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Updated: Feb 13, 2026

Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Pitfall in Pupillometry: Exaggerated Ciliospinal Reflex in a Patient in Barbiturate Coma Mimicking a Nonreactive
Naresh Mullaguri1, Nakul Katyal2, Aarti Sarwal3
1Neurology, Cleveland Clinic Ohio.
Abstract:
Although a neurological examination is fundamental to the evaluation of comatose patients, it is less reliable in a medically induced coma. A commonly misinterpreted finding in patients in a pentobarbital coma is altered pupillary reactivity secondary to an exaggerated ciliospinal reflex. Recognizing an exaggerated ciliospinal reflex in patients in a pentobarbital coma is important and may prevent unnecessary intervention. We present a patient induced in a pentobarbital coma for the treatment of status epilepticus who exhibited a nonreactive pupil secondary to an exaggerated ciliospinal reflex confirmed by pupillometry. We also discuss the anatomy of the ciliospinal reflex and literature regarding its clinical relevance.
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