Introduction
Pupil size and reactivity have been studied in the adult and pediatric
populations in an attempt to objectively quantify pain. Previously
conducted studies have demonstrated pupillometry as a promising
biomarker for objective pain measurement.1-3 A 2012
study demonstrated the significant correlation between patient verbally
reported pain and pupillary dynamics in order to guide narcotic
administration.2 Another study showed that
pupillometry is a more sensitive test for pain assessment and response
to medication than other hemodynamic markers, including vital
signs.3 Factors including patient age, sex, and
ethnicity have been previously studied in order to better understand the
potential variables affecting pupil dynamics and establish a set of
normal values. Regarding pupillary dynamics in younger patients, Brown
et al. evaluated the pediatric population and demonstrated a slight
change in pupil dynamics across pediatric age groups as well as
differences across various ethnicities.1
Pupillometry is conducted using a hand-held device that measures a
variety of pupil dynamics following exposure to an infrared light
stimulus. The parameters of pupil constriction and dilation velocity as
well as minimum and maximum pupil sizes are the most significant
categories used for comparison of patient populations. The testing is
noninvasive, quick, and carries little to no risk for the patient,
making pupillometry an ideal tool for pain measurement.
The clinical application of pupillometry is particularly useful in the
young pediatric population as it is more difficult to understand
subjective patient-reported pain, and an objective pain evaluation
measurement is needed. For example, in the pediatric sickle cell disease
population, vaso-occlusive crisis is a common complication that presents
with acute pain. Vaso-occlusive pain crises are often over or
undertreated due to fear of medication side-effects, possible addiction,
and variable tolerance.4 Quantifying acute pain and
response to treatment has been difficult due to dependence on subjective
measures. In this study, we aim to measure pupillometry measurements in
pediatric patients with sickle cell disease as a first step to establish
normative data for future utilization in cases of acute pediatric
vaso-occlusive pain crisis.1