Propofol and pupillary diameter

Q: Propofol has a dose-dependent effect on pupillary diameter?

A) True

B) False

Answer: A

A less known clinical effect of propofol is its dose-dependent effect on pupillary diameter. It has an inverse relationship with pupillary diameter. Moreover, this dose-dependent effect correlates well with bispectral index (BIS) value. A recent randomized trial of 40 patients from France confirmed this relationship. This is probably due to propofol's subcortical effect on pupillary diameter, and it correlates with its effect on the cortex (aka BIS value). 

This can be a valuable clinical tool at bedside to gauge the depth of hypnosis.

#pharmacology

#neurology

Reference:

Sabourdin N, Meniolle F, Chemam S, et al. Effect of Different Concentrations of Propofol Used as a Sole Anesthetic on Pupillary Diameter: A Randomized Trial. Anesth Analg 2020; 131:510.