Regional Anesthesia, Eye And Tracheal Blocks

Front 1

WHERE DO ALL THE VESSELS COMING INTO THE EYE GO THROUGH?

Back 1

through the apex

Front 2

Extraocular muscles

Back 2

4 rectus
Medial
Lateral
Inferior
Superior
2 oblique
Inferior
Superior
We need to know these muscles. Extraocular they form the muscular cone that we inject medicine into. They function rectus pull the eye in the different direction. The oblique the eyes look up and down

Front 3

Sensory innervation
of the eye

Back 3

Ophthalmic nerve
Branch of trigeminal (V)
Enters through muscular cone

Front 4

Motor innervation

Back 4

Trochlear (IV); superior oblique
Only nerve that doesn’t enter cone
Abducens (VI); lateral rectus
Oculomotor (III); other extraocular muscles

Front 5

Important structures inside muscular cone

Back 5

Optic nerve
Blood vessels
Autonomic, sensory and motor nerves

Front 6

NORMAL INTRAOCULAR PRESSURE

Back 6

Normal = 10 – 22 mmHg

Intraocular is relatively close to ICP. Careful with people with glaucoma

Front 7

Retrobulbar block:

Back 7

Now modification recommended to maintain neutral gaze
Local is injected behind the globe, into the cone formed by the extraocular muscles

Front 8

Complications of Retrobulbar Block

Back 8

Oculocardiac Reflex
“Five and dime” reflex
Afferent= trigeminal (CN V)
Efferent= vagus (CN X)
Retrobulbar hemmorhage
Puncture of the globe
Intra-arterial injection (what are s/s?)**
Optic nerve sheath injection (s/s?)
Direct optic nerve trauma
Injury to extraocular muscles

Front 9

OCULOCARDIAC REFLEX

Back 9

They have akinesia of the eye, they won’t be able to follow your finger. Know these complications for the test. This reflex can be caused by doing an eyeblock

Front 10

. Intraarterial injection

Back 10

artery that leaves to go directly to the brain, they will begin to convulse and seize immediately, cardiac instability

Front 11

Optic nerve SHEATH injection, s/s

Back 11

take about 3-7 minutes. Apnea, hypotension, takes longer they may have seizures just like the arterial injection. Treatment is intubation and supportive care until the anesthesia wears off. Stop the stimulus, because the pressure on the globe and traction on the medial rectus muscle. Most common is bradycardia, hypercarbia, or hypoxia. Stop the stimulus and usually the heart rate will come back up. Optic sheath there is a little time delay.

Front 12

Avoid retrobulbar blocks with

Back 12

Extreme myopia shape of the nerves in the back you can’t stick a needle back there, they will do a peribulbar block with this.
Bleeding disorders
Open eye injuries penetrating injuries, you will increase the pressure

Front 13

Retrobulbar block may require additional facial nerve (VII) block to prevent blinking

Back 13

Most commonly Van Lindt block
You may get complete akinesia of the eye and but they may still be able to squint their eyes. In this case you will have to do an additional block of the facial block.

Front 14

Peribulbar Block

Back 14

The patient lies supine and is asked to look directly ahead focusing on a fixed point on the ceiling, so that the eyes are in the neutral position***** (some still advocate supranasal gaze)

Front 15

Hyaluronidase,

Back 15

it helps the local anesthetic get absorbed into the tissues. 2 injections are required for this and it is safer.

Front 16

PERIBULBAR BLOCK

Back 16

2 transconjuctival peribulbar injections are usually required
If you feel resistance you are either in the globe or in the muscle.
Pressure is usually applied by mechanical device or finger pressure with gauze over the lid
Assessment of block occurs at approx. 20 minutes

Front 17

Signs of successful block

Back 17

Ptosis (drooping of the upper lid with inability to open the eyes)
Either no eye movement or minimal movement in any direction (akinesia)
Inability to fully close the eye once opened

Front 18

Peribulbar vs. retrobulbar

Back 18

In contrast to the retrobulbar block the needle does NOT penetrate the cone formed by the extraocular muscles (safer for this reason)
Advantages: less risk of globe penetration, as well as optic nerve and artery. Less pain on injection. Excellent akinesia of eyelids with out additional block
Disadvantages: slower onset, increased ecchymosis

Front 19

Sub-Tenon’s block

Back 19

Most often for postoperative pain
Topical anesthetic applied
Small opening in Tenon’s capsule
Blunt cannula used
3-5 cc’s local
Capsule that encloses the globe. This will stop the patient from constantly messing with their eye. Post op analgesia

Front 20

AIRWAY BLOCKS

Back 20

Requires extensive pt preparation
Verbal
Select pre-medications
Antisialogogue
Topicalization (lidocaine)
Cotton pledgettes
Inhalation/aerosolized
Nebulizer/atomizer
Advantage
disadvantage

Front 21

Branches of glossopharyngeal nerve
Lingual
Pharyngeal

Back 21

Provide sensation to posterior 1/3 of tongue and oropharynx
Use 25g. needle and inject 2 cc local into base of palatoglossal arch (aka anterior tonsillar pillar)
Alternatively may block externally @ angle of mandible and mastoid process (5-7 cc)
Careful close proximity to the carotid

Front 22

Superior laryngeal nerve block

Back 22

Often can block with inhalation/topical
Bilateral injections at level of greater cornu of hyoid bone
25 g. 5/8 in. needle
Anteroinferomedial direction until contact with greater cornu
Walk off inferior border retract slightly and inject 2cc local (2%lidocaine)
This is sensory and we don’t want them to have a laryngospasm.

Front 23

Transtracheal block

Back 23

Blocks recurrent laryngeal nerve
Cannot perform bilateral blockade due to upper airway obstruction
Pt extends neck
Identify and penetrate cricothyroid membrane
Aspirate (air) because you are in the trachea
Inject 4cc of 4% lidocaine @ end expiration
Instruct pt to then deep breath cough will distribute local throughout trachea
Caution because all protective reflexes are now absent!!!!!!!
Recurrent laryngeal nerve is motor but sensory below the cords.