals and no clinical sequel is seen, however at-risk populations may be affected. We aim to see how different amounts of fluid injected into the epidural space may change two clinical parameters affected by intracranial pressure to determine if a lower volume is safer than a higher one.

Detailed Description
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Caudal epidural injection of local anesthetic solution is a common neuraxial anesthesia technique that provides excellent peri-operative analgesia in children. Unfused sacral hiatus allows for easy and safe access into the epidural space. Anatomically, injection of a certain volume of fluid over the dural sac inside the closed spinal canal can push the cerebrospinal fluid cranially. This push may lead to increased intracranial pressure. We will measure two findings affected by intracranial pressure (optic nerve sheath diameter and cerebral oxygenation) and compare the effects of two different volumes of caudal injections on these measures. Children with closed fontanelles and scheduled to undergo elective surgery, for which caudal anesthesia is an effective method for peri-operative analgesia, will be recruited for this study. Injection volume will be determined depending on the level of analgesia required for the surgical procedure. Ultrasonographic measurements of optic nerve sheath diameter and near-infrared spectrometry measurement of cerebral oxygenation will be taken before and after caudal anesthesia.

Official Title
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The Effect of Caudal Epidural Injection Volume on Optic Nerve Sheath Diameter and Cerebral Oxygenation in Pediatric Cases

Conditions
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Pediatrics, Elevated Intracranial Pressure, Anesthesia, Caudal

Intervention / Treatment
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* Procedure: Caudal anesthesia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA class 1 or 2 Scheduled for elective surgery suitable for caudal anesthesia Parental/guardian consent for caudal anesthesia and measurements obtained Closed fontanelles Exclusion Criteria: Open fontanelle Parental/guardian refusal Previous intracranial or ocular pathology Coagulapathies Variations in gross and ultrasonographic sacral anatomy Block performence to end of surgery expected to last less than 30 minutes Block volumes more than 30ml needed Laparoscopic surgery Need for long term analgesia with epidural catheter

Ages Eligible for Study
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Minimum Age: 12 Months
Maximum Age: 8 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: Screening
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Patients will receive either a low or high volume of caudal injection.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Low Volume<br>Caudal anesthesia will be performed with 0.8 ml/kg of the local anesthetic solution | Procedure: Caudal anesthesia<br>* Caudal epidural injection will be performed after induction of general anesthesia.<br>|
| Active Comparator: High Volume<br>Caudal anesthesia will be performed with 1.25 ml/kg of the local anesthetic solution | Procedure: Caudal anesthesia<br>* Caudal epidural injection will be performed after induction of general anesthesia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in optic nerve sheath diameter | Difference in the percentage change of ultrasonographic measurement of optic nerve sheath diameter between groups | From before caudal injection to immediately, 10 min, 20 min and 30 min after. | 
| Change in cerebral oxygenation | Difference in the change in near-infrared spectrometry measurement of cerebral oxygenation between the groups | From before caudal injection to immediately, 10 min, 20 min and 30 min after. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variation in optic nerve sheath diameter | Difference in the percentage change of ultrasonographic measurement of optic nerve sheath diameter in each group | From before caudal injection to immediately, 10 min, 20 min and 30 min after. | 
| Variation in cerebral oxygenation | Difference in the change in near-infrared spectrometry measurement of cerebral oxygenation in each group | From before caudal injection to immediately, 10 min, 20 min and 30 min after. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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optic nerve sheath diameter, cerebral oximetry, caudal epidural anesthesia