Download Eye surgery

Eye surgery
Requirements for eye surgery:
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Akinesia of the eye
Intense analgesia
Minimal bleeding (avoid HT or movement of eye)
Management of oculo-cardiac reflex
Control of intra-ocular pressure (IOP)
Beware of drug interactions
Smooth recovery with no PONV
Oculo-cardiac reflex
• Occurs with pulling of eye muscles/pressure on eye ball
• Afferent = N V (V1), efferent = N X → bradycardia
• Most common in children for strabismus repair, but can occur
during any ophthalmic procedure
• Management:
1. Ask surgeon to stop pulling on muscles
2. Confirm adequate depth of anaesthesia
3. Administer atropine (0.02 mg/kg) if bradycardia persists
4. The reflex eventually fatigues itself with repeated pulling
and release of eye muscles
Control of intra-ocular pressure
• Eye cavity = hollow sphere with a rigid wall. If contents ↑→
IOP ↑→ extrusion of ocular contents through open
surgical/trauma wound
• Anaesthesia can → ↑ IOP due to
1. laryngoscopy/ intubation (HT),
2. airway obstruction, coughing, ↑ CVP, Trendelenburg
position (↓ venous drainage)
3. ↑ PaCO2 (vasodilatation →↑ eye blood flow
4. Drugs: Ketamine, suxamethonium →↑ IOP
• Other anaesthetic drugs (opioids, induction agents, muscle
relaxants do not ↑ IOP and are thus save
Drug interactions
• Ecothiopate is a pseudocholinesterase (pCE) inhibitor
used to ↓ IOP but it can prolong the action of
suxamethonium (which is broken down by pCE)
• Timolol is a β-blocker used in the eye to ↓ IOP but
can cause bradycardia, asthma etc
Strabismus surgery
• Oculo-cardiac reflex = common
• ↑ incidence of malignant hyperthermia
(temperature monitoring = NB)
• ↑ incidence of PONV (consider
prophylactic anti-emetics)
The open eye
• Emergency, thus can not wait for pt to be NPO
• Do rapid sequence induction (trauma delays gastric
emptying)
• Avoid Ketamine
• Consider suxamethonium (although ↑ IOP), because
it is given with IV induction agent and opioid which
both decrease IOP. Suxamethonium provide
excellent intubation conditions and thus prevents ↑
IOP due to coughing etc.
• Avoid all factors that ↑ IOP (see above)