Nama : Christina Ariani TjahyonoNim : 03-012

Tugas anestesi

Retrobulbar block

Saraf yang di block pada anestesi retrobulbar ialah

1. ganglion siliaris

2. nervus siliaris

3. nervus II(optikus)

4. nervus III(okulomotorius)

5. nervus VI(abdusens)

Retrobulbar block ini dicapai dengan menggunakan agen-agen anestesi lokal yang

disuntikan ke m rectus. Anestesi lokal yang biasa digunakan untuk retrobulbar block

ialah campuran 1:1 lidocaine 2% dengan bupivacaine 0,5% atau 0,75%.

Refleks oculocardiac

Refleks oculocardiac disebut juga Aschner phenomenon, Aschner reflex, atau

Aschner-Dagnini reflex, penurunan nadi yang berhubungan dengan tarikan pada otot

ekstaokular atau penekanan bola mata. Refleks ini di teruskan oleh nervus trigeminus

dan n vagus dari ganglion parasimpatis. Jalur aferen diteruskan oleh cabang pertama dari

n trigeminus yaitu n ophtalmicus juga n maksilaris dan mandibularis. Jalur aferen ini

bersinaps dengan viseral motor nukleus dari n vagus yang terletak di formasio retikularis

di batang otak. Jalur eferen diteruskan oleh n vagus dari pusat kardiovaskuler di medula

ke jantung yang memberi pengaruh untuk mengurangi output Sinoatrial node. Reflek ini

sering terjadi pada neonatus dan anak-anak oleh karena itu perlu monitoring yang ketat

pada operasi mata pada anak-anak. Refleks ini bisa terjadi juga pada orang dewasa.

Mekanisme oculocardiac refleks

Tarikan pada otot-otot ekstraokuli atau penekanan pada bola mata

Menstimulasi ujung saraf sensoris n trigeminus

Mengirimkan sinyal melalui ganlion gasseri

Nukleus sensorik n trigeminus

Jalur aferen berlanjut sepanjang serabut internuncial di formasio retikularis

Berhubungan dengan jalur eferen nukleus motorik n vagus

Nukleus motorik n vagus berakhir pada miokardium

Gejala:

• bradiakardi,

• asistole

• hipotensi

• Apnea

• hipermotilitas gaster

Cara mengatasinya :

• dengan mengurangi tekanan pada bola mata

• pemberian anti muskarinik asetiklolin antagonis seperti atropin atau glycoprolate.

Ophthalmic Regional Anesthesia IndicationsThere are no specific indications for regional anesthesia during ophthalmic procedures. This procedure exists simply as an alternative to general or local anesthesia (LA). The choice of anesthesia should be individualized based on the patient, the procedure, and the needs of the surgeon. ContraindicationsAge less than 15 years oldProcedure lasting more than 90 minutesUncontrolled cough, tremor or convulsive disorderDisorientation or mental impairmentExcessive anxiety or claustrophobiaBleeding or coagulation disorderPerforated globe GoalsAnalgesiaAkinesiaControl of intraocular pressureAvoidance or obtundation of the oculocardiac reflex MedicationsThe most commonly used LA agents are a 1:1 mixture of 2% Lidocaine with 0.5% or 0.75% Bupivicaine.The addition of Epinephrine or Hyaluronidase is provider dependent. AnatomyExtraocular Muscles of the Eye—Six sets of muscles that control movements of the eyeball. They are the superior and inferior rectus, which move the eye up and down; the medial and lateral rectus, which move the eye to either side; and the superior and inferior oblique, which move the eye upward and outward and downward and outward.

Muscle LocationMedial Rectus Lies on the inner surfaceLateral Rectus Lies on the outer sideSuperior Rectus Lies above the eyeInferior Rectus Lies below the eyeSuperior Oblique Lies above and runs obliquelyInferior Oblique Lies below and runs obliquely

Other Skeletal Muscles of the Eye—Orbicularis oculi muscle which is attached to the deep surface of the skin and is responsible for eyelid closure, including automatic and reflex blinking action. GoalFor the LA to be delivered to the ciliary ganglion and the nerves of the eye to provide adequate blockade.For additional eye anatomy, please refer to: http://www.pitt.edu/~anat/

Types of Regional Techniques for Eye SurgeryPeribulbar (Pericone Block): LA is deposited around the eye, but not within the rectus muscle cone.Retrobulbar (Intracone Block): LA is deposited behind the eye within the rectus muscle cone itself. Peribulbar BlockA peribulbar block involves injections above and below the orbit, with LA deposited in, behind, beneath, and above the orbicularis oculi muscle, and behind the globe. Of note, the LA does not enter the confines of the cone of the rectus muscle. Therefore, the potential for intraocular injection is decreased because the anesthetic is deposited outside the muscle cone. The risk for intraconal hemorrhage and direct optic nerve injury is also decreased. Technique—Neutral Gaze PositionThe patient is asked to look at a point in the distance with the pupil in a central position.

Enter the skin at point B with a 25-27 gauge 2.5cm needle.The needle is kept perfectly vertical and penetrates approximately 1.5cm deep through the skin.The position of the skin penetration at point B is well

inferior to the orbital brim.

The needle is then walked over the orbital brim.The needle is pushed over the brim by the left thumb of the operator. Inject 1 mL of LA here to block the orbicularis oculi muscle, but…ALWAYS ASPIRATE BEFORE INJECTING!Next, advance the needle into the inferolateral peribulbar

space anterior to the equator of the globe and inject 2 ml of LA. Finally, advance the needle past the equator but still outside of the cone and inject 4 ml of LA.

Next, withdraw the needle while simultaneously injecting a small amount of local anesthetic subcutaneously.After the needle is withdrawn and the skin is anesthetized, pressure is applied to the skin against the maxillary bone.

The index finger maintains pressure on the area where the first injection was given, while the second peribulbar injection is being administered.The medial peribulbar space is entered through the caruncle just lateral to the medial canthus. The needle is advanced as it remains vertical and parallel to the laminal paparisa. Stay close to the bone, and

inject 2 mL of LA here.Finally, a third injection can be given superior and lateral to point C above the globe.Remove the needle and apply light pressure to the orbit and its contents. Retrobulbar BlockThe retrobulbar block is aimed at blocking the ciliary ganglion, ciliary nerves, and cranial nerves II, III, and VI. This is accomplished by delivering the LA into the muscle cone itself. However, cranial nerve IV is not affected, as it is located outside of the muscle cone.

TechniqueAsk the patient to look straight ahead. By looking upward or inward the needle path may approach the optic nerve, ophthalmic artery, and vein.Using a 25-27 gauge 20-35 mm needle, enter the skin at the same point as the first peribulbar injection (Point B).Advance slowly.

The needle is “walked” over the brim of the orbit and is advanced directly posteriorly. When the tip of the needle reaches the equator of the eye, it is directed upward and medially so that the tip of the needle lies directly posterior to the pupil.

The needle should only penetrate retrobulbar fat and intermuscular septum. If resistance is felt, the needle may be in muscle, optic nerve, or the wall of the eye and it should be withdrawn and redirected.

First, administer a very small test dose of LA. If the needle is in the eye, the patient will experience severe pain.Next, inject 4 ml of LA. During the injection, the upper eyelid will start to sag and the eye will bulge forward. It is important to note bulging of the upper eyelid and not

the lower eyelid. Lower eyelid bulging signals injection into the inferior peribulbar space.

Withdraw the needle and apply pressure against the maxillary bone.

Assessment of Block EfficacySigns of a successful block include:No eye movement or minimal eye movement in any directionAnalgesiaTemporary vision impairmentPtosis ComplicationsOculocardiac Reflex (involving cranial nerves V and X)—Manifested by bradycardia, junctional rhythm, or even asystole. May occur secondary to traction on the eye and ocular muscles.Hypoxia, hypercarbia, and light anesthesia potentiates this reflex and should be avoided.Atropine or glycopyrrolate can be used to treat this reflex. Inadvertent Brain Stem Anesthesia—Injection into the CSF can occur during the block due to perforation of the meningeal sheaths that surround the optic nerve.The patient may experience disorientation, amaurosis fugax (transient episodic blindness), aphasia, hemiplegia, unconsciousness, convulsions, and respiratory or cardiac arrest. Central retinal artery occlusion Puncture of the posterior globe Penetration of the optic nerve Allergic reactions Hemorrhage References Questions

Oculocardiac reflexFrom Wikipedia, the free encyclopedia

Jump to: navigation, search

The oculocardiac reflex, also known as Aschner phenomenon, Aschner reflex, or Aschner-Dagnini reflex, is a decrease in pulse rate associated with traction applied to extraocular muscles and/or compression of the eyeball. The reflex is mediated by nerve connections between the trigeminal cranial nerve and the vagus nerve of the parasympathetic nervous system. The afferent tracts derive mainly from the ophthalmic division of the trigeminal nerve, although tracts from the maxillary and mandibular division have also been documented[1]. These afferents synapse with the visceral motor nucleus of the vagus nerve, located in the reticular formation of the brain stem. The efferent portion is carried by the vagus nerve from the cardiovascular center of the medulla to the heart, of which increased stimulation leads to decreased output of the sinoatrial node [2] . This reflex is especially sensitive in neonates and children, and must be monitored, usually by an anaesthesiologist, during paediatric ophthalmological surgery, particularly during strabismus correction surgery[3]. However, this reflex may also occur with adults. Bradycardia, junctional rhythm, asystole, and very rarely death[4], can be induced through this reflex.

[edit] Treatment/prophylaxis

Removal of the inciting stimulus is immediately indicated, and is essential for successful termination of this reflex. The surgeon, or practitioner, working on the eye should be asked to cease their activity and release the applied pressure or traction on the eyeball. This often results in the restoration of normal sinus rhythm of the heart. If not, the use of an anti-muscarinic acetylcholine (ACh) antagonist, such as atropine or glycopyrolate, will likely successfully treat the patient and permit continuation of the surgical procedure. In extreme cases, such as the development of asystole, aggressive cardiopulmonary resuscitation may be required.

[edit] References

1. ̂ Lang S, Lanigan D, van der Wal M (1991). "Trigeminocardiac reflexes: maxillary and mandibular variants of the oculocardiac reflex.". Can J Anaesth 38 (6): 757–60. PMID 1914059.

2. ̂ Paton J, Boscan P, Pickering A, Nalivaiko E (2005). "The yin and yang of cardiac autonomic control: vago-sympathetic interactions revisited.". Brain Res Brain Res Rev 49 (3): 555–65. doi:10.1016/j.brainresrev.2005.02.005. PMID 162

Retrobulbar Blocks

(Originally posted 18 January 1999 on About Anesthesiology)

INTRODUCTIONMany ophthalmologic procedures can be performed with retrobulbar blockade. This block can provide adequate anesthesia, akinesia and control of introcular pressure as well as postoperative analgesia. Most anesthesiologists do not perform these blocks, preferring to let the ophthalmologist place the block prior to beginning of surgery. In these cases, the anesthesiologist often provides sedation to make the block more tolerable/comfortable for the patient. In some centers, however, the anesthesiologists are the ones actually placing the blocks. In any case, it is a handy technique to be familiar with.

ANATOMY:The ciliary ganglion, a parasympathetic ganglion, lies approximately 1 cm from the posterior boundary of the orbit between the lateral surface of the optic nerve and the ophthalmic artery. Parasympathetic fibers originating in the oculomotor nerve and postganglionic fibers supply the ciliary body and pupillary sphincter muscles.

The nasociliary nerve, a branch of the ophthalmic nerve, supplies sensory innervation of the cornea, iris, and ciliary body by way of the short ciliary nerves (these short viliary nerves are 6-10 small filaments that run with the ciliary arteries).

Retrobulbar block is aimed at blocking the ciliary ganglion, ciliary nerves, and cranial nerves II, II and VI. Cranial nerve IV is not affected since it lies outside the muscle cone. When the block is performed, the local anesthetic is delivered within the muscle cone itself.

TECHNIQUE OF RETROBULBAR BLOCK:In the adult, the distance to the ciliary ganglion from the skin is about 3.5cm. Most commonly, a 25 gauge, 35mm needle is used to reduce the risk of passage beyond the ciliary ganglion. Advancement too far can result in puncture of the vessels in the apex of the orbit.

Steps in the blockade are as follows:

1. Palpate the inferolateral margin of the orbit and make a skin wheal.

2. Ask the patient to look straight ahead. (Note: it used to be common to ask the patients to look upward and inward and some ophthalmologists may still do this. However, this seems to put the needle path close to the

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optic nerve, ophthalmic artery and ophthalmic vein. Looking forward seems to be better.)

3. The injection is at the junction of the lateral and middle thirds of the inferior orbital rim.

4. Advance slowly. The needle should only penetrate retrobulbar fat and intermuscular septum. If you feel resistance, the needle may be in muscle, optic nerve or wall of the eye and it should be withdrawn and redirected.

5. Advance to 35 mm (depth of the needle).

6. Inject approximately 1cc of local anesthetic at this depth and then another 1cc of local anesthetic while withdrawing the needle.

CHOICE OF LOCAL ANESTHETIC:The most commonly used local anesthetic agents are a 1:1 mixture of 2% lidocaine with 0.5 or 0.75% bupivicaine. Some like to use epinephrine or hyaluronidase.

OOCULOCARDIAC REFLEXBradycardia, junctional rhythm, or asystole can occur secondary to traction on the eye and ocular muscles. This is called the oculocardiac reflex (OCR). Better knowledge and aggressive treatment has decreased serious morbidity from this reflex from 1 in 3,500 to less than 1 in 100,000.

Atropine of glycopyrrolate can be used to treat this reflex (some recommend that it be given prophylactically). OCR can occur in an empty orbit from extraocular muscle stimulation.

The afferent pathway is ciliary ganglion to ophthalmic division of trigeminal nerve to gasserian ganglion to main trigeminal sensory nucleus fourth ventricle. The efferent pathway is the vagus nerve.

Hypoxia, hypercarbia and light anesthesia potentiate this reflex and should be avoided. Retrobulbar block does not guarantee attenuation of this reflex, so use caution when massaging the eye after placing the block. (The eye is commonly massaged with light pressure after the local anesthetic is injected to promote onset and completeness of the block.

PERIBULBAR ANESTHESIA:Another technique that will produce orbital anesthesia has been described that involves injections above and below the orbit, with local anesthetic deposited in the orbicularis oculi muscle, behind it, and beneath, above and behind the globe. The potential for intraocular or intradural injection is decreased because the anesthetic is deposited outside the muscle cone. The risk of intraconal hemmorhage and direct optic nerve injury is also decreased.

COMPLICATIONS OF RETROBULBAR BLOCK:

Retrobulbar Hemmorhage: This is the most common complication seen and is due to inadvertant puncture of vessels within the retrobulbar space. It is evidenced by the simultaneous appearance of an excellent motor block of the globe, closing of the upper lid, proptosis and a palpable increase in intraocular pressure. Subconjunctival blood and eyelid ecchymosis may be seen as the hemmorhage extends anteriorly. Retrobulbar hemmorhage can lead to other complications such as central retinal artery occlusion and stimulation of the oculocardiac reflex. That said, many are minimal or even subclinical. On a rare occasion, surgery may be continued. However, it is usually considered the best course of action to postpone surgery for 2-4 days after hemmorhage because of the risk of repeat hemmorhage.

Oculocardiac Reflex: As discussed above. Note that this can occur several hours later in the event of an expanding hemmorhage. Thus, the patient should be closely monitored for several hours following a hemmorhage. If the OCR develops, surgical stimulation should stop and intravenous atropine is the treatment of choice (0.007 mg/kg).

Central Retinal Artery Occlusion: This can result from retrobulbar hemmorhage and may result in total loss of vision if not treated. If retrobulbar hemmorhage occurs, the patient's intraocular pressure and central retinal artery pulsations should be monitored. If external pressure on the globe is high enough to result in compression of the retinal arteries, then the surgeon will perform a deep lateral canthotomy or an anterior chamber paracentesis to decompress the orbit. This complication can also occur if the dura is penetrated and the local anesthetic is injected into the subarachnoid space.

Puncture of the Posterior Globe: Use of a blunted needle is common in an attempt to reduce this complication. However, this puncture can still occur and is more likely in patients with severely myopic eye ("long eye") or requiring repeated anesthetic injections. The patient experiences immediate ocular pain and restlessness following perforation. Intraocular hemmorhage and retinal detachment may occur.

Penetration of the Optic Nerve: Direct injury to the nerve, injection into the nerve sheath with compression ischemia and intramural sheath hemmorhage can result in optic atrophy and loss of vision even without retrobulbar hemmorhage. (See previous discussion concerning asking the patient to look forward during blockade)

Inadvertant Brain Stem Anesthesia: Accidental injection into the CSF can occur during the block due to perforation of the meningeal sheaths that surround the optic nerve. The patient may experience disorientation, amaurosis fugax, aphasia, hemiplegia, unconsciousness, convulsions, and respiratory or cardiac arrest. The incidence of this is estimated in studies to be 0.13%. Direct injection intravascularly via the optic nerve sheath or local anesthesia carried by the ophthalmic and internal carotid artery by retrograde flow to the thalamus and midbrain can also present the same way. This situation requires prompt recognition and treatment (including airway control, respiratory support, possible cardiac intervention, etc.)

Epinephrine Toxicity: In patients with hypertension, angina, or arryhthmias, the amount of epinephrine injected with the local anesthetic should be reduced. Injections of a total of 0.05 mg (10cc of 1:200,000) of epinephrine does not contribute significantly to problems in these patients. In fact, the release of endogenous catecholamines in reponse to suboptimal analgesia may greatly exceed the small amount of exogenous epinephrine administered.

Other Complications: Allergic reactions may occur to the ester-type local anesthetics. Blocks usually last 2 to 3 hours. If the block wears off before surgery is complete, supplementation of the retrobulbar block may be risky when the eyeball is open. The volume of injected fluid, edema, or hemmorhage may distort original anatomy and make surgery difficult.

CONTRAINDICATIONS TO RETROBULBAR BLOCK:

• Age less than 15 years old • Procedures lasting significantly more than 90 minutes • Uncontrolled cough, tremor or convulsive disorder • Disorientation or mental impairment • Excessive anxiety or claustrophobia • Language barrier or deafness • Bleeding or coagulation disorders (some surgeon will proceed

despite mild coagulopathy) • Perforated globe • Inability to lie flat