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Observational Study
. 2019 May 2;23(1):155.
doi: 10.1186/s13054-019-2436-3.

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

Fritz-Patrick Jahns  1 , John Paul Miroz  2 , Mahmoud Messerer  3 , Roy T Daniel  3 , Fabio Silvio Taccone  4 , Philippe Eckert  1 , Mauro Oddo  5   6
Affiliations
Observational Study

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

Fritz-Patrick Jahns et al. Crit Care. .

Abstract

Background: Elevated intracranial pressure (ICP) is frequent after traumatic brain injury (TBI) and may cause abnormal pupillary reactivity, which in turn is associated with a worse prognosis. Using automated infrared pupillometry, we examined the relationship between the Neurological Pupil index (NPi) and invasive ICP in patients with severe TBI.

Methods: This was an observational cohort of consecutive subjects with severe TBI (Glasgow Coma Scale [GCS] < 9 with abnormal lesions on head CT) who underwent parenchymal ICP monitoring and repeated NPi assessment with the NPi-200® pupillometer. We examined NPi trends over time (four consecutive measurements over intervals of 6 h) prior to sustained elevated ICP > 20 mmHg. We further analyzed the relationship of cumulative abnormal NPi burden (%NPi values < 3 during total ICP monitoring time) with intracranial hypertension (ICHT)-categorized as refractory (ICHT-r; requiring surgical decompression) vs. non-refractory (ICHT-nr; responsive to medical therapy)-and with the 6-month Glasgow Outcome Score (GOS).

Results: A total of 54 patients were studied (mean age 54 ± 21 years, 74% with focal injuries on CT), of whom 32 (59%) had ICHT. Among subjects with ICHT, episodes of sustained elevated ICP (n = 43, 172 matched ICP-NPi samples; baseline ICP [T- 6 h] 14 ± 5 mmHg vs. ICPmax [T0 h] 30 ± 9 mmHg) were associated with a concomitant decrease of the NPi (baseline 4.2 ± 0.5 vs. 2.8 ± 1.6, p < 0.0001 ANOVA for repeated measures). Abnormal NPi values were more frequent in patients with ICHT-r (n = 17; 38 [3-96]% of monitored time vs. 1 [0-9]% in patients with ICHT-nr [n = 15] and 0.5 [0-10]% in those without ICHT [n = 22]; p = 0.007) and were associated with an unfavorable 6-month outcome (15 [1-80]% in GOS 1-3 vs. 0 [0-7]% in GOS 4-5 patients; p = 0.002).

Conclusions: In a selected cohort of severe TBI patients with abnormal head CT lesions and predominantly focal cerebral injury, elevated ICP episodes correlated with a concomitant decrease of NPi. Sustained abnormal NPi was in turn associated with a more complicated ICP course and worse outcome.

Keywords: Intracranial hypertension; Intracranial pressure; Neurological Pupil index; Outcome; Prognosis; Pupillary reactivity; Pupillometry; Traumatic brain injury.

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Conflict of interest statement

Ethics approval and consent to participate

The study was approved by the ethical committee of the University of Lausanne, with a waiver of consent provided, given the retrospective observational design.

Consent for publication

Not applicable.

Competing interests

Mauro Oddo has received speaker honoraria from Neuroptics®. All the remaining authors declare that they have no competing interest related to this study. The device manufacturer (Neuroptics, Laguna Hills, CA, USA) did not provide any financial support for the study and had no role in the study design, data collection, analysis and interpretation, or writing of the report.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Study flow chart
Fig. 2
Fig. 2
Trends over time of the Neurological Pupil index (NPi) during episodes of sustained elevated intracranial pressure (ICP). Line graphs illustrating trends over time of the NPi (blue line) during 43 episodes of elevated ICP (gray line). Data are mean ± standard deviation of a total of 172 paired ICP-NPi measurements; **p < 0.001 for pairwise comparisons of baseline ICP and NPi values (6 h previous to ICP max [red arrow]) with Ti (≈ − 4 h), Tii (≈ − 2 h), ICP max, and NPi min, respectively (time 0)
Fig. 3
Fig. 3
Trends over time of the Neurological Pupil index (NPi) during elevated intracranial pressure (ICP) treated with osmotherapy (mannitol or hypertonic saline bolus). Line graphs illustrating trends over time of the NPi (blue line) during 15 episodes of elevated ICP (gray line). Data are mean ± standard deviation of a total of 50 paired ICP-NPi measurements; **p < 0.001 for pairwise comparisons of baseline ICP and NPi values (start of osmotherapy [red arrow]) with Ti (≈ − 4 h), Tii (≈ − 2 h), ICP min, and NPi max, respectively (time 0)
Fig. 4
Fig. 4
Patient distribution of abnormal vs. normal NPi across the different Glasgow Outcome Score (GOS) categories. Histograms showing that the proportion of patients with abnormal NPi was higher in patients with GOS 1 and GOS 3, as compared to patients with GOS 4 and 5
See this image and copyright information in PMC

References

    1. Maas AIR, Menon DK, Adelson PD, Andelic N, Bell MJ, Belli A, Bragge P, Brazinova A, Buki A, Chesnut RM, et al. Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research. Lancet Neurol. 2017;16(12):987–1048. doi: 10.1016/S1474-4422(17)30371-X. - DOI - PubMed
    1. Cnossen MC, Huijben JA, van der Jagt M, Volovici V, van Essen T, Polinder S, Nelson D, Ercole A, Stocchetti N, Citerio G, et al. Variation in monitoring and treatment policies for intracranial hypertension in traumatic brain injury: a survey in 66 neurotrauma centers participating in the CENTER-TBI study. Crit Care. 2017;21(1):233. doi: 10.1186/s13054-017-1816-9. - DOI - PMC - PubMed
    1. Sharshar T, Citerio G, Andrews PJ, Chieregato A, Latronico N, Menon DK, Puybasset L, Sandroni C, Stevens RD. Neurological examination of critically ill patients: a pragmatic approach. Report of an ESICM expert panel. Intensive Care Med. 2014;40(4):484–495. doi: 10.1007/s00134-014-3214-y. - DOI - PubMed
    1. Chen JW, Gombart ZJ, Rogers S, Gardiner SK, Cecil S, Bullock RM. Pupillary reactivity as an early indicator of increased intracranial pressure: the introduction of the Neurological Pupil index. Surg Neurol Int. 2011;2:82. doi: 10.4103/2152-7806.82248. - DOI - PMC - PubMed
    1. Chen JW, Vakil-Gilani K, Williamson KL, Cecil S. Infrared pupillometry, the Neurological Pupil index and unilateral pupillary dilation after traumatic brain injury: implications for treatment paradigms. Springerplus. 2014;3:548. doi: 10.1186/2193-1801-3-548. - DOI - PMC - PubMed

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