Clinical Scenario

A 6-year-old male with recent-onset squint (strabismus) was scheduled for an MRI brain with contrast under anesthesia. Although the procedure may appear routine, the sudden appearance of a squint raises concern for raised intracranial pressure (ICP) or an intracranial mass lesion. This makes the anesthetic plan especially important, as it must prioritize both neurological stability and safe sedation.

Why the Squint Matters

A new-onset squint in a child is not a trivial finding. It can indicate significant underlying neurological disease. In particular, the sixth cranial nerve (abducens) is vulnerable because of its long intracranial course. When stretched by raised ICP, the nerve’s function is compromised, often resulting in esotropia (inward deviation of the eye). This clinical sign prompts further investigation to exclude conditions such as space-occupying lesions, hydrocephalus, or post-viral neuropathy.

Anesthetic relevance: Raised ICP alters both drug selection and airway management. Sedatives or airway maneuvers that increase intracranial pressure, such as coughing, straining, or hypoventilation, must be avoided.

References:

• Ropper AH, Samuels MA, Klein JP. Adams and Victor's Principles of Neurology. 11th ed. New York: McGraw-Hill; 2019.
• Yano H, Hirano T, Matsui T, Yamaura A. Abducens nerve palsy and increased intracranial pressure. Neurosurgery. 1984;15(6):935–8.

Preanesthetic Evaluation

The preoperative assessment should focus on:

• Identifying symptoms of raised ICP, such as headache or vomiting
• Reviewing seizure history or signs of developmental delay
• Ensuring appropriate fasting status and hydration

In this case, the child had fasted for six hours but had refused intravenous fluids, increasing the risk of dehydration or hypoglycemia.

Relevance: Early recognition of neurological symptoms influences the choice of anesthetic drugs and ventilation strategy. Avoiding events that can worsen ICP is critical.

References:

• Litman RS, Kost-Byerly S, Berkowitz ID. Chapter 32: Preoperative evaluation of pediatric patients. In: Cote CJ, Lerman J, Anderson BJ, editors. A Practice of Anesthesia for Infants and Children. 6th ed. Philadelphia: Elsevier; 2019. p. 808–21.
• Engelhardt T, Weiss M. A child with a full stomach. Curr Opin Anaesthesiol. 2012;25(3):342–7.

Anesthetic Technique and Medication Choices

Induction agents:

• Glycopyrrolate 0.05 mg IV: reduces secretions and prevents bradycardia.
• Midazolam 0.5 mg IV: provides anxiolysis and sedation.
• Fentanyl 40 micrograms IV: offers analgesia and blunts the stress response.
• Propofol 10 mg IV: ensures a smooth induction, decreases cerebral metabolic rate, and lowers ICP.

Maintenance:

• Dexmedetomidine 10 micrograms diluted in 50 mL IV fluid, providing light sedation while maintaining spontaneous ventilation.
• Propofol 5 mg IV at 20 and 40 minutes, administered as needed for movement suppression or contrast injection.

Airway:

• A face mask with spontaneous ventilation was used, avoiding airway instrumentation and reducing the risk of ICP surges.

Rationale:

This combination ensures adequate sedation and analgesia while maintaining spontaneous breathing. It minimizes fluctuations in intracranial pressure and avoids complications associated with intubation in the MRI suite.

References:

• Mason KP. Pediatric Sedation Outside of the Operating Room: A Multispecialty International Collaboration. 2nd ed. New York: Springer; 2015.
• Mahmoud M, Mason KP. Dexmedetomidine: review, recent clinical trials, and case reports. Anesthesiol Clin. 2017;35(4):761–74.
• Tobias JD. Propofol sedation for diagnostic imaging procedures in children. Pediatr Radiol. 2002;32(8):558–62.

Intraoperative Monitoring and Management

Monitoring included:

• ECG, pulse oximetry (SpO₂), and non-invasive blood pressure
• Capnography to maintain an end-tidal CO₂ of 35–40 mmHg

Why spontaneous ventilation?

Allowing the child to breathe spontaneously avoids the need for positive-pressure ventilation or endotracheal intubation. This reduces the risk of increasing ICP, and it simplifies management in the MRI environment, where access to the airway can be limited.

MRI-specific considerations:

• Use of MRI-compatible monitors and equipment
• Awareness of restricted access once the child is inside the bore
• Readiness to manage airway or hemodynamic events promptly despite limited access

References:

• Malviya S, Voepel-Lewis T, Tait AR. Sedation and general anaesthesia in children undergoing MRI and CT: adverse events and outcomes. Br J Anaesth. 2000;84(6):743–8.
• American Society of Anesthesiologists. Practice advisory on anesthetic care for magnetic resonance imaging. Anesthesiology. 2015;122(3):495–520.

Recovery and Postoperative Considerations

At the conclusion of the scan:

• 10 mL of 25% dextrose IV was administered to prevent hypoglycemia after prolonged fasting and limited fluid intake.
• The child regained consciousness smoothly and was transferred to the recovery area fully awake.

Relevance:

Children are particularly susceptible to hypoglycemia after fasting. Administering dextrose ensures stable recovery and reduces the risk of agitation or delayed emergence.

References:

• Engelhardt T, Webster NR. Pulmonary aspiration of gastric contents in anesthesia. Br J Anaesth. 1999;83(3):453–60.
• Short JA, Hulka F, Riegle EV. Hypoglycemia and anesthetic management in infants and children. Anesth Analg. 1976;55(4):504–10.

Conclusion

This case illustrates the importance of tailoring anesthesia to the child’s clinical condition. A new squint in a child may signal increased intracranial pressure or an intracranial lesion, and therefore requires special attention. By selecting induction and maintenance strategies that preserve spontaneous ventilation and minimize rises in ICP, anesthesia can be delivered safely even in the high-risk environment of the MRI suite.