Yes, pupillary light reflex will remain intact when paralyzed with rocuronium
Neuromuscular blocking agents like rocuronium do not affect the pupillary light reflex because this reflex is mediated by smooth muscle in the iris, not skeletal muscle. Rocuronium only paralyzes skeletal muscle by blocking nicotinic acetylcholine receptors at the neuromuscular junction, while pupillary constriction is controlled by parasympathetic innervation through muscarinic receptors in the iris sphincter muscle.
Key Evidence Supporting Preserved Pupillary Response
The most direct evidence comes from prospective emergency department research demonstrating that all patients receiving rocuronium (27/27,100%) maintained pupillary response after rapid sequence intubation 1. This study specifically evaluated patients undergoing emergency RSI and found preserved pupillary reflexes with both rocuronium and succinylcholine (91% with succinylcholine) 1.
Additional controlled research in anesthetized patients confirmed that systemically administered neuromuscular blocking drugs (vecuronium and pancuronium) do not acutely affect pupillary light reflex, with no changes in resting pupil size, reflex amplitude, or constriction velocity 2.
Important Caveats About Confounding Factors
Ketamine Effects
While rocuronium preserves pupillary response, ketamine can depress the pupillary light reflex by approximately 50% 3. In your specific scenario with ketamine and rocuronium co-administration, the pupillary response may be diminished due to ketamine's NMDA receptor antagonism, not the rocuronium 3.
Sedation and Hypotension
Current guidelines emphasize that pupillary reflexes are prone to interference from sedatives 4. The 2025 ERC/ESICM guidelines specifically note that sedation can reduce pupil size and affect detectability of the light reflex, though automated pupillometry can detect responses even when pupils are small 4.
Hypotension itself does not directly abolish pupillary reflexes, but severe hypoperfusion could theoretically affect brainstem function. The guidelines recommend ensuring adequate blood pressure when assessing neurological function 4.
Clinical Implications for Assessment
Recent quantitative pupillometry research shows that while the Neurological Pupil Index (NPi) may decrease slightly after general anesthesia induction (from ~4.2 to ~3.3), this remains within normal range (NPi ≥3 is normal) and there is no significant change specifically attributable to rocuronium or succinylcholine administration 5.
For neurological assessment in critically ill patients, guidelines recommend waiting at least five elimination half-lives after neuromuscular blockade before clinical examination 4. However, this recommendation applies to motor examination, not pupillary reflexes, since the corneal reflex (which involves skeletal muscle for eye blinking) can be affected by muscle relaxants, but the pupillary light reflex itself remains intact 4.
Bottom Line for Your Patient
In your hypotensive female patient intubated with ketamine and rocuronium:
- The pupillary light reflex will be present (rocuronium does not block it)
- The response may be diminished due to ketamine's effects, not rocuronium
- Assess pupils to evaluate brainstem function, recognizing that reduced reactivity is more likely from ketamine or sedation than from rocuronium
- The corneal reflex (eye blink) will be absent due to rocuronium's skeletal muscle paralysis 4