Case 41 - Retinal Detachment

Question 1

What are the advantages and disadvantages of regional anesthesia during retinal sx?

Answer 1

Regional Anesthesia preformed via - retrobulbar, peribulbar, sub-Tenon block

Advantages

• dec time in operating room
• dec stress response
• faster recovery
• avoid PONV
• dec risk of cognitive dysfunction in susceptible pts

Disadvant

• restless patients –> ocular injury due to movement
• unsecured airway
• incomplete analesia
• surgery outlasting block

Risks of regional

• retrobulbar hemorrhage
• injury to optic nerve
• globe perf
• intravascular injection –> LAST
• injection into dural sheath of optic nerve –> CSF injection –> high spinal

Question 2

what are advant and disadvant of general anes during retinal sx?

Answer 2

Advant

• motionless surgical field
• unlimited duration of anesthesia

Disadvant

• coughing or bucking –> can disrupt surgical field
• PONV post-op –> disrupt surgical repair
• increase time required for induction and emergence
• prolong period in PACU

Question 3

retrobulbar and peribulbar blocks provide conduction block of which nerve?

Answer 3

• intraorbital sensory divisions of the opthalamic branch of trigeminal nerve

Question 4

what are issues to consider during general anesthesia for retinal surgery?

Answer 4

1) Airway

• limited access to airway - at risk for disconnect
• consider Ring-Adair-Elwyn (RAE) tube or flex LMA

2) nitrous oxide

• if gas buble is injected, do not use N2O –> can expand gas bubble
• assoc with PONV –> can disrupt surgical repair (inc IOP)

3) Emergence
* avoid coughing or bucking –> consider TIVA with propofol
4) PONV
* can increase IOP and disrupt surgical repair. prevent and tx accordingly (TIVA, multimodal antiemetic therapy)

Question 5

What is the oculocardiac reflex?

Answer 5

Components:

• Afferent limb - opthalmic division of trigem neve
• Gasserian ganglion (aka trigmenial ganglion)
• Efferent limb - vagus nerve
• traction on globe or extraocular muscles initiates reflex
• see cardiac dysrhythmias, such as bradycardia

Question 6

how do you tx oculocardiac reflex?

Answer 6

• tell sx to stop surgical stimulation
• tx with anticholinergic
• can prevent by prophylatic admin of anticholinergic

Question 7

Are you concerened with a patient entering you OR who recently is s/p gas bubble injection for retinal detachment?

Answer 7

• N2O should be avoided for 10-28 days s/p gas bubble injection
• Nitrous oxide can expand gas bubble and disrupt surgical repair