Automated Pupillometry as a Triage and Assessment Tool in Patients with Traumatic Brain Injury

doi:10.1016/j.wneu.2020.09.152

World Neurosurgery

Volume 145, January 2021, Pages e163-e169

https://doi.org/10.1016/j.wneu.2020.09.152 Get rights and content

Objective

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in young adults. Automated infrared pupillometry (AIP) has shown promising results in predicting neural damage in aneurysmal subarachnoid hemorrhage and ischemic stroke. We aimed to explore potential uses of AIP in triaging patients with TBI. We hypothesized that a brain injury severe enough to require an intervention would show Neurologic Pupil Index (NPI) changes.

Methods

We conducted a prospective pilot study at a level-1 trauma center between November 2019 and February 2020. AIP readings of consecutive patients seen in the emergency department with blunt TBI and abnormal imaging findings on computed tomography were recorded by the assessing neurosurgery resident. The relationship between NPI and surgical intervention was studied.

Results

Thirty-six patients were enrolled, 9 of whom received an intervention. NPI was dichotomized into normal (≥3) versus abnormal (<3) and was predictive of intervention (Fisher exact test; P < 0.0001). Six of the 9 patients had a Glasgow Coma Scale (GCS) score ≤8 and imaging signs of increased intracranial pressure (ICP) and underwent craniectomy (n = 4) or ICP monitor placement (n = 2) and had an abnormal NPI. Three patients underwent ICP monitor placement for GCS score ≤8 in accordance with TBI guidelines despite minimal imaging findings and had a normal NPI. The GCS score of these patients improved within 24 hours, requiring ICP monitor removal. NPI was normal in all patients who did not require intervention.

Conclusions

AIP could be useful in triaging comatose patients after blunt TBI. An NPI ≥3 may be reassuring in patients with no signs of mass effect or increased ICP.

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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Prediction for the prognosis of diffuse axonal injury using automated pupillometry
2024, Clinical Neurology and Neurosurgery
Previous studies have reported various predictive indicators of diffuse axonal injury (DAI), but no consensus has not been reached. Although the efficiency of automated pupillometry in patients with consciousness disorder has been widely reported, there are few reports of its use in patients with DAI. This study aimed to investigate the significance of pupillary findings in predicting the prognosis of DAI.
We included patients admitted to our center with a diagnosis of DAI from June 1, 2021 to June 30, 2022. Pupillary findings in both eyes were quantitatively measured by automated pupillometry every 2 hours after admission. We statistically examined the correlations between automated pupillometry parameters, the patients’ characteristics, and outcomes such as the Glasgow Outcome Scale Extended (GOSE) after 6 months from injury, the time to follow command, and so on.
Among 22 patients included in this study, five had oculomotor nerve palsy. Oculomotor nerve palsy was correlated with all outcomes, whereas Marshall computed tomography (CT) classification, Injury severity score (ISS) and DAI grade were correlated with few outcomes. Some of the automated pupillometry parameters were significantly correlated with GOSE at 6 months after injury, and many during the first 24 hours of measurement were correlated with the time to follow command. Most of these results were not affected by adjustment using sedation period, ISS or Marshall CT classification. A subgroup analysis of patients without oculomotor nerve palsy revealed that many of the automated pupillometry parameters during the first 24 hours of measurement were significantly correlated with most of the outcomes. The cutoff values that differentiated a good prognosis (GOSE 5–8) from a poor prognosis (GOSE 1–4) were constriction velocity (CV) 1.43 (AUC = 0.81(0.62–1), p = 0.037) and maximum constriction velocity (MCV) 2.345 (AUC = 0.78 (0.58–0.98), p = 0.04). The cutoff values that differentiated the time to follow command into within 7 days and over 8 days were percentage of constriction 8 (AUC = 0.89 (0.68–1), p = 0.011), CV 0.63 (AUC = 0.92 (0.78–1), p = 0.013), MCV 0.855 (AUC = 0.9 (0.74–1), p = 0.017) and average dilation velocity 0.175 (AUC = 0.95 (0.86–1), p = 0.018).
The present results indicate that pupillary findings in DAI are a strong predictive indicator of the prognosis, and that quantitative measurement of them using automated pupillometry could facilitate enhanced prediction for the prognosis of DAI.
Quantitative Pupillometry Values are Remarkably Similar Before and After Neuroimaging
2023, Journal of Radiology Nursing
Automated assessment of the pupillary light reflex (PLR) is becoming more mainstream, yet there is much to learn about the correlations between automated PLR metrics and standard practice. This study explores the feasibility and potential value of assessing PLR using quantitative pupillometry (QP) in patients with critical neurologic illness before and after neuroimaging.
PLR assessments using QP were taken within 30 minutes before and 30 minutes after computerized tomography (CT) or magnetic resonance imaging (MRI) on patients in the neuroscience intensive care unit.
Fifty patients were enrolled. The neurological pupil index (NPi®) was 3.98 (1.12) in the right eye and 3.96 (1.0) in the left eye before imaging, and 4.13 (1.08) in the right eye and 4.08 (0.93) in the left eye after imaging. Although the before and after difference in the left eye was a statistically significant (p < .01), these differences were not clinically relevant. Roughly 8% of subjects showed improvement in NPi scores from abnormal (<3.0) before imaging, to normal (>3.0) after.
Obtaining QP readings before and after neuroimaging is feasible and safe. Yet, these data suggest it may not be necessary to obtain pre-QP and post-QP readings when the NPi is normal before CT or MRI.
Auditing the status of prioritization of nursing actions in the trauma emergency department
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Patient assessment is considered as one of the key actions of nurses to provide professional services. Prioritizing the care needs based on the assessment could save patients' lives. Nurses should be able to prioritize patients' care needs and then, based on this prioritization, plan for patient life-threatening situations one after the other. The aim of this study was to audit the status of prioritization of nursing care for trauma patients in the trauma emergency department of Kowsar Hospital in Sanandaj.
This study was a quasi-experimental study (pre- and post-training) conducted using simple random sampling during the February to June 2021, in the emergency department of Kowsar Hospital in Sanandaj. The data collection tool was a standardized checklist for prioritizing nursing care, which contained a total of 53 items. At the beginning of the study, 64 nurses (32 in the experimental group and 32 in the control group) entered the study and the experimental group was evaluated based on a standardized prioritization checklist. Then, the data were collected and after statistical analysis, based on the obtained results and examining the weaknesses, the intervention group nurses participated in an educational course for one month. The checklist assessment was performed again and the results were compared with the results of the first assessment (before the intervention).
The number of items requiring training in the experimental group before the intervention was 258 cases which decreased to 53 cases after training and this decrease was statistically significant (p < 0.05). However, in the control group, the number of measures requiring training in the first stage was 220 cases, which in the second stage of assessment fell to 213, but this decrease was not statistically significant (p > 0.05).
By auditing the status of nursing care prioritization in the trauma emergency department and providing training related to focusing on the identified weaknesses, nurses' skills to prioritize patients' care needs as well as the quality of nursing care delivery increased.
Pilot Study of Neurologic Pupil Index as A Predictor of External Ventricular Drain Clamp Trial Failure After Subarachnoid Hemorrhage
2022, World Neurosurgery
Citation 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.
External ventricular drains (EVDs) provide a temporary egress for cerebrospinal fluid (CSF) in patients with symptomatic hydrocephalus following aneurysmal subarachnoid hemorrhage. Before EVD removal, a wean trial, which involves clamping the EVD, is typically attempted to ensure that CSF self-regulation is achieved. Automated infrared pupillometry (AIP) has been shown to detect early neurologic decline. We sought to explore the use of AIP to detect early EVD clamping trial failure.
This prospective observational pilot study enrolled aneurysmal subarachnoid hemorrhage patients before an EVD clamp trial. On initiating the clamp trial, nurses included hourly AIP assessment in documentation. Clamp trial outcome was based on neurologic examination and neuroimaging. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) models were constructed to explore computed tomography (CT) versus AIP as predictors of clamp trial outcome.
Among the 30 subjects enrolled, there were 38 clamping trials and 22 successful EVD removals. CT scan as a predictor of clamp trial was found to have a sensitivity of 68.8% and specificity of 89.5% (PPV = 84.6%, NPV = 77.3%). AIP assessment as a predictor of wean trial outcome was found to have a sensitivity of 58.3% and specificity of 100% (PPV = 100%, NPV = 63.2%).
The pilot study data support that Neurological Pupil index <3 is a potential indicator of early clamp trial failure, but a CT scan has a higher sensitivity and NPV for predicting successful EVD removal. This finding suggests the benefits of including AIP assessments during clamping trials.
Inter-device reliability of the NPi-200 and NPi-300 pupillometers
2022, Journal of Clinical Neuroscience
Citation 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.
The pupillary evaluation is an essential part of the neurological examination. Research suggests that the traditional examination of the pupil with a handheld flashlight has limited interrater reliability. Automated pupillometers were developed to provide an objective scoring of various pupillary parameters. The NPi-200 pupillometer is used for quantitative pupillary examinations, the NPi-300 was launched in July 2021 with enhanced features. The purpose of this study is to compare results from the NPi-200 to the NPi-300 to ensure that data are translatable across both platforms. This study examines the inter-device reliability of the NPi-200 compared to the NPi-300 in two cohorts: 20 patients at risk for cerebral edema and 50 healthy controls. Paired assessments of the devices were made from all participants. Each assessment included bilateral PLR readings within a 5-minute interval. Data showed high agreement between the two devices for the Neurological Pupil Index (NPi) reading (k = 0.94; CI: 0.91–0.99) and for pupil diameter assessment (k = 0.91; CI: 0.87–0.96). There is a very high level of agreement between the NPi-200 and NPi-300 among healthy controls and critically ill patients. Clinicians and researchers can interpret the results from either device equally.
Multimodal Neurologic Monitoring in Children With Acute Brain Injury
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Citation 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
Children with acute neurologic illness are at high risk of mortality and long-term neurologic disability. Severe traumatic brain injury, cardiac arrest, stroke, and central nervous system infection are often complicated by cerebral hypoxia, hypoperfusion, and edema, leading to secondary neurologic injury and worse outcome. Owing to the paucity of targeted neuroprotective therapies for these conditions, management emphasizes close physiologic monitoring and supportive care. In this review, we will discuss advanced neurologic monitoring strategies in pediatric acute neurologic illness, emphasizing the physiologic concepts underlying each tool. We will also highlight recent innovations including novel monitoring modalities, and the application of neurologic monitoring in critically ill patients at risk of developing neurologic sequelae.

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: 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.

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Original ArticleAutomated Pupillometry as a Triage and Assessment Tool in Patients with Traumatic Brain Injury

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Study Population

Results

Discussion

Conclusions

CRediT authorship contribution statement

Acknowledgments

Lancet

J Clin Neurosci

J Stroke Cerebrovasc Dis

World Neurosurgery

J Crit Care

Traumatic brain injuries

Nat Rev Dis Primers

Estimating the global incidence of traumatic brain injury

Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition

Neurosurgery

Glasgow Coma Scale motor score and pupillary reaction to predict six-month mortality in patients with traumatic brain injury: comparison of field and admission assessment

J Neurotrauma

Letter: Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition

Neurosurgery

Integrating quantitative pupillometry into regular care in a neurotrauma intensive care unit

J Neurosci Nurs

Interrater reliability of pupillary assessments

Neurocrit Care

Establishing normative data for pupillometer assessment in neuroscience intensive care: the "END-PANIC" registry

J Neurosci Nurs

Quantitative pupillometry for the monitoring of intracranial hypertension in patients with severe traumatic brain injury

Crit Care

Detection of delayed cerebral ischemia using objective pupillometry in patients with aneurysmal subarachnoid hemorrhage

J Neurosurg

Original Article
Automated Pupillometry as a Triage and Assessment Tool in Patients with Traumatic Brain Injury