This brief presentation does not cover all of the ophthalmology surgeries, but will give you a brief review about what is what. It starts with eye anatomy, physiology, pharmacology and leads up to anaesthesia considerations.

1. ANAESTHESIA IN
OPHTHALMOLOGY
DR SARDAR SAUD ABBAS
PG-III, ANAESTHESIA

2. CONTENTS
 Anatomy
 The effect of cardiac and respiration on IOP
 Effects of anaesthetic agents on IOP
 Oculocardiac Reflex
 Intraocular gas expansion
 Systemic effects of ophthalmic medication
 Regional Anaesthesia in ophthalmic surgery
 Case Discussion

3. ANATOMY OF EYE

4. NERVE SUPPLY OF EYE
Muscle of the eye
 Superior, Medial, Inferior, inferior oblique rectus muscles are supplied by
occulomotor nerve.
 Occulomotor nerve also supplies superior palpebral levator muscle
 Lateral rectus is supplied by Abducent nerve
 Superior oblique is supplied by Trochlear nerve

5. ANS of the eye

6. BLOOD SUPPLY OF EYE

7. The effect of cardiac and respiration on
IOP
Central venous pressure:
 Increase in CVP increases IOP, decreases in CVP decreases IOP.
Arterial blood pressure:
 Increase in arterial blood pressure also increases IOP and vice versa.
PaCO2:
 Increase in PaCO2 concentration (hypoventilation) increases IOP.
 Decrease in PaCO2 concentration (hyperventilation) decreases IOP.
PaO2:
 Increase in PaO2 doesn’t have significant effect on IOP
 But decrease in PaO2 increases IOP
Any event that alters these parameters (eg, larygoscopy, airway obstruction, coughing, intubation, tredelenburg
postion) can affect IOP.

8. Effects of anaesthetic agents on IOP
Inhaled anaesthetics:
 All inhalation agents decrease IOP. Volatiles agents decreases IOP more than
nitrous oxide.
IV anaesthetics:
 Propofol, Benzodiazepines, Opiods decreases IOP.
 Ketamine usually raises arterial blood pressure, so it increases IOP.
Muscle relaxants:
 Succinylecholine increases IOP by 5-10 mmHG for 5-10mins after administration of
drug.
 Non depolarizing muscles relaxant either decreases or have no effect

9. Oculocardiac Reflex
 It is a reflex resulting in severe bradycardia, leading to cardiac arrest
What causes oculocardiac reflex?
 Traction on extra ocular muscles
 Pressure of the eye ball
 Trauma to the eye
 Retrobublar block administration

11. Management
 Immediate cessation of surgery
 Confirmation of adequate ventilation, oxygenation and depth of anaesthesia
 Administer IV atropine (10mcg/kg)
Anticholinergics(atropine, glycopyrolate) used as premedication usually decrease the
incident
IV works better than IM
Anticholinergics should be given with caution to patients with coronary artery disease

12. Intraocular gas expansion
Gas bubble or Sulfur hexafluoride are used in retinal detachment
 Gas bubble is absorbed in 5 days into the bloodstream
 Sulfur hexafluoride is absorbed into the blood after 10 days
 During these gas insertion nitrous is stopped 15 min prior to the insertion.
 Nitrous oxide tends to absorb more readily (35 time more readily absorbed in
blood than nitrogen), it expands the gas bubble
 Which leads to unnecessary increase in IOP after surgery.

13. Systemic effects of ophthalmic medication.

14. Regional Anaesthesia in ophthalmic
surgery
 Retrobulbar block
 Peribulbar block
 Facial nerve block
Van Lint, Atkinson and O’brien technique
 Topical Anaethesia
0.5% proparacaine drops, repeated after 5 min interval, 5 applications
followed by anaesthetic gel (lidocaine chlorhydrate plus 2% methyl-cellulose)

17. Case Discussion
A 6 year old girl came to the emergency with
a history of fire arm injury to the eye. Quick
examination revealed intraocular contents
presenting at the wound. Girl is taken to the
emergency OT for repair of the ruptured
globe. Make a plan for her safe induction.

18. Pre-op Evaluation
 History of the patient
 Physical and airway examination
 Most important question is when was the last meal taken by the patient
 If it is less than 8 hours patient should be considered full stomach
 Because pain also decreases gastric emptying
Significance of a full stomach in a patient with an open globe injury?
 It increases risk of further injury to the eye
 Prevent further injury to the eye, because it further increases IOP
 We have to prevent pulmonary aspiration.

19. How to prevent increase in IOP?

20. Avoid direct pressure on the globe:
 Patch eye with fox shield
 No retrobulbar or peribulbar injections
 Careful face mask technique
Avoid increase in CVP:
 Prevent coughing during induction and intubation (1.5mg/kg IV Lidocaine, good
analgesia, adequate depth of anaesthesia before intubation)
 Ensure a deep level of muscle relaxation prior to laryngoscopy
 Avoid head down position of the patient
 Awake extubation
Avoid pharmacological agent that increase IOP

21. How to prevent Aspiration?

22. Premedication:
 Metochlorpromide
 Histamine H2-receptor antagonist (ranitidine 50mg, cimetidine 300mg, famotidine
 Sodium citrate 15-30 ml orally (works within 30-60 min)
Evacuation of gastric contents:
 Nasogastric tube should be passed and suction should be done (not in this case
patient is young. If you pass NG in awake and young patient it will cause cough and
straining which increases IOP). In young patients NG can be passed after intubation
Rapid-sequence induction:
 Cricoid pressure
 Rapid induction with rapid onset of paralysis
 Avoid positive pressure ventilation via mask
 Intubate as soon as possible
Extubation awake

23. Recommended induction agent
 Ideal agent for induction is propofol (etomidate if patient was a cardiac patient but
not in this case)
 Both propofol and etomidate reduced intraocular pressure
 Ketamine increases arterial blood pressure which leads to transient increase in IOP,
not recommended
 Propofol does not decrease hypertensive response that is caused by laryngoscopy
 Which can be reduced by prior administration of:
Fentanyl 1-3mcg/kg
Remifentanil 0.5-1 mcg/kg
esmolol 0.5-1 mcg/kg
Lidocaine 1.5 mg/kg

24. Choice of muscle relaxant for Rapid
sequence induction
 There is a conflict but worth knowing, pre administration of 1/10th dose of non
depolarizing muscle relaxant before succinylcholine decreases the increase in IOP.
 There is also less case report documenting further eye injury caused by
succinylcholine.
 Succinylcholine still is drug of choice in this case for RSI.
 Non depolarizing muscle relaxant doesn’t increases IOP and cause further damage
to the.
 NDMR that can be used for RSI is rocuronium 0.6-1.2 mg/kg

25. Why Awake extubation?
 Pre medication to reduce gastric pH and Volume
 And adequate suction can decrease risk of aspiration but not completely diminish
it
 There is risk of aspiration at extubation too
 Therefore, extubation must be delayed until patient is awake and has intact airway
reflexes.
 Coughing and gag reflex can be blunted with lidocaine and afentanil.

26. Thank You