The ciliospinal reflex in pentobarbital coma.
OBJECTIVE
This study was conducted to delineate the ciliospinal reflex (CSR), which is defined as pupillary dilation caused by a noxious stimulus to the face or head. The authors anecdotally observed that patients in a pentobarbital coma have a CSR that can mimic pathological conditions. A pentobarbital coma obscures the results of the neurological examination in patients with potentially life-threatening cerebral edema; pupil size and reactivity are the only readily monitored signs. Any condition that incorrectly suggests evolving intracranial pathological processes can lead to unnecessary clinical actions.


METHODS
The authors evaluated six consecutive patients in the neurointensive care unit in whom a pentobarbital coma had been induced, documenting the presence and duration of the CSR. The CSR was always bilateral and symmetrical, manifesting as enlarged (6-8 mm), seemingly nonreactive pupils continuing from 1 to 6 minutes and was usually seen after routine nursing maneuvers. The pupils appeared nonreactive to short flashes of direct light but did react if longer flashes were used.


CONCLUSIONS
Recognition of the CSR can potentially lead to reduction of unnecessary transportation and complicating medical interventions in critically neurologically ill patients in whom a pentobarbital coma has been induced.
Andrefsky
J C
JC
Department of Neurosurgery, Cleveland Clinic Foundation, Ohio 44195, USA. andrefj@cesmtp.ccf.org
Frank
J I
JI
Chyatte
D
D
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001929:Brain Edema / Q000503:physiopathology / Q000628:therapy; D003128:Coma / Q000139:chemically induced* / Q000451:nursing; D004569:Electroencephalography; D018757:GABA Modulators / Q000627:therapeutic use*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery; D007427:Intracranial Pressure / Q000502:physiology; D008027:Light; D008875:Middle Aged; D009460:Neurologic Examination; D010424:Pentobarbital / Q000627:therapeutic use*; D010775:Photic Stimulation; D011680:Pupil / Q000187:drug effects; D012025:Reflex, Pupillary / Q000187:drug effects* / Q000502:physiology; D013226:Status Epilepticus / Q000628:therapy; D013997:Time Factors
D018757:GABA Modulators; D006993:Hypnotics and Sedatives; D010424:Pentobarbital