Anesthesia for Ophthalmic and Maxillofacial Surgery PDF

Anesthesia for ophthalmic and maxillofacial surgery For 4th year anesthesia students BY;Tiruzer.H 1 ophthalmic and maxillofacial anesthesia by tiruzer.h  Contents  Oc...

Anesthesia for ophthalmic and maxillofacial surgery For 4th year anesthesia students BY;Tiruzer.H 1 ophthalmic and maxillofacial anesthesia by tiruzer.h  Contents  Ocular anatomy and physiology  Open eye injury  IOP AND OCR  Ophthalmic drugs  Lefort classification  Anesthesia for ophthalmic and maxillofacial surgery ophthalmic and maxillofacial anesthesia by tiruzer.h 2  Objectives  Discuss the anatomy and physiology of the eye  Discuss IOP and OCR and their effect on anesthetic management  Describe the challenges of open eye injury and full stomach in anesthetic management  Describe the effects of ophthalmic drugs on anesthesia management  Assess and optimize Ophthalmic surgical patientsP  provide and manage anesthesia for various types of Ophthalmic surgical patients  Describe Leo fort’s classification and its implication for anesthesia management ophthalmic and maxillofacial anesthesia by tiruzer.h 3  Introduction Ophthalmic surgery poses unique problems, including  regulation of intraocular pressure control of intraocular gas expansion prevention of the oculo cardiac reflex and management of its consequences, and management of systemic effects of ophthalmic drugs ophthalmic drugs may significantly alter the reaction to anesthesia and  concomitantly, anesthetic drugs and maneuvers may dramatically influence intraocular dynamics. ophthalmic and maxillofacial anesthesia by tiruzer.h 4  Introduction  the anesthetist must have detailed knowledge of ocular anatomy, physiology, and pharmacology  Patients undergoing ophthalmic surgery may represent extremes of age and coexisting medical diseases  most ophthalmic procedures are performed under topical or regional anesthesia.  The anesthesia practitioner must be familiar with their potential complications, including those of the accompanying sedation ophthalmic and maxillofacial anesthesia by tiruzer.h 5  Cont…  There are numerous surgical procedures that are unique to the specialty of ophthalmology.  They can be classified as extraocular or intraocular.  This distinction is critical because anesthetic considerations are different for these two major surgical categories.  For example, with intraocular procedures, profound akinesia (relaxation of recti muscles) and meticulous control of intraocular pressure (IOP) are requisite.  However, with extraocular surgery, the significance of IOP fades, whereas concern about elicitation of the oculocardiac reflex assumes prominence. ophthalmic and maxillofacial anesthesia by tiruzer.h 6  Requirements of ophthalmic Surgery  Safety  Akinesia  Analgesia  Minimal bleeding  Avoidance or obtundation of oculo cardiac reflex  Control of intraocular presuue  Awareness of drug interactions  Smooth emergence ophthalmic and maxillofacial anesthesia by tiruzer.h 7  Ocular anatomy ophthalmic and maxillofacial anesthesia by tiruzer.h 8 Cont… subdivisions of ocular anatomy include the Orbit the eye itself  the extraocular muscles the eyelids  and the lacrimal system. ophthalmic and maxillofacial anesthesia by tiruzer.h 9  Orbit  The orbit is a bony box, or pyramidal cavity, housing the eyeball and its associated structures in the skull.  Composed of frontal, zygomatic, greater wing of the sphenoid, maxilla, palatine, lacrimal, and ethmoid.  Knowing the surface relationship enable for the performance of regional bock ophthalmic and maxillofacial anesthesia by tiruzer.h 10  Coat of the eye  The wall of the globe has three layers: i. Sclera; extrinsic eye muscle attach to this layer. ii. Uveal tract iii. Retina Outer layer which covers and protects the exposed portion of the eye ball and the inner eyelid is conjuctiva ophthalmic and maxillofacial anesthesia by tiruzer.h 11  Sclera  The fibrous outer layer, or sclera, is protective, providing sufficient rigidity to maintain the shape of the eye  Forms the posterior portion of the eye ball  The transparent cornea is the anterior most part of the sclera.  Most of the focus power of the eye is from the curvature of the cornea.  Both sclera& cornea serve to protect the retina ophthalmic and maxillofacial anesthesia by tiruzer.h 12  Uveal tract  Has three structures: A. Choroid; a layer of blood vessels located posteriorly. Pigmented layer, thin& dark B. Iris; The pigmented iris controls light entry with muscle fibers that change the size of the pupil - Pupil: determine how much light lets into the eye.: C.Ciliary body; It produces aqueous humor ophthalmic and maxillofacial anesthesia by tiruzer.h 13  Retina  The retina is a neurosensory membrane composed of ten layers that convert light impulses into neural impulses  Light stimulates retinal photoreceptors to produce neural signals that the optic nerve carries to the brain.  There are no capillaries in the retina.  Retinal detachment from the choroid layer ???  The retinal layer ends approximately 4mm behind the iris. ophthalmic and maxillofacial anesthesia by tiruzer.h 14  Eye  Located at the orbital apex, transmits the optic nerve and the ophthalmic artery as well as the sympathetic nerves from the carotid plexus.  A sphere about 24 mm in diameter and organ of vision  The center of the eye is filled with vitreous gel.  This thick fluid has attachments to blood vessels and the optic nerve ophthalmic and maxillofacial anesthesia by tiruzer.h 15  CORNEA  The outer most layer, allows light to enter the eye.  No blood vessel but have nerve endings. Conjunctiva  A clear mucous membrane which covers the surface of the globe  Transparent  Popular site for administration of ophthalmic drugs  Protects the cornea and eye from infection  Lubrication ophthalmic and maxillofacial anesthesia by tiruzer.h 16  Lens  Transparent, flexible tissue located behind the iris and pupil  Second part of eye after cornea that helps to focus light and images on retina  Cililary muscles are attached to the lens & contract or release to change the lens shape and curvature ophthalmic and maxillofacial anesthesia by tiruzer.h 17  Extraocular muscles The six extraocular muscles lie within a cone behind the eye surrounding the optic nerve The superior and inferior rectus  Contract reciprocally  Controls downward and upward movement of the eye, respectively ophthalmic and maxillofacial anesthesia by tiruzer.h 18 Cont..  The median and lateral rectus - Contract reciprocally -Control side to side movement of the eye respectively  The superior and inferior oblique muscle -Which control rotation of the eye ball -Keeps visual field in up right position ophthalmic and maxillofacial anesthesia by tiruzer.h 19  Lacrimal gland  The bilobed lacrimal gland provides most of the tear film, which serves to maintain a moist anterior surface on the globe  The lacrimal gland sits in the superior temporal orbit.  It releases tears across the surface of the globe.  Tears drain via the puncta near the medial canthus of the eyelids.  Tears flow through the canaliculi to the lacrimal sac and duct, to drain into the nasopharynx. ophthalmic and maxillofacial anesthesia by tiruzer.h 20  Blood supply  The ophthalmic artery provides most of the blood supply to the orbital structures.  It is a branch of the internal carotid artery, close to the circle of Willis.  The superior and inferior ophthalmic veins drain directly into the cavernous sinus. ophthalmic and maxillofacial anesthesia by tiruzer.h 21  Innervation  Cranial nerves (CN) innervate the ocular structures.  The optic nerve (CN II) carries the neural signals from the retina ophthalmic and maxillofacial anesthesia by tiruzer.h 22  Motor innervations  Occulomotor nerve (CN III)  Medial, superior, inferior rectus an inferior oblique muscles.  Trochlear nerve (CN IV)  Superior oblique muscle  Abducens nerve (CN VI)  Lateral rectus muscle Zygomatic branches of facial nerve  Orbicularis oculi muscle ophthalmic and maxillofacial anesthesia by tiruzer.h 23  Sensory innervations  By the trigeminal nerve which has 3 branches Ophthalmic - give innervations to globe - Frontal - Lacrimal - Nasociliary: Sends sensory fibers to the medial canthus, lacrimal sac, and ciliary ganglion(sensory innervation to the cornea, iris, and ciliary body) ophthalmic and maxillofacial anesthesia by tiruzer.h 24 Cont…  Parasympathetic fibers originate from the oculomotor nerve (CN III) and synapse in the ciliary ganglion before supplying the iris sphincter muscle.  Sympathetic fibers originate from the carotid plexus and travel through the ciliary ganglion to innervate the dilator muscle of the iris.  The ciliary ganglion provides sensory innervation to the cornea, iris, and ciliary body. ophthalmic and maxillofacial anesthesia by tiruzer.h 25  Ocular physiology  The eye is a complex organ, concerned with many intricate physiologic processes.  The formation and drainage of aqueous humor and their influence on IOP in both normal and glaucomatous eyes are among the most important function  An appreciation of the effects of various anesthetic manipulations on IOP requires an understanding of the fundamental principles of ocular physiology. ophthalmic and maxillofacial anesthesia by tiruzer.h 26  Fluid system of the eye o Maintains sufficient pressure in the eye ball to keep it remain distended o 2 major types of fluids in the eye: VH & AH Vitreous humor  Clear gelatinous substance which fills the vitreous cavity  Helps the eye hold its shape and occupies the posterior compartment of the eye  It does not undergo regular formation drainage ophthalmic and maxillofacial anesthesia by tiruzer.h 27  Aqueous humor  Transparent watery fluid similar to plasma, but low protein concentration  Is secreted from the cilliary epithelium  It fills both the anterior and the posterior chambers of the eye  Its volume is about 250 μL and is produced at a rate of 2.5μL/ min(undergo regular formation and drainage)  Maintains IOP and inflates the globe of the eye  Provide nutrition to avascular ocular tissue ophthalmic and maxillofacial anesthesia by tiruzer.h 28 Formation and Drainage of Aqueous Humor(AH) Active formation  2/3 is formed in the posterior chamber by the ciliary body involving both the carbonic anhydrase and the cytochrome oxidase systems Passive filtration  1/3 is formed by passive filtration of AH from the vessels on the anterior surface of the iris ophthalmic and maxillofacial anesthesia by tiruzer.h 29  CONT…  At the ciliary epithelium Sodium is actively transported into the posterior chamber HCO3- and Cl- passively follow the Na+ This active mechanism results in the osmotic pressure of the aqueous humor being many times greater than that of plasma.  AH flows from the posterior chamber through the pupillary aperture and into the anterior chamber, where it mixes with the aqueous formed by the iris  Bathes the avascular lens and the corneal endothelium ophthalmic and maxillofacial anesthesia by tiruzer.h 30 Cont…  Then the AH flows into the peripheral segment of the anterior chamber and exits the eye through the trabecular network, Schlemm canal, and episcleral venous system  A network of connecting venous channels eventually leads to the superior vena cava and the right atrium  Thus, obstruction of venous return at any point from the eye to the right side of the heart impedes aqueous drainage, elevating IOP accordingly. ophthalmic and maxillofacial anesthesia by tiruzer.h 31 Intraocular pressure  IOP is the fluid pressure inside the eye  Helps to maintain the shape of the eye  Mainly determined by the production and re absorption of AH  Normal 10 - 20 mm Hg  Considered abnormal > 22 mmHg  IOP is measured with a tonometer ophthalmic and maxillofacial anesthesia by tiruzer.h 32  Cont…  The globe is a relatively noncompliant compartment.  The volume of the internal structures is fixed except for aqueous fluid and choroidal blood volume.  The quantity of these two factors regulates IOP. ophthalmic and maxillofacial anesthesia by tiruzer.h 33  Three main factors that influence IOP  (1) external pressure on the eye  (2) scleral rigidity  (3) changes in intraocular contents that are semisolid (lens, vitreous, or intraocular tumor) or fluid (blood and aqueous humor).  Although these factors are significant in affecting IOP, the major control of intraocular tension is exerted by the fluid content, especially the aqueous humor ophthalmic and maxillofacial anesthesia by tiruzer.h 34 Factors that ↑ IOP  External pressure  Diurnal variation  Changes in IO contents that are semisolid  Positioning: trendelenburg position which causes venous congestion  Elevated in ABP  Elevated PaCO2 (hypercarbia)  Laryngoscopy and intubation ophthalmic and maxillofacial anesthesia by tiruzer.h 35 Cont..  Raised venous pressure  Coughing, straining, vomiting and  Compressed neck veins  ↓ing aqueous drainage and ↑ing choroidal BV  Scch  ↑ IOP via prolonged contracture of the EOMs during the fasciculation.  Unlike other skeletal muscle, EOMs contain cells with multiple NMJ  Repeated depolarization of these cells by sux causes the prolonged contracture ophthalmic and maxillofacial anesthesia by tiruzer.h 36  Factors that ↓IOP  IV induction agents except ketamine  Inhalational Induction agents  Non-depolarizing muscle relaxants  Reduction in AH volume - e.g. acetazolamide ↓ IOP by inhibiting production of AH  Reduction in vitreous volume- e.g. mannitol which exerts its effect as an osmotic diuretics  Acetazolamide and carbonic anhydrase inhibitors ophthalmic and maxillofacial anesthesia by tiruzer.h 37 Cont…  ↓ in venous pressure  head up tilt by at least 15 degree  Mild Hypotension  SBP< 90mmHg ↓ IOP, but a significant ↓ in BP should be avoided  ↓ in PaCO2 (Hypocarbia)  Acts by constricting the choroid vessels ophthalmic and maxillofacial anesthesia by tiruzer.h 38 The effect of cardiac and respiratory variables on intraocular pressure (IOP) ophthalmic and maxillofacial anesthesia by tiruzer.h 39 The effect of anesthetic agents on IOP  Intravenous anesthetics  These drugs decrease intraocular pressure  Exception is ketamine, It usually ↑ ABP and does not relax extraocular muscles, thus, ↑ IOP  Etomidate  Etomidate induced myoclonus ↑ IOP in ruptured globe. ophthalmic and maxillofacial anesthesia by tiruzer.h 40 Inhaled anesthetics  Inhalational anesthetics decrease intraocular pressure in proportion the depth of anesthesia.  The decrease has multiple causes: 1. A drop in blood pressure reduces choroidal voume 2. relaxation of the extraocular muscles lowers wall tension 3. pupillary constriction facilitates aqueous outflow. ophthalmic and maxillofacial anesthesia by tiruzer.h 41 Muscle relaxants  Succinylcholine increases intraocular pressure by 5—10 mm Hg for 5—10 minutes principally through prolonged contracture of the extraocular muscles.  Nondepolarizing muscle relaxants do not increase intraocular pressure. ophthalmic and maxillofacial anesthesia by tiruzer.h 42  The effect of anesthetic agents on intraocular pressure (lOP) ophthalmic and maxillofacial anesthesia by tiruzer.h 43  Glaucoma  Glaucoma is a condition characterized by elevated IOP, resulting in impairment of capillary blood flow to the optic nerve with eventual loss of optic nerve tissue and function.  Two different anatomic types of glaucoma exist: open-angle or chronic simple glaucoma, and closed-angle or acute glaucoma  Common cause of blindness  IOP ↑ as high as 60 to 70 mmHg.  Increased IOP = causes compression of the axon of optic nerve at optic disk. ophthalmic and maxillofacial anesthesia by tiruzer.h 44 Glaucoma causes - Blockage of axonal flow of cytoplasm from neuronal cell bodies into the retina to the peripheral nerve fibers entering the brain. (Luck of nutrient) - Compression of retinal arteries (reduces nutrition to retina) ophthalmic and maxillofacial anesthesia by tiruzer.h 45 The most common cause of glaucoma * Increased resistance to out flow of AH fluid from trabecular spaces into ( canal of shelemm at irido corneal junction a) Acute eye inflammation (WBC tissue debris) can block and cause acute increase in IOP b) In older age fibrous occlusion of trabecular spaces ophthalmic and maxillofacial anesthesia by tiruzer.h 46 Type of glaucoma  Open angle glaucoma  Closed angle glaucoma ophthalmic and maxillofacial anesthesia by tiruzer.h 47 Open eye injury  It is defined as penetration of the eye by sharp or projectile object and high velocity objects.  Commonly involves cornea and corneo-scleral junction  most common in children at play with sharp objects and adult males greater than women. ophthalmic and maxillofacial anesthesia by tiruzer.h 48  Etiology and risk factors for open eye injury  Sharp or high velocity object such as , sticks, knives, scissors, nails.  Male gender  Failure to wear adequate eye protection while performing high risk activities such as baseball, basketball  Substance abuse including alcohol and marijuana  Motor vichle collision ophthalmic and maxillofacial anesthesia by tiruzer.h 49 Signs and symptoms  Subconjunctival hemorrhage  Shallow or flat anterior chamber  Hyphema(blood in the anterior chamber)  Hypopyon (pus in the anterior chamber)  Iris deformities  Lens disruption ophthalmic and maxillofacial anesthesia by tiruzer.h 50 Cont…  Posterior segment findings such as vitreous hemorrhage, retinal tears, retinal hemorrhage  Visible foreign body  Pain or double vision  Corneal tear ophthalmic and maxillofacial anesthesia by tiruzer.h 51  Prevention of open eye injury  Appropriate and adequate eye protection when performing visually threatening activities  Supervise children carefully and teach them how can play with out injury.  Always wear protective eye goggle when using power tools , hammer or other striking tools and participating in sports ophthalmic and maxillofacial anesthesia by tiruzer.h 52  General treatment  Evaluated and treated immediately.  The treatment is mostly surgical intervention  If surgical exploration is planned, o A fox shield o Antiemetics o Systemic iv antibiotics: ciprofloxacilin 5oomg po BID for 7 day o Or, chloramphenicol 500mg QID, o update of tetanus status should be completed ophthalmic and maxillofacial anesthesia by tiruzer.h 53  Associated injuries  The location of the eye within the bony orbit results in frequent associated injuries to the head and neck.  These other injuries include :  Traum atic brain injuries: opened and closed,  cervical spine trauma with and without neurologic compromise. ophthalmic and maxillofacial anesthesia by tiruzer.h 54  Preoperative Evaluation  Aim: help identify the timing of the injury and mechanism The time of last oral intake before or after the injury should be established.  Consider a full stomach if the injury occurred within 8 h after the last meal, even if the patient did not eat for several hours after the injury Because gastric emptying is delayed by pain and anxiety. ophthalmic and maxillofacial anesthesia by tiruzer.h 55 Cont…  Any injuries other than the eye should be ascertained. Questions such as o What was the patient doing during the injury o What potential objects causing the injury are important prior to physical evaluation.  Appropriate medical history including current medications, allergies, tetanus status should be asked and reviewed. ophthalmic and maxillofacial anesthesia by tiruzer.h 56 Physical examination Ophthalmic examination after severe trauma can be difficult. Obtaining a visual acuity and pupillary examination most important.  Careful handling of the eye to prevent any pressure on the globe  If penetrating injury to the globe, examination will be limited so the globe can be shielded to prevent extrusion of intraocular contents. ophthalmic and maxillofacial anesthesia by tiruzer.h 57 Cont…  Avoid transdermal scopolamine: blur vision and confuse ophthalmologic dx and evaluation.  Life threatening problems should be dealt immediately. Pts with other disease such as DM or IHD should be optimized prior to surgery if the time allows. ophthalmic and maxillofacial anesthesia by tiruzer.h 58 Major considerations and concerns of open eye injury These patients are considered as full stomach, so precautions have to be taken to prevent complications of full stomach. Aspiration of stomach contents can cause lung injury and pneumonia.  Strategies to prevent aspiration pneumonia. o Premedication with Metoclopramide Histamine H2-receptor antagonists Non-particulate antacids ophthalmic and maxillofacial anesthesia by tiruzer.h 59 Cont… o Evacuation of gastric contents-N G tube o RSI - Cricoid pressure o A rapid-acting induction agent-Sux, rocuronium, or rapacuronium o Avoidance of excessive PPV o Intubation as soon as possible ophthalmic and maxillofacial anesthesia by tiruzer.h 60 Cont… precautions have to taken to prevent ↑ in IOP  Laryngoscopy, ETTI, bucking, coughing and sux, ketamine. Thus, care has to taken during laryngoscopy and during selection of drugs. Do not force eyelids open - pressure on the lids may cause extrusion of ocular contents. Do not attempt to remove a protruding FB from the globe. ophthalmic and maxillofacial anesthesia by tiruzer.h 61 Anesthetic considerations and management of open eye injury  Preoperative Preparation and premedication  goal : to minimize the risk of aspiration by ↓ gastric volume and acidity  to prevention significant ↑ in IOP ophthalmic and maxillofacial anesthesia by tiruzer.h 62 Cont… Aspiration is prevented by proper selection of drugs and anesthetic techniques. Evacuation of gastric contents with a NGT may lead to coughing, retching, that ↑ IOP If possible, metoclopramide IV (10 mg) as soon as possible and repeated every 2–4 h until surgery ophthalmic and maxillofacial anesthesia by tiruzer.h 63 Cont… Ranitidine (50 mg IV), cimetidine (300 mg I V), and famotidine (20 mg IV)  antacids have an immediate effect.  Non-particulate antacids ( sodium citrate, potassium citrate and citric acid) should be given immediately prior to induction (15– 30 mL orally). Do not use opioids as premedication ophthalmic and maxillofacial anesthesia by tiruzer.h 64 Choice of anesthetic technique The choice of technique will depend upon factors including: whether the pt. is able to lie flat  Protect his or her own airway safely for the duration of the procedure The advantage of GA in full stomach cases. ophthalmic and maxillofacial anesthesia by tiruzer.h 65 Cont… Local anesthesia has its own problems:  Spread of the local anesthetic is poor A injection of local anesthetics RBB is associated with ↑ in IOP which may lead to vitreous loss. Ocular compression after the block is also not an option if the patient has an open eye injury Thus, RA should best be avoided and it is C/I. ophthalmic and maxillofacial anesthesia by tiruzer.h 66 Cont… Advantage of GA Protect the airway safely for the duration of the procedure Common in children and uncooperative Minimize risk of ↑ in IOP Thus, children, uncooperative or intoxicated patients usually are the better candidates for GA. ophthalmic and maxillofacial anesthesia by tiruzer.h 67  Induction o The anesthetic choose must balance risk of blindness and aspiration. o Metoclopramide (0.15 mg/ kg IV) o Use of anti-cholinergic is useful for preventing the oculocardiac reflex. o Pretreatment with IV lidocaine(1.5mg/kg),to blunt the cardiovascular and IOP responses to laryngoscopy and tracheal intubation and remifentanil (0.7 microgram/kg IV), 3 to 5 minutes before induction. ophthalmic and maxillofacial anesthesia by tiruzer.h 68 Cont… o Atenolol (0.1 mg/kg IV) or labetalol (0.03 mg/kg IV) block the cardiovascular response to tracheal intubation, especially in patients with angina or hypertension. o Preoxygenation (avoid pressure on the eye by face mask). o Pre- oxygenation for 3-4 minutes with the patient holding the mask can build confidence and relive anxiety o RSI and cricoid pressure ophthalmic and maxillofacial anesthesia by tiruzer.h 69 Cont… Use of SCCH(controversial) despite Rapid onset of relaxation Smooth intubating conditions Short duration of action Induction agents all except ketamine and etomidate Analgesics like fentanyl(2-3microgram/Kg),remifentanyl(0.7micro gram/Kg Avoid awake intubation as it causes expulsion of the eye contents by increasing IOP ophthalmic and maxillofacial anesthesia by tiruzer.h 70 Induction summary  Aspiration prophylaxis if not given preoperatively preoygenation  IV lidocaine(1-1.5 mg/kg  fentanyl (2-3microgram/kg )  labetolol (5-10 mg )or atenolol (0.1 mg/kg IV)  defasiculating ( priming) dose of NDMR thiopentone(3-6mg/kg)/propofol (2.5 mg/kg)RSI and maintain cricoid pressure intubating dose of sux(controversial)or NDMR  Always GA ophthalmic and maxillofacial anesthesia by tiruzer.h 71  Maintenance and intra operative management  Adequate depth of anesthesia to avoid movement or coughing.  Document neuromuscular blockade with a train-of-four response to prevent coughing caused by accidental carinal stimulation.  A good monitoring of vital signs.  Controlled ventilation with normal ETCo2.  ECG  A little head up tilt. ophthalmic and maxillofacial anesthesia by tiruzer.h 72 Special Considerations during Extubation and Emergence  Smooth emergence  Aided by administering an antiemetics 30 minutes before the end of operation or during surgery and by lidocaine or remifentanil (0.5 mg/ kg IV) 5 minutes before the patient awakens.  Patients at risk for aspiration during induction are also at risk during extubation and emergence. ophthalmic and maxillofacial anesthesia by tiruzer.h 73 Cont… Therefore, extubation must be delayed until the patient is awake and has intact airway reflexes.  Deep extubation increases the risk for vomiting and aspiration. Therefore, the trachea should be extubated while the patient is awake, breathing spontaneously, and receiving oxygen in the lateral position as well as the patient‘s head is to the side ophthalmic and maxillofacial anesthesia by tiruzer.h 74  Special care in children o Special care is needed in the children having open eye injury.  Avoid narcotics if associated head injury.  crying, rubbing of the eyes, anxiety should be avoided.  They should be nicely sedated in the preoperative period; but avoid hypoxia.  Close and special monitoring in the post anesthesia care unit. ophthalmic and maxillofacial anesthesia by tiruzer.h 75 Cont…  Analgesic along with anti-emetic.  The iv access should be made gently by topical application of anaesthetic cream or gentle induction of anaesthesia by mask (with 7 to 8 % of sevoflurane) with good pre-oxygenation. ophthalmic and maxillofacial anesthesia by tiruzer.h 76 Cont…  Avoid Pain in the pop period  Analgesia : paracetamol/codeine and oral/ rectal diclofenac.  Close monitoring in the PACU is essential  Minimize PONV. Thus, prescribe antiemetics in POP period. ophthalmic and maxillofacial anesthesia by tiruzer.h 77 Conclusion. Aspiration prophylaxis Give 1.5mg/kg intravenous lidocaine Induction: thiopentone or propofol, NDMRs,fentanyl or remifentanyl and RSI RA is C/I Avoid awake intubation Avoid external pressure on the eye globe during preoxygenation ophthalmic and maxillofacial anesthesia by tiruzer.h 78 Cont… Weigh the risk of aspiration against the risk of blindness Pretreatment with NDMRs before Scch(controversy) Avoid ketamine and etomidate. Smooth emergence Extubate at left lateral when fully awake Avoid PONV Good POP pain management ophthalmic and maxillofacial anesthesia by tiruzer.h 79  SYSTEMIC EFFECTS OF OPHTHALMIC DRUGS  There is considerable potential for drug interactions during administration of anesthesia for ocular surgery.  Topical ophthalmic drugs may produce undesirable systemic effects or may have deleterious anesthetic implications  Topical ophthalmic drugs can be absorbed through the conjunctiva, or they drain through the nasolacrimal duct and can be absorbed through the nasal mucosa.  Usage of topical medications can have implications for the anestetist. ophthalmic and maxillofacial anesthesia by tiruzer.h 80 Atropine  Used to produce mydriasis and cyclopiegia.  The 1% solution contains 0.2 to 0.5 mg of atropine per drop.  Systemic reactions, include tachycardia, flushing, thirst, dry skin, and agitation.  Atropine is contraindicated in closed-angle glaucoma. ophthalmic and maxillofacial anesthesia by tiruzer.h 81  Scopolamine  One drop of the 0.5% solution has 0.2 mg of scopolamine.  CNS excitement can be treated with physostigmine, 0.015 mg/kg IV, repeated one or two times in a 15- minute period.  It is contraindicated in closed-angle glaucoma ophthalmic and maxillofacial anesthesia by tiruzer.h 82  Phenylephrine Hydrochloride  Phenylephrine hydrochloride is used to produce capillary decongestion and pupillary dilatation.  Applied to the cornea, it can cause palpitations, nervousness, tachycardia, headache, nausea and vomiting, severe hypertension, reflex bradycardia, and subarachnoid hemorrhage.  Solutions of 2.5%, 5%, and 10% (6.25 mg phenylephrine per drop) are available. ophthalmic and maxillofacial anesthesia by tiruzer.h 83 Epinephrine  Topical 2% epinephrine will decrease aqueoua secretion, improve outflow, and lower intraocular pressure in open-angie glaucoma.  Side-effects include hypertensionsion, palpitations, fainting, pallor, and tachycardia.  The effects last about 15 minutes.  the arrhythmogenic effects are potentiated by halothane  One drop of 2% solution contains 0.5 to 1 mg of epinephrine. ophthalmic and maxillofacial anesthesia by tiruzer.h 84  Timolol Maleate (Tinwptic)  Timolol maleate is a beta-blocker used in the treatment of chronic glaucoma.  Side- effects include light-headedness, fatigue, disorientation, depressed CNS function, and exacerbation of asthma. Bradycardia, bronchospasm, and potentiation of systemic beta-blockers can occur.  timolol should be administered with caution to patients with known obstructive airway disease, congestive heart failure, or greater than first-degree heart block. ophthalmic and maxillofacial anesthesia by tiruzer.h 85  Acetylcholine  Acetylcholine can be injected intraoperatively into the anterior chamber to produce miosis.  Side-effects are due to its parasympathetic action they include hypotension, bradycardia, bronchospasm, increased salivation and bronchial secretions ophthalmic and maxillofacial anesthesia by tiruzer.h 86  Echothiophate Iodide (Phosplzolfne Iodide) A cholinesterase inhibitor, echothiophate iodide is used as a miotic agent.  prolong the effect of both succinyicholine and ester-type local anesthetics.  Levels of pseudocholinesterase decrease by 80% after 2 weeks on the drug.  Succinyicholine and ester-type local anesthetics should be avoided. ophthalmic and maxillofacial anesthesia by tiruzer.h 87 Systemic effects of ophthalmic drugs ophthalmic and maxillofacial anesthesia by tiruzer.h 88 Oculocardiac reflex The Oculocardiac Reflex (OCR) is manifested by  Braycardia  Bigeminy  Ectopic  Nodal rhthms  Atroventricular block  Cardiac arrest ophthalmic and maxillofacial anesthesia by tiruzer.h 89 OCR Caused By  Traction on the extraocular muscles (medial rectus)  Ocular manipulation  Manual pressure on the globe.  administration of a retrobulbar block, and trauma to the eye ophthalmic and maxillofacial anesthesia by tiruzer.h 90 The OCR is seen during  Eye muscle surgery  Detached retina repair  Enucleation ophthalmic and maxillofacial anesthesia by tiruzer.h 91 What are the afferent and efferent pathways of the oculocardiac reflex?  The oculocardiac reflex is trigeminovagal.  The afferent pathway is by way of the ciliary ganglion to the ophthalmic division of the trigeminal nerve, and through the gasserian ganglion to the main sensory nucleus in the fourth ventricle.  The efferent pathway is though the vagus nerve. ophthalmic and maxillofacial anesthesia by tiruzer.h 92 What factors contribute to the incidence of the oculocardiac reflex?  Preoperative anxiety  light general anesthesia  Hypoxia  Hypercarbia  Increased vagal tone owing to age ophthalmic and maxillofacial anesthesia by tiruzer.h 93 Cont…  Routine prophylaxis for the oculocardiac reflex is controversial, especially in adults.  Anticholinergic medication may prevent the oculocardiac reflex.  Intravenous atropine or glycopyrrolate given immediately before traction on extraocular muscles is more effective than intramuscular premedication administered preoperatively.  However, anticholinergic medication should be administered with caution to any patient who has or may have coronary artery disease ophthalmic and maxillofacial anesthesia by tiruzer.h 94 How do you diagnose and treat the oculocardiac reflex?  Monitor the electrocardiogram intraoperatively and during any eye manipulation  immediate notification of the surgeon and cessation of surgical stimulation until heart rate recovers;  Confirmation of adequate ventilation, oxygenation, and depth of anesthesia;  administration of intravenous atropine (10 mcg/kg) if bradycardia persists; and  in recalcitrant episodes, infiltration of the rectus muscles with local anesthetic. ophthalmic and maxillofacial anesthesia by tiruzer.h 95  Intraocular gas expansion  Gas bubble may be injected into the posterior chamber during vitreous surgery to flatten a detached retina and facilitate anatomically correct healing  Nitrous oxide administration is contraindicated in this circumstance 35 times more soluble than nitrogen in blood If the bubble expands after the globe is closed, intraocular pressure will rise  The air bubble is absorbed within 5 days by gradual diffusion ophthalmic and maxillofacial anesthesia by tiruzer.h 96 Cont…  Sulfur hexafluoride, an inert gas that is less soluble in blood than nitrogen, provides a longer duration (up to 10 days) than an air bubble.  Nitrous oxide should be discontinued at least 15 minutes prior to the injection of air or sulfur hexafluoride  Nitrous oxide should be avoided until the bubble is absorbed (5 days for air and 10 days for sulfur hexafluoride). ophthalmic and maxillofacial anesthesia by tiruzer.h 97 Cont… Intraocular surgeries  Profound akinesia (relaxation of recti muscles)  Meticulous control of intraocular pressure (IOP) Extraocular surgeries  Elicitation of the oculocardiac reflex  Coexisting illnesses  Drug interaction  Smooth induction and emergence ophthalmic and maxillofacial anesthesia by tiruzer.h 98 The choice of general versus regional anesthesia is made on  The duration of the surgery  The relative risks and benefits of each technique for the patient  patient preference Regional anesthesia for eye surgery includes  A retrobulbar block  Peribulbar block  A facial nerve block  Sub-Tenon block ophthalmic and maxillofacial anesthesia by tiruzer.h 99 Unique challenges to the anesthetist  Regulation of IOP  Prevention of the OCR  Management of OCR  Control of intraocular gas expansion  Possible systemic effect of ophthalmic drugs  Coexisting medical problems ophthalmic and maxillofacial anesthesia by tiruzer.h 100  Regional Anesthesia for Ophthalmic Surgery  Options for local anesthesia for eye surgery include  topical application of local anesthetic  or placement of a retrobulbar, peribulbar, or sub-Tenon (episcleral) block.  Each of these techniques is commonly combined with intravenous sedation.  Local anesthesia is preferred to general anesthesia for eye surgery because local anesthesia involves less physiological trespass and is less likely to be associated with postoperative nausea and vomiting. ophthalmic and maxillofacial anesthesia by tiruzer.h 101 Cont…  However, eye block procedures have potential complications and may not provide adequate ophthalmic akinesia or analgesia.  Some patients may be unable to lie perfectly still for the duration of the surgery.  For these reasons, the appropriate equipment and qualified personnel required to treat the complications of local anesthesia and induce general anesthesia must be readily available. ophthalmic and maxillofacial anesthesia by tiruzer.h 102  RETROBULBAR BLOCKADE  The technique described involves introducing a needle percutaneously from an infero-temporal point aiming at the apex of the orbit  A small volume of local anaesthetic is deposited in the extraocular muscle cone.  To prevent the contraction of the orbicularis oculi muscle, a facial nerve block is performed. ophthalmic and maxillofacial anesthesia by tiruzer.h 103 Technique of retrobulbar block:   Patient in supine position  Gaze supero-nasal  Instil 2 drops of local anaesthetic solution.  Swab eyelids and surrounding area with antiseptic.  Palpate the inferior orbital rim with the index finger.  Raise a skin weal at the junction of the lateral and inferior orbital margin.  Introduce the 35mm long needle through the weal and direct it along the orbital floor until the tip of the needle has passed the equator of the anesthesia ophthalmic and maxillofacial eye (approx. by tiruzer.h 15mm). 104 Cont…  Redirect the needle upwards and inwards, in the direction of the apex of the orbit. Penetrate the fascia of the muscle cone and aspirate and inject 2-5 ml.  Apply intermittent digital compression of the eye for 2-4 min.  Examine the eye for akinesia (i.e. check the movement of the eyeball).  There should be little or no movement of the anaesthetised eyeball.  If there is significant movement of the eye, make a supplementary injection alongside the rectus muscle that is active. ophthalmic and maxillofacial anesthesia by tiruzer.h 105 Cont…  Choice of local anesthetic varies, but lidocaine 2% or bupivacaine (or ropivacaine) 0.75% are common.  The addition of epinephrine may reduce bleeding and prolong the anesthesia. ophthalmic and maxillofacial anesthesia by tiruzer.h 106 Retrobulbar (intraconal) block and schematic representation of the intraorbital muscle cone. ophthalmic and maxillofacial anesthesia by tiruzer.h 107 Complications of retrobulbar block  Local complications: Retrobulbar haemorrhage Globe perforation Central retinal artery occlusion  Secondary to retrobulbar haemorrhage  Puncture of dura around optic nerve Optic nerve damage Periorbital ecchymoses ophthalmic and maxillofacial anesthesia by tiruzer.h 108 Systemic complications:  Subarachnoid injection of local anaesthetic.  Cranial nerve block  Respiratory arrest  Cardiac arrest Intravascular injection: grand mal seizure. Retro-bulbar block is still occasionally required but is much less frequentlyused than sub-tenon or peri-bulbar blocks. ophthalmic and maxillofacial anesthesia by tiruzer.h 109  PERIBULBAR BLOCKADE  In contrast to retrobulbar blockade, with the peribulbar blockade technique, the needle does not penetrate the cone formed by the extraocular muscles.  Advantages of peribulbar block Large volumes of local anaesthetics are placed outside the muscle cone.  They spread to the apex and all compartments of the eye. Provides good analgesia while reducing the risk of dangerous complications. Well accepted by the patient with very little discomfort during injection. Facial nerve block is not necessary. ophthalmic and maxillofacial anesthesia by tiruzer.h 110 Disadvantages of peribulbar block Onset slower than the retrobulbar block. Large volumes of local anaesthetic used can cause toxicity. Globe perforation is possible. Intraocular pressure may be raised by the volume of solution. ophthalmic and maxillofacial anesthesia by tiruzer.h 111  Technique of peribulbar block: Establish IV access and monitoring  Light sedation can be used if required  Instil topical local anaesthetic drops to conjunctiva  The patient should lie supine and look straight ahead  Palpate the inferior orbital rim to find groove at junction of medial two thirds and lateral one third  Just lateral to and 1mm above this point insert a 25G/25mm long needle, with syringe attached, slowly along the orbit floor until the hub of the needle reaches the plane of the iris ophthalmic and maxillofacial anesthesia by tiruzer.h 112 Cont….  Aspirate then inject 6-8 ml of local anaesthetic.  Check for tension in globe and stop injecting if this occurs Withdraw needle and inject small volume of local anaesthetic in orbicularis of lower lid  Sometimes a second injection is required. Using a similar needle, insert it on the nasal side medial to the caruncle and parallel to the medial orbital wall.  A further 4–5ml of solution is injected  Apply digital compression or a compression device to spread local anaesthetic and normalise intraocular pressure. ophthalmic and maxillofacial anesthesia by tiruzer.h 113 Peribulbar (extraconal) block and schematic representation of the intraorbital muscle cone. ophthalmic and maxillofacial anesthesia by tiruzer.h 114  Sub-Tenon (Episcleral) Block  This block is becoming more commonly used as a safer alternative to retro and peri-bulbar blocks  Tenon’s fascia surrounds the globe and extraocular muscles.  Local anesthetic injected beneath it into the episcleral space spreads circularly around the sclera and to the extraocular muscle sheaths  A special blunt curved cannula is used for a sub-Tenon block ophthalmic and maxillofacial anesthesia by tiruzer.h 115 Techniques of sub-Tenon block - Apply topical local anaesthetic drops to conjunctiva. - Retract lower lid. - Lift the conjunctiva in the infero-nasal quadrant, with forceps, 5-7mm from the limbus. - Make a small incision in the conjunctiva and dissect inferonasally in the plane between the sclera and Tenon’s capsule. (Tenon’s capsule is white and avascular unlike the sclera). - In this plane a blunt curved cannula (Southampton) is passed backwards beyond the equator of the eye and 3-5ml of local anaesthetic deposited. ophthalmic and maxillofacial anesthesia by tiruzer.h 116 Advantages of Sub–Tenon block Easy to perform Avoids complications of globe perforation, haemorrhage or optic nerve damage Technique of choice in anticoagulated patients ophthalmic and maxillofacial anesthesia by tiruzer.h 117  Disadvantages of Sub–Tenon block  Dose not give such complete anaesthesia as retro and peri-bulbar blocks and does not provide akinesia.  A mild anxiolytic premedication may be required.  Occasional conjunctival haemorrhage. This is easily treated with cautery ophthalmic and maxillofacial anesthesia by tiruzer.h 118 Cont…  Complications with sub-Tenon blocks are significantly less than with retrobulbar and peribulbar techniques.  Globe perforation, hemorrhage, cellulitis, permanent visual loss, and local anesthetic spread into cerebrospinal fluid have been reported. ophthalmic and maxillofacial anesthesia by tiruzer.h 119  FACIAL NERVE BLOCK  A facial nerve block prevents squinting of the eyelids during surgery and allows placement of a lid speculum.  The major complication of these blocks is subcutaneous hemorrhage.  Others include  vocal cord paralysis  laryngospasm dysphagia  respiratory distress. ophthalmic and maxillofacial anesthesia by tiruzer.h 120  TOPICAL ANESTHESIA OF THE EYE  Increasingly, the trend has been to use simple topical local anesthetic techniques for anterior chamber (eg, cataract) and glaucoma operations rather than local anesthetic injections.  A typical regimen for topical local anesthesia involves the application of 0.5% proparacaine (also known as proxymetacaine) local anesthetic drops, repeated at5-min intervals for five applications,  followed by the topical application of a local anesthetic gel (lidocaine plus 2% methyl-cellulose) with a cotton swab to the inferior and superior conjunctival sacs. ophthalmic and maxillofacial anesthesia by tiruzer.h 121 Cont.  Ophthalmic 0.5% tetracaine may also be utilized.  Topical anesthesia is not appropriate for posterior chamber surgery (eg, retinal detachment repair with a buckle),  and it works best for faster surgeons using a gentle surgical technique that does not require akinesia of the eye. ophthalmic and maxillofacial anesthesia by tiruzer.h 122  INTRAVENOUS SEDATION  Many techniques of intravenous sedation are available for eye surgery.  particular drug used is less important than the dose.  Deep sedation, though sometimes used during placement of ophthalmic nerve blocks, is almost never used intraoperatively  because of the risks of apnea, aspiration, and unintentional patient movement during surgery ophthalmic and maxillofacial anesthesia by tiruzer.h 123 Cont…  An intraoperative light sedation regimen that includes small doses of midazolam, with or without fentanyl or sufentanil, is recommended.  Doses vary considerably among patients but should be administered in small increments.  Patients may find the administration of eye blocks frightening and uncomfortable,  and many anesthesia providers will administer small, incremental doses of propofol to produce a brief state of unconsciousness during the regional block. ophthalmic and maxillofacial anesthesia by tiruzer.h 124 Cont…  Some will substitute a bolus of opioid (remifentanil 0.1–0.5 mcg/kg or alfentanil 375–500 mcg) to produce a brief period of intense analgesia during the eye block procedure  Administration of an antiemetic should be considered if an opioid is used. ophthalmic and maxillofacial anesthesia by tiruzer.h 125 Postoperative Ocular Complications  Corneal Abrasion  Chemical Injury  Mild Visual Symptoms  Hemorrhagic Retinopathy  Retinal Ischemia  Acute Glaucoma ophthalmic and maxillofacial anesthesia by tiruzer.h 126  summary Inhalation anesthetics cause dose-related reductions in intraocular pressure (IOP). The oculocardiac reflex is triggered by pressure on the globe and by traction on the extraocular muscles, as well as on the conjunctiva or on the orbital structures. Ophthalmic drugs may significantly alter the patient's reaction to anesthesia. Similarly, anesthetic drugs and maneuvers may dramatically influence intraocular dynamics. ophthalmic and maxillofacial anesthesia by tiruzer.h 127  summary Several anesthetic options are available for many types of ocular procedures, including general anesthesia, retrobulbar block, peribulbar anesthesia, sub-Tenon (episcleral) block, topical analgesia The complications of ophthalmic anesthesia can be both vision- and life-threatening. With intraocular procedures, profound akinesia and meticulous control of IOP are requisite. However, with extraocular surgery, the significance of IOP fades, whereas concern about elicitation of the oculocardiac reflex assumes prominence. ophthalmic and maxillofacial anesthesia by tiruzer.h 128 Anesthesia for Maxillofacial reconstructive surgery  Maxillofacial reconstruction is often required to correct:  The effects of trauma (Le Fort fracture)  Developmental malformations  For radical cancer surgery ( maxillectomy or mandibulectomy) ophthalmic and maxillofacial anesthesia by tiruzer.h 129 Challenges of Maxillofacial reconstructive surgery  Traumatic disruption of the bony, cartilaginous, and soft-tissue components of the face and upper airway challenges provides a sort of challenges for anesthetist. 1) Failure to recognize the nature and extent of the injury and consequent anatomic alteration, 2) Unable to create appropriate plan for securing the airway safely 3 )Difficulty to implement the plan without doing further damage ophthalmic and maxillofacial anesthesia by tiruzer.h 130 Cont… 4) Difficulty to maintain the airway during the administration of an anesthetic 5) determine when and how to extubate the patient's trachea. 6) Failure to create a comfortable environment for both surgeon and anesthesiologist in a limited work space. ophthalmic and maxillofacial anesthesia by tiruzer.h 131  Preoperative considerations  Facial trauma can be associated with airway problems and massive hemorrhage as well patients may have other injuries i.e head injury  Unless there is acute airway compromise or massive hemorrhage, surgery for facial fractures is often delayed till other injuries have been treated and swelling subside.  Facial fracture occurs along lines of weakness of facial bones and are classified according to anatomy and displacement eg mandibular, midface, orbital ophthalmic and maxillofacial anesthesia by tiruzer.h 132 Cont…  35% mandibular fracture occurs at the condylar neck and may result in air way obstruction Because of posterior displacement of the anterior insertion of the tongue in bilateral mandibular fractures.  Extensive soft-tissue injury does not necessarily indicate bony trauma, and Conversely, serious fractures may exist with relatively little soft-tissue disruption ophthalmic and maxillofacial anesthesia by tiruzer.h 133 Cont… Particular attention should be focused on: o Jaw opening o Mask fit o Neck mobility o Maxillary protrusion(over bite) o Dental pathology o Nasal patency and debries. ophthalmic and maxillofacial anesthesia by tiruzer.h 134 Cont…  The air way should be secured before GA, if mask ventilation and ETI anticipated difficult.  Alternative method: Fibro optic nasal/oral intubation, or Tracheostomy with local anesthesia. ophthalmic and maxillofacial anesthesia by tiruzer.h 135 Cont…  Nasal intubation should be considered with caution in LeFort II and III fracture Because of the possibility of basilar skull fracture. If CSF leakage: avoid nasal intubation farther damage and brain tissue infection(meningitis) ophthalmic and maxillofacial anesthesia by tiruzer.h 136  Cont…  In 1901, Rene LeFort of Lille, attempted to determine if there is a reliable means of detecting facial fractures by examining: Facial soft-tissue injuries and by using the nature and extent of these injuries as indicators of bony disruption  LeFort determined the common lines of midface fracture, which are called: LeFort I, LeFort II and LeFort IIIfractures. ophthalmic and maxillofacial anesthesia by tiruzer.h 137  LeFort Classification of Fractures  Le Fort I fractures - unilateral or bilateral and pass transversely through the maxilla,  posterior displacement of the inferior portion of the maxilla may obstruct the nasopharynx.  Le Fort II fractures -usually bilateral and extend in a pyramidal fashion to include the maxilla, orbital floor, nasal bridge and lacrimal bones.  Le Fort III fractures- result in craniofacial dissociation, extending posteriorly from the bridge of the nose to the orbit and the zygomatic arch. ophthalmic and maxillofacial anesthesia by tiruzer.h 138  Classification  Le Fort II and III fractures are associated with cribriform plate fracture resulting in Dural tears and CSF leakage.  CSF leak often resolves with fracture fixation.  Persistent CSF leak needs lumbar CSF drainage or neurosurgical repair. ophthalmic and maxillofacial anesthesia by tiruzer.h 139 Diagrammatic representation of Le Fort I, II, and III fractures. Le Fort II and III fractures may coexist with a basilar skull fracture, a contraindication to nasal intubation. ophthalmic and maxillofacial anesthesia by tiruzer.h 140 ophthalmic and maxillofacial anesthesia by tiruzer.h 141 TECHNIQUE FOR GENERAL ANAESTHESIA IN DENTAL SURGERY (endotracheal intubation)  Pre-operative management  NPO  Assess the patient  observe nostrils for purulent discharge or deviated septum. Check for history of epistaxis and if so from which nostril  Give premedication: a benzodiazepine or small dose of opiate and atropine but avoid heavy sedation. ophthalmic and maxillofacial anesthesia by tiruzer.h 142 Intra operative management  Check with the surgeon if a nasal tube is required  Check the tube type and size  An oral tube of the right size.  Magill forceps.  A pharyngeal pack, moistened with water and wrung out.  Never use multiple swabs knotted together. ophthalmic and maxillofacial anesthesia by tiruzer.h 143 Cont…  General principles  The procedure is lengthy and associated with substantial blood loss  Placement of an oropharyngeal pack around the endotracheal tube.  Pack must be removed before extubation as it can lead to catastrophic airway obstruction if left. ophthalmic and maxillofacial anesthesia by tiruzer.h 144 Cont…  Suctioning of the stomach at the conclusion of surgery may attenuate postoperative retching and vomiting.  Profound vasoconstriction is required, Cocaine packs, local anesthetics, and epinephrine infiltration are often used simultaneously.  Interaction of inhalation anesthetics and epinephrine also be considered.  Great care for cardiac irritability like tachycardia and hypertension from epinephrine and cocaine ophthalmic and maxillofacial anesthesia by tiruzer.h 145  Cont…  The simultaneous use of these medications cause often dangerous side effects in elderly.  A moderate degree of controlled hypotension combined with head elevation decreases bleeding in the surgical site  Stabilize the head with a head ring and for operations on the roof of the mouth use a cloth or sand under the shoulder to extend the neck. ophthalmic and maxillofacial anesthesia by tiruzer.h 146  Care of throat pack  Tie or tape the pack to ETT place identification sticker on ETT or patients forehead to remember  Include the pack on the scrubs count. Laryngoscope should always be performed at the end of the procedure to clear any debris and ensure that packs are removed ophthalmic and maxillofacial anesthesia by tiruzer.h 147  Potential anesthetic problems  Airway contamination. The airway is always in danger of being contaminated, by irrigation fluid, secretions, dental material, teeth, blood etc. Protect it by: Using an endotracheal tube, either nasal or oral Using a pharyngeal pack Encouraging reflexes to return rapidly post-operatively Placing the patient in the tonsillar position post-operatively Not using local anaesthesia in the respiratory tract Not using excessive premedication. ophthalmic and maxillofacial anesthesia by tiruzer.h 148  Airway obstruction.  Shared airway  Nasal intubation  The pharyngeal pack needs absolutely meticulous attention  Forgetting to remove the pack can be FATAL ophthalmic and maxillofacial anesthesia by tiruzer.h 149 Further Evaluation  Indirect or Fiberoptic Laryngoscopy  X ray: Chest , Cervical Spine  CT or MRI  Flow- Volume Loops  Pulmonary Function Tests ophthalmic and maxillofacial anesthesia by tiruzer.h 150 Dangers of IV sedation in dentistry  Airway contamination. Contamination may be by blood, irrigation fluids, secretions or dental material.  Since it is essential to keep the cough reflex active  Airway obstruction. The tongue may fall back and obstruct the airway after excessive sedation.  There may be foreign matter in the pharynx, e.g. packs, fluid, secretions and dental material.  Hypoventilation, hypotension and loss of consciousness are all side effects of the drugs used. ophthalmic and maxillofacial anesthesia by tiruzer.h 151 Guidelines for using IV sedation in dental surgery  Patient selection. Intravenous sedation is not ideal for small children  Patients should be ASA 1 or 2.  IV sedation is not recommended for patients with medical conditions such as asthma, hypertension, heart disease ophthalmic and maxillofacial anesthesia by tiruzer.h 152 Reference.Anesthesia & Co-existing Diseases, 3rd Edition. Robert K.Stoelting.. Clinical Anesthesia,Edition. Paul G.Barash.. Clinical Anesthesiology, 7th Edition G.Edward Morgan.. Principles & Procedures In Anesthesiology Philip L.Liu  Anesthesia of each case ophthalmic and maxillofacial anesthesia by tiruzer.h 153  THANK YOU ophthalmic and maxillofacial anesthesia by tiruzer.h 154