Original ArticleAutomated Pupillometry as a Triage and Assessment Tool in Patients with Traumatic Brain Injury
Introduction
Traumatic brain injury (TBI) is a leading cause of mortality and disability in young adults and affects more than 60 million people every year worldwide.1,2 After early resuscitation, the initial management of patients with severe TBI revolves around a thorough yet precise neurologic assessment primarily reflected by the Glasgow Coma Scale (GCS) score, and an evaluation of the extent of injuries shown on admission computed tomography (CT).3, 4, 5 This assessment constitutes the basis of evidence on which the Brain Trauma Foundation guidelines are written.6 However, current recommendations only serve as an adjunct to clinical judgment, especially in scenarios in which the evidence is uncertain, because care is often complex and needs to be tailored to the individual needs of the injured.3,6 Moreover, these guidelines apply only after transport to treatment centers, do not address patient triage on the field or in transit, and may lead to overuse of surgical resources. The evaluation of the pupillary light reflex (PLR) using automated infrared pupillometry (AIP) has been recently established as a useful source of clinical data in the management of an array of neurologic diseases.7, 8, 9, 10 This evaluation includes the assessment of early brain herniation in ischemic stroke,11 the correlation with intracranial pressure (ICP) in patients with TBI,12 and the prediction of cerebral ischemia after aneurysmal subarachnoid hemorrhage.13 AIP changes also serve as a biomarker following cardiac arrest and extracorporeal membrane oxygenation.12,14
The objective of this study was to explore potential uses of AIP in the triage of patients with TBI. We hypothesized that patients with severe head trauma requiring an emergent intervention, including emergent surgical decompression and intracranial monitor or ventricular drain placement, would have changes in their pupillometry readings that could provide insight into their pattern and severity of injury. We aimed to explore the possibility of using this information as an adjunct to GCS and clinical examination to identify severely injured patients requiring emergent surgical treatment early and to prioritize their transfer to capable centers of care.
Section snippets
Study Population
This was a prospective observational pilot study conducted at a level 1 trauma center between November 2019 and February 2020. The AIP readings of consecutive patients who presented with a blunt TBI and abnormal imaging findings on CT in the emergency department were recorded by the assessing neurosurgery resident. Neurosurgery is consulted for every TBI with abnormal findings on brain imaging per our trauma protocol. The AIP readings were collected only once and for each side. The assessment
Results
A total of 36 patients were enrolled in the study, with 27 (75%) males and a mean age of 49.9 years (SD = 18.9) (Table 1). Fifty percent of patients (n = 18) had a high impact velocity injury, which included motor vehicle collisions (n = 14) and falls from a height (n = 4). The other half (n = 18) had low impact velocity injuries, which included falls from standing (n = 13) and assaults (n = 5). A total of 9 patients received emergent neurosurgical procedures on arrival and comprised the
Discussion
Pupillary reactivity depends on intact efferent and afferent visual motor pathways but is also influenced by spinal parasympathetic signals and cortical modulation.17, 18, 19, 20 These pathways can be disrupted by traumatic injury and induce changes registered by the pupillometer. The importance of the pupillary reflex in the assessment of patients with TBI is highlighted by the fact that the GCS-Pupil4,21 and the Full Outline of Unresponsiveness scale22,23 both include PLR assessment. However,
Conclusions
AIP may be useful in the initial triage of comatose patients after blunt TBI. A low NPI may be indicative of severe brain injury requiring an emergent surgical procedure. Pupillometry readings may provide additional data that can be helpful in the management of comatose patients with a GCS score ≤8 when their brain imaging does not show direct signs of herniation, midline shift, or increased ICP.
CRediT authorship contribution statement
Tarek Y. El Ahmadieh: Conceptualization, Methodology, Writing - original draft. Nicole Bedros: Conceptualization, Writing - review & editing, Validation. Sonja E. Stutzman: Methodology, Project administration, Resources. Daniel Nyancho: Data curation, Formal analysis. Aardhra M. Venkatachalam: Data curation, Formal analysis. Matthew MacAllister: Data curation, Investigation. Vin Shen Ban: Data curation, Investigation. Nader S. Dahdaleh: Writing - review & editing. Venkatesh Aiyagari: Writing -
Acknowledgments
We would like to thank the following individuals for contributing to our data collection and without whom this study would not have been possible: Jose Marin Sanchez, M.D., Cody Wolfe, M.D., Mary Ashley Liu, M.D., Julie Yi, M.D., Benjamin Kafka, M.D., Matthew Davies, M.D., and Awais Vance, M.D.
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2022, International Emergency NursingPilot Study of Neurologic Pupil Index as A Predictor of External Ventricular Drain Clamp Trial Failure After Subarachnoid Hemorrhage
2022, World NeurosurgeryCitation Excerpt :NPi is a composite score of pupil diameter, latency, and constriction velocity in response to light, and dilation velocity and NPi values <3.0 are considered abnormal.17,18 Abnormal NPi is associated with poor outcomes,19-23 increased ICP,17,24-26 neurologic worsening in aneurysmal subarachnoid hemorrhage,8,27-29 and other neurologic conditions8,20,21,27,30 but has not been evaluated for use during an EVD clamp trial. The purpose of this study is to extend the literature by exploring the hypothesis that NPi is a useful adjunct to predicting EVD clamp trial failure.
Inter-device reliability of the NPi-200 and NPi-300 pupillometers
2022, Journal of Clinical NeuroscienceCitation Excerpt :The neurocritically ill patients in our sample were known to be at risk for cerebral edema and it is established that cerebral dynamics such as intracranial pressure (ICP) are dynamic and may change significantly over a short period of time. Several studies have found associations between NPI and intracranial pressure [24–27], or pressure related conditions such as midline shift [28]. It is also worth noting that our PLR assessments were timed to occur when the nurse would be completing a full neurological exam, and these exams are conducted after turning off any sedative infusions.
Multimodal Neurologic Monitoring in Children With Acute Brain Injury
2022, Pediatric NeurologyCitation Excerpt :NPi has also been shown to have potential prognostic value, with depressed readings associated with unfavorable 6-month outcomes.114 NPi has been studied as a triage tool to predict the need for intervention in adults.115 In a prospective study of ICP-monitored children, NPi readings predicted ICP greater than 20 mmHg.32
Conflict of interest statement: This study was funded by the University of Texas Southwestern Department of Neurosurgery, and the University of Texas Southwestern Department of Nursing. D.W.M.O., V.A., and S.E.S. have received research support from NeurOptics, Inc.