Preferred Anesthetic Technique for Pediatric Glaucoma EUA
For exam under anesthesia (EUA) to measure IOP, corneal dimensions, optic nerve cupping, gonioscopy, axial length, and refraction in suspected pediatric glaucoma, use sevoflurane or propofol-based general anesthesia with remifentanil, avoiding ketamine and minimizing succinylcholine use, as both propofol and sevoflurane provide accurate IOP measurements that reflect awake values when combined with short-acting opioids. 1, 2
Optimal Anesthetic Agents
Primary Induction and Maintenance Options
Sevoflurane (0.5-2% end-tidal concentration) is an excellent choice because it does not significantly alter IOP from awake measurements across a wide concentration range and allows smooth inhalational induction in pediatric patients 1, 2
Propofol (bolus 1.5-2.0 mg/kg, maintenance 3.0-7.0 mg/kg/h) is equally valid as it produces IOP measurements comparable to the awake state, though it may reduce IOP slightly more than sevoflurane (6.0 vs 8.9 mmHg during induction) 3, 1
Remifentanil (10 μg/kg/h or 1 μg/kg bolus) should be combined with either agent as it effectively attenuates IOP increases during intubation and provides stable conditions for accurate measurement 3, 4
Critical Agents to Avoid or Minimize
Ketamine must be avoided as it is the only intravenous anesthetic that may increase IOP, making it unsuitable for glaucoma evaluation 5, 2
Succinylcholine increases IOP significantly and should be avoided if possible; if neuromuscular blockade is required, use non-depolarizing agents like vecuronium or atracurium which produce stable or slightly decreased IOP 5, 4
Practical Anesthetic Protocol
Recommended Sequence
Inhalational induction with sevoflurane is preferred in pediatric patients for smooth, cooperative induction without IV access initially 1, 2
Alternatively, IV induction with propofol (1.5-2.0 mg/kg) combined with remifentanil (1 μg/kg) provides excellent IOP control and rapid onset 3, 4
Maintain anesthesia with sevoflurane 0.5-2% or propofol infusion 3-7 mg/kg/h, both combined with remifentanil infusion 10 μg/kg/h for optimal IOP stability 3, 1
Airway Management Considerations
Laryngoscopy and intubation transiently increase IOP, which can be minimized by adequate depth of anesthesia with remifentanil pretreatment 4, 2
Laryngeal mask airway (LMA) may be preferable to endotracheal intubation when feasible, as it causes less IOP elevation 2
If intubation is necessary, administer remifentanil 1 μg/kg 3 minutes prior to laryngoscopy to attenuate the IOP spike 4
Key Clinical Caveats
Timing of IOP Measurement
Measure IOP after adequate anesthetic depth is achieved but before excessive depth causes artifactual lowering; the optimal window is during stable maintenance anesthesia 1, 2
Avoid measuring during induction or emergence when hemodynamic fluctuations and inadequate anesthetic depth can falsely elevate IOP 2
Hemodynamic Stability
Maintain normocapnia as hypercapnia increases IOP while hypocapnia decreases it; target end-tidal CO2 of 35-40 mmHg 2
Avoid excessive anesthetic depth as all volatile and IV anesthetics reduce IOP in a dose-dependent manner, potentially masking true elevated IOP 5, 2
Body Positioning
- Position the patient supine with head elevated 15-30 degrees if possible, as body position affects IOP measurements 2
Tonometry Technique Under Anesthesia
Equipment Selection
Topical anesthesia is already provided by general anesthesia, allowing use of any tonometry method including pneumotonometer, Goldmann applanation, or rebound tonometry 6
Goldmann applanation tonometry remains the reference standard for EUA when the cornea is clear and regular, though alternative methods may be needed for corneal edema or irregularity 6
Pneumotonometer or rebound tonometry can be used as alternatives, particularly if corneal abnormalities are present 6, 7