Eye Diseases
Conditions
Keywords
Ultrasound guided peribulbar anesthesia
Brief summary
Peribulbar anaesthesia for ocular surgery depends on the spread of local anaesthetic throught the orbit to be successful and has a relatively high failure rate. This study will examine a novel ultrasound guided approach to peribulbar anaesthesia which should extend the depostion of local anaesthetic by using a dual quadrant injection technique. The study will assess the feasibility of this technique, how successful it is and whether any obvious safety issues arise with its use.
Detailed description
Peribulbar anesthesia is widely used for anterior and posterior chamber ophthalmic procedures. It is a blind technique which is traditionally carried out by inserting a needle in the infero-lateral aspect of the orbit below the globe and injecting a volume of 8 - 12 mL of local anesthetic in the periorbital space. The goal of this inejction is to achieve akinesia and anesthesia of the eye sufficient for surgery. The technique has a relatively high failure rate of up to 30%. A failure or insufficient block requires a second or rarely a third peribulbar injection to achieve success. Ultrasound can be used to guide needles in the human body and has been successfully used in many anatomic locations for anaesthesia. This study will assess whether ultrasound can guide the block needle in ophthalmic anesthesia to deliver local anesthetic via a single entry into two discrete locations within the periorbital space - the first in the infero-lateral quadrant and the second in the infero-medial quadrant. If this can be done the investigators may achieve a higher success rate for this block with a lower volume potentially improving the quality of the block and its safety.
Interventions
PROCEDUREUltrasound guided Dual Quadrant Peribulbar Anaesthesia
Landmark Guided single injection vs Ultrasound guided dual quadrant injection
Sponsors
Sunnybrook Health Sciences Centre
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 90 Years
Healthy volunteers
No
Inclusion criteria
* ASA score less than III and ability to provide a written informed consent * 22 patients presenting for opthalmic surgery
Exclusion criteria
* Coagulation disorder or anticoagulated with INR \> 1.5 * Platelet count \< 75 X 10\*9/L * Significant Myopia (axial length \> 28mm) * Patients unable to lie supine for 2 hours * Patients with recent gas or silicone injections in/around the eye
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Block Success | 10 minutes post intervention | Block will be deemed a failure if a supplementary block is required for the operative procedure |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Block Quality (standardized Ocular Scoring System for akinesia and anaesthesia) | 5 and 10 minutes | Block will be assessed according to a standardized Ocular Scoring System for akinesia and anaesthesia at 5 minutes and 10 minutes post block. This is a composite measure |
| Block Volume | 1 minute | Total volume of local anaesthetic will be recorded. Volume for each part of the dual injection technique will also be recorded. This is a composite measure. |
| Duration of Procedure | 1 to 10 minutes | The duration of the entire procedure will be recorded |
| Complications | 6 Weeks | Any complications during the procedure or in follow up clinical visits will be recorded |
| Image Visualization | 1 minute | Operator's ability to see the needle in both the infero-lateral and infero-medial injection will be recorded. Ability to see perineural, retrobulbar and medial rectus spread of local anaesthetic will be recorded. This is a composite qualitative measure. |
Outcome results
None listed