Anesthesia Considerations for Retinal Surgery

Retinal surgeries, including vitrectomy, retinal detachment repair, and macular surgery, require meticulous anesthetic management due to patient positioning, intraocular gas use, and high risk of postoperative nausea and vomiting (PONV).


1. Types of Retinal Surgeries

  1. Vitrectomy – Performed for diabetic retinopathy, retinal detachment, and vitreous hemorrhage.
  2. Scleral Buckling – Used for retinal detachment.
  3. Macular Surgery – For macular hole, epiretinal membrane.
  4. Retinal Laser Procedures – For diabetic retinopathy and vascular occlusions.


2. Preoperative Considerations

A. Patient Assessment

  • Common in elderly patients with multiple comorbidities (hypertension, diabetes, cardiovascular disease).
  • Diabetic patients may have autonomic dysfunction → risk of delayed gastric emptying and hemodynamic instability.
  • Myopia is a risk factor for retinal detachment and may indicate difficult intubation.
  • Check for previous eye surgeries (e.g., previous vitrectomy or cataract surgery).

B. Medication Review

  • Anticoagulants: Often continued if high thrombotic risk. Stop if necessary (as per ophthalmologist and cardiologist recommendation).
  • Diabetic Medications: Adjust insulin dose perioperatively to prevent hypoglycemia.

C. Ophthalmic Considerations

  • Intraocular Gas Use:
    • Gases used: Sulfur hexafluoride (SF₆) or perfluoropropane (C₃F₈).
    • N₂O should be avoided → It expands intraocular gas bubbles, increasing intraocular pressure (IOP).
    • Patients must avoid air travel until the gas bubble is absorbed (SF₆: ~2 weeks, C₃F₈: ~8 weeks).


3. Anesthetic Techniques

A. General Anesthesia (Preferred in Complex Cases)

  • Induction:
    • IV Propofol (rapid onset, antiemetic).
    • Fentanyl ± dexmedetomidine for analgesia and hemodynamic stability.
  • Airway Management:
    • LMA can be used in short procedures.
    • Endotracheal Tube (ETT) preferred in prolonged surgeries (risk of airway compromise in prone position).
  • Maintenance:
    • Sevoflurane / TIVA (Propofol-based).
    • Avoid N₂O (prevents intraocular gas expansion).

B. Regional Anesthesia (Preferred for Cooperative Adults)

  • Peribulbar Block (most common)
  • Retrobulbar Block (less common due to risk of optic nerve injury)
  • Sub-Tenon’s Block (safe alternative)
  • Drugs Used: Lignocaine 2% + Bupivacaine 0.5% ± Hyaluronidase.


4. Intraoperative Considerations

A. Patient Positioning

  • Prone or lateral positioning may be required, especially in vitrectomy.
  • Head stabilization is crucial to avoid inadvertent eye movement.

B. Intraocular Pressure (IOP) Management

  • Avoid hypercapnia (causes vasodilation and increases IOP).
  • Ensure normocapnia (EtCO₂: 35-40 mmHg).
  • Mannitol 20% (1g/kg IV) may be given if IOP is critically high.

C. Oculocardiac Reflex (OCR) Risk

  • Can occur with extraocular muscle traction.
  • Managed by stopping the stimulus and administering IV atropine (0.01 mg/kg) if bradycardia persists.

D. Fluid Management

  • Avoid excessive IV fluids, which can increase orbital congestion and raise IOP.
  • Target euvolemia with controlled fluid administration.


5. Postoperative Considerations

A. Postoperative Nausea and Vomiting (PONV)

  • Very common due to vagal stimulation.
  • Prevention:
    • Ondansetron 4-8 mg IV.
    • Dexamethasone 4-8 mg IV.
    • Propofol TIVA reduces PONV risk.

B. Pain Management

  • Minimal pain expected unless scleral buckling is done.
  • Paracetamol ± NSAIDs usually sufficient.

C. Postoperative Vision and Recovery

  • Gas-filled eye precautions:
    • Strict positioning instructions (face-down or lateral).
    • No air travel until the gas bubble dissolves.



 MCQs for Exam Preparation

  1. Which of the following intraocular gases has the longest duration of absorption?
    a) Air
    b) Sulfur hexafluoride (SF₆)
    c) Perfluoropropane (C₃F₈)
    d) Oxygen
    Answer: c) Perfluoropropane (C₃F₈)
  2. Why is nitrous oxide avoided in vitrectomy surgery?
    a) It causes bradycardia.
    b) It increases intraocular pressure by expanding gas bubbles.
    c) It leads to excessive sedation.
    d) It increases the risk of bleeding.
    Answer: b) It increases intraocular pressure by expanding gas bubbles.
  3. Which anesthetic technique is preferred in complex retinal surgeries?
    a) Peribulbar block
    b) Retrobulbar block
    c) General anesthesia
    d) Topical anesthesia
    Answer: c) General anesthesia
  4. What is the recommended positioning for a patient after retinal detachment repair with a gas bubble?
    a) Supine
    b) Lateral decubitus
    c) Prone
    d) Trendelenburg
    Answer: c) Prone
  5. Which of the following drugs is most effective in preventing PONV in retinal surgeries?
    a) Atropine
    b) Ondansetron
    c) Propofol
    d) Neostigmine
    Answer: b) Ondansetron