Corneal Reflex Testing in the Evaluation of a Comatose Patient: An Ode to Precise Semiology and Examination Skills
The corneal reflex assesses the integrity of the trigeminal and facial cranial nerves. This brainstem reflex is fundamental in neuroprognostication after cardiac arrest and in brain death determination. We sought to investigate corneal reflex testing methods among neurologists and general critical care providers in the context of neuroprognostication following cardiac arrest.
This is an international cross-sectional study disseminated to members of the Neurocritical Care Society, Society of Critical Care Medicine, and American Academy of Neurology. We utilized an open Web-based survey (Qualtrics®, Provo, UT, USA) to disseminate 26 questions regarding neuroprognostication practices following cardiac arrest, in which 3 questions pertained to corneal reflex testing. Descriptive statistical measures were used, and subgroup analyses performed between neurologists and non-neurologists. Questions were not mandatory; therefore, the percentages were relative to the number of respondents for each question.
There were 959 respondents in total. Physicians comprised 85.1% of practitioners (762 out of 895), of which 55% (419) identified themselves as non-neurologists and 45% (343) as neurologists. Among physicians, 85.9% (608 out of 708) deemed corneal reflex relevant for prognostication following cardiac arrest (neurologists 84.4% versus non-neurologists 87.0%). A variety of techniques were employed for corneal reflex testing, the most common being “light cotton touch” (59.2%), followed by “cotton-tipped applicator with pressure” (23.9%), “saline or water squirt” (15.9%), and “puff of air” (1.0%). There were no significant differences in the methods for testing between neurologists and non-neurologists (p = 0.52). The location of stimulus application was variable, and 26.1% of physicians (148/567) apply the stimulus on the temporal conjunctiva rather than on the cornea itself.
Corneal reflex testing remains a cornerstone of the coma exam and is commonly used in neuroprognostication of unconscious cardiac arrest survivors and in brain death determination. A wide variability of techniques is noted among practitioners, including some that may provide suboptimal stimulation of corneal nerve endings. Imprecise testing in this setting may lead to inaccuracies in critical settings, which carries significant consequences such as guiding decisions of care limitations, misdiagnosis of brain death, and loss of public trust.
KeywordsHeart arrest Cardiac arrest Neuroprognostication Outcome assessment Corneal reflex Blinking reflex
Dr. Carolina B. Maciel has received the Claude D. Pepper Older Americans Independence Center Junior Scholar award that supports pre-clinical studies of mechanisms of secondary brain injury in a rodent cardiac arrest model.
CBM, MMB, TSY and DMG conceived the presented study and developed the survey. CBM and TSY drafted the manuscript. JJT and MBD provided critical contributions to data analyses. All authors revised to provide critical contributions to the final manuscript.
Source of Support
This study was supported by the Department of Neurology of Yale University.
Conflict of interest
Dr. Maciel, Dr. Youn, Dr. Barden, Ms. Zhou, Dr. Pontes-Neto, Dr. Silva, Dr. Theriot, and Dr. Greer have nothing to disclose. Dr. Dhakar reports personal fees from Adamas Pharmaceuticals, other from UCB Biopharma, other from Marinus Pharmaceuticals, outside the submitted work.
Ethical Approval/Informed Consent
The Yale Institutional Review Board approved this study and granted waiver of consent.
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