الفهرس 
Physiological Aspects
Factors affecting IOPOnly 14 pages are availabe for public view
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Abstract
Regional anesthesia is commonly used for ophthalmic
surgery. Various ophthalmic surgeries require a potent motor
blockade (akinesia) of the eyeball and eyelids.
Sub-Tenon’s anesthesia, sometimes also called
parabulbar anesthesia, places the injection into the episcleral
space. This allows the local anesthetic to spread circularly all
around the scleral portion of the globe, thus accounting for
high-quality analgesia of the whole globe with relatively low
volumes injected (usually 6 mL).
Clonidine’s addition to local anesthetic in retrobulbar
block has several advantages: it decreases IOP, enhances
anesthesia and akinesia and increases intraoperative sedation.
The duration of lid and globe akinesia, globe analgesia and
anesethesia was significantly increased with clonidine in
peribulbar block.
In our study we compared the effect of addition of
clonidine to mepivacaine 3% in sub-tenon’s block as regard
efficacy, safety and satisfaction of the patient. 60 patients were allocated randomly in two equal groups
30 patients each.
Patients of Group A (Control group) received subTenon’s block using local anesthetic mixture of 5 ml
Mepivacaine 3% solution with 1 ml normal saline 0.9%
containing hyaluronidase 75 I.U.
For patients belonging to Group B (Clonidine group)
received sub-Tenon’s block using local anesthetic mixture of
5ml Mepivacaine 3% solution with 75µg clonidine (0.5 ml)
plus 0.5 ml normal saline 0.9% containing hyaluronidase 75
I.U.
Recorded data included motor blockade (akinesia) was
used as the main index of anesthesia effectiveness. Patientreported pain during administration of anesthesia, during
surgery, and after surgery (during the first six postoperative
hours) was recorded, sedation level was monitored during the
procedure and during the first two postoperative hours,
patients’ global satisfaction level was assessed. Arterial blood
pressure, heart rate, respiratory rate and oxygen saturation
were evaluated after local anesthetic injection for two hours.
At the end, complications were recorded. The results showed that 75µg clonidine has prolonged
postoperative analgesia with good sedation level and
hemodynamic stability when added to mepivacaine 3% in subtenon’s block for ophthalmic anterior segment surgery with no
increase in incidence of complications.