Opthalmic Flashcards
Intraocular pressure normal
16 +/-5 mmHg
Intraocular pressure is determined by?
Mainly aqueous humour in anterior chamber, vitreous humor and blood within eye, scleral compliance and extraocular muscle tone
How anesthesia increased IOP
Venous congestion, coughing/bucking, pressure on eye by face mask, extraocular muscle contraction by succ, HTN, hypoxemia, hypoventilation, ketamine, sympathetic stimulation (dilates eye)
Oculocardiac reflex defined
“five and dime” Decrease in heart rate and blood pressure due to afferent limb of trigeminal nerve to cardio inhibitory vagal center efferent to vagus
Oculocardiac reflex management
Notify the surgeon to stop, optimize oxygenation and ventilation, possibly atropine 20 mcg/kg or glycopyrrolate
Echothiophate
Prolong succ and mivacurium
Scopolamine
Central anticholinergic
Cataract surgery and anesthesia
phacoemulsification with IOL (intraocular lens placement), sometimes retrobulbar block with short acting sedative/narcotic and then MAC
Retrobulbar block gets which nerves?
Trigeminal, Trochlear, Abducens, Oculomotor
Retrobulbar block complications
Oculocardiac reflex, hemorrhage, globe puncture, intradular/vascular injection
Brainstem anesthesia
Get loss of consciousness, apnea and cardiac instability, possibly mydriasis and contralateral eye block
Peribulbar block
Needle outside cone- decreases complications but get less motor block and need to use more volume of local
Sub-Tenon’s block
Instilling local by blunt cannula into space between globes sclera and sub-Tenon’s capsule
when is Facial nerve block used
If surgeon does not want blinking
Trabeculectomy
creates a new drainage system for eye - usually with glaucoma surgery
Glaucoma anesthesia
Sedation with block, if GA use smooth induction to minimize increase in IOP
Squints surgery anesthesia
strabismus surgery - done under GA, high incidence of OCR and PONV, possibly increased risk of MH, avoid ketamine due to nystagmus
Keratoplasty
corneal surgery from penetrating to full thickness- can be done under MAC or GA
Blepharoplasty
Eyelid surgery to remove excessive tissue
Ptosis repair
Corrects dropping
Dacrocystorhinostomy
Repair of lacrimal sac communication to nasal passage (cocaine works well except with old bad hearts)
