Mod9: Oculocardiac Reflex Flashcards
Ocular Physiology
Oculocardiac Reflex
Innervation
Trigeminal (V) nerve afferent pathway
Vagus (X) nerve efferent pathway
Other ways to remember Innervation of the OCR
Five & dime reflex
(Five for CN V & dime for CN X)
or
TAVE!!!!
Trigeminal Afferent - Vagus Efferent
Ocular Physiology
Oculocardiac Reflex
Causes:
Traction extraocular muscles
(Esp. medial rectus)
Pressure on globe
Retrobulbar block
Ocular manipulation
Ocular Physiology
Oculocardiac Reflex
Most commonly seen in which types of surgeries?
Pediatrics
Strabismus surgery
Ocular Physiology
Oculocardiac Reflex
Manifestations:
Bradycardia (most typical)
Bigeminy
Nodal
Ectopic beats
ASYSTOLE
Nausea
Ocular Physiology
Attenuation of Oculocardiac Reflex
Is Atropine prophylaxis useful?
Atropine immediately prior to surgery more effective
than IM premed (not effective)
0.4 mg IM → no vagolytic effect after 60min → no value in prevention or treatment
0.4 mg IV→ effective for 30min in preventing bradycardia a/w OCR
Routine prophylaxis controversial
because Doses > 0.5 mg IV → tachycardia → detrimental in pt’s with CAD
Ocular Physiology
Attenuation of Oculocardiac Reflex
What else could you do besides Atropine prophylaxis, to prevent OCR?
Retrobulbar block once set, no problem!!!
(but may elicit during placement)
Deep inhalational anesthetic
Ocular Physiology
Oculocardiac Reflex: Treatment
Stop surgical stimulation/traction until HR increases
Confirm adequate anesthetic depth
Infiltration local anesthetic into rectus muscles
(Takes time)
Reflex often fatigues (self-extinguishable) without additional therapy
Atropine 10ug/kg if arrhythmia persists
Ophthalmic surgery
Preoperative Evaluation
General patient population typically of what age?
< 10 yo
or
> 55 yo
Ophthalmic surgery
Preoperative Evaluation of Pediatric patients
concentrates on h/o:
Congenital
Metabolic
Musculoskeletal disorders
Ophthalmic surgery
Preoperative Evaluation of Adults patients
concentrates on h/o:
Multiple health problems
CHF, HTN, COPD, DM, dementia
Determine optimization
Continue routine medications in general
HOLD ASA/coumadin
Preoperative lab testing
Based on history/physical
Many on anticoagulants → PT/PTT necessary
Ophthalmic surgery - Preoperative Evaluation
Ophthalmic drugs they are already on
Concern:
Consider anesthetic ramifications of ophthalmic drugs
Topically administered drugs are absorbed by vessels in conjunctival sac and nasolacrimal duct mucosa at rate intermediate between absorption following IV/SQ administration.
Ophthalmological topical phenylephrine (10%)is used to dilate eye for surgery.
1 drop = 5mg.
Toxic dose of phenylephrine = 10mg!!
Ophthalmic surgery - Preoperative Evaluation
Topical or regional vs. general anesthesia
Evaluate suitability for this through:
Ability to follow commands
Ability to lie motionless (tremors, chronic cough, arthritis)
Ability to lie flight (SOB, orthopnea, dyspnea)
Ability to tolerate face covered with surgical drapes (claustrophobia)
Ophthalmic surgery
Anesthetic Techniques
Regional anesthesia
Topical anesthesia
General anesthesia
Ophthalmic surgery - Anesthetic Techniques
Regional anesthesia
Options:
Retrobulbar block
Peribulbar block
Facial nerve block
Ophthalmic surgery
Anesthetic Techniques
Which is safer?
Inconclusive evidence that one is safer than other
Ophthalmic surgery
Anesthetic Techniques
Factors influencing choice:
Nature/duration surgery
Coagulation studies
Patients ability to communicate/cooperate
Often dictated by the surgeon