Pupillary Responses to Dilute Pilocarpine in Brain Death and Comatous Patients

ABSTRACT

Recently, it is reported that preganglionic oculomotor nerve palsies shows denervational supersensitive pupillary responses to dilute parasympathomimetic agents and this phenomenon is in inverse proportion to consciousness level. We measured pupillary diameters of 10 brain death patients(20 eyes) and 10 comatous patients (20 eyes). After we instilled 0.06% pilocarpine to patients that initial pupillary diameter is over 4.0mm(13 eyes in brain death group, 5 eyes in comatous group), we compared pupillary responses of two groups to evaluate whether this helps diagnosis of brain death. If pupillary diameter was changed over 25%(compared to initial diameter), we considered it positive. In comatous group, no one was positive. But in brain death group, 11 cases were positive(84.6%). It revealed significant difference statistically(P<0.05). Mean change of pupillary diameter to 0.06% pilocarpine was 0.46mm(9.35%) in comatous group, and 2.62mm(47.72%) in brain death group. With above results, we concluded that pupillary response to dilute parasympathomimetic agents is a useful indicator for diagnosis of brain death.