The Effect of Ambient Light Conditions on Quantitative Pupillometry

Ong, Charlene; Hutch, Meghan R.; Smirnakis, Stelios M.

doi:10.1007/s12028-018-0607-8

Cited by 39 publications

(29 citation statements)

References 17 publications

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“…It was shown by Delfino et al that infused propofol at 100 μg/kg/min (= 6 mg/kg/h) resulted in bispectral index (BIS) monitoring values of approximately 42 [30], and indeed, at this infusion rate, propofol has no effect on the NPi (while it significantly reduced pupil size and percentage constriction) [31]. Finally, it is worth noting that the NPi value is adjusted to individual resting pupil size [32]. In summary, we may reasonably conclude that the combination of propofol and opioids was unlikely to produce the changes of the NPi observed during ICP episodes.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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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 [T 0 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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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“…Furthermore, pupillometry measurements were performed by an experienced research ICU physician or nurse, thereby guaranteeing data reliability and quality, and the pupillometry data were blinded to clinicians involved in patient care. We did not adjust for ambient light conditions, which may at least in part affect q-PLR [44]. However, the pupillometer used in this study (AlgiScan® device) has a black rubber that completely covers the eye, thereby ensuring homogeneous dark conditions during pupillary constriction measurements.…”

Section: Study Limitationsmentioning

confidence: 99%

Neuromonitoring of delirium with quantitative pupillometry in sedated mechanically ventilated critically ill patients

et al. 2020

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Background: Intensive care unit (ICU) delirium is a frequent secondary neurological complication in critically ill patients undergoing prolonged mechanical ventilation. Quantitative pupillometry is an emerging modality for the neuromonitoring of primary acute brain injury, but its potential utility in patients at risk of ICU delirium is unknown. Methods: This was an observational cohort study of medical-surgical ICU patients, without acute or known primary brain injury, who underwent sedation and mechanical ventilation for at least 48 h. Starting at day 3, automated infrared pupillometry-blinded to ICU caregivers-was used for repeated measurement of the pupillary function, including quantitative pupillary light reflex (q-PLR, expressed as % pupil constriction to a standardized light stimulus) and constriction velocity (CV, mm/s). The relationship between delirium, using the CAM-ICU score, and quantitative pupillary variables was examined. Results: A total of 59/100 patients had ICU delirium, diagnosed at a median 8 (5-13) days from admission. Compared to non-delirious patients, subjects with ICU delirium had lower values of q-PLR (25 [19-31] vs. 20 [15-28] %) and CV (2.5 [1.7-2.8] vs. 1.7 [1.4-2.4] mm/s) at day 3, and at all additional time-points tested (p < 0.05). After adjusting for the SOFA score and the cumulative dose of analgesia and sedation, lower q-PLR was associated with an increased risk of ICU delirium (OR 1.057 [1.007-1.113] at day 3; p = 0.03). Conclusions: Sustained abnormalities of quantitative pupillary variables at the early ICU phase correlate with delirium and precede clinical diagnosis by a median 5 days. These findings suggest a potential utility of quantitative pupillometry in sedated mechanically ventilated ICU patients at high risk of delirium.

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“…Although a previous study showed that the use of these medications within therapeutic doses does not signi cantly suppress the PLR [38], we cannot exclude the possibility that other medications such as propofol may have affected the PLR [39]. Third, we did not analyze confounders such as underlying pathology of the retina or optic nerve as well as the in uence of ambient lights on the PLR [40].…”

Section: Discussionmentioning

confidence: 99%

Quantitative Assessments of Pupillary Light Reflexes in Hospital-Onset Unconsciousness

Lee

Choi

Park

et al. 2020

Preprint

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BackgroundPatients who develop hospital-onset unconsciousness should be promptly managed in order to avoid clinical deterioration. Pupillary examination through pupillary light reflex is the mainstay method in the initial evaluation of unconscious patients, but the current method of light shedding and subjective description often shows poor reliability. The objective of this study is to explore whether a quantitative measurement of pupillary light reflexes is useful in detecting brain herniation syndrome and predicting neurological outcomes in non-neurological patients who developed hospital-onset unconsciousness.MethodsThis was a registry-based observational study on patients who activated the neurological rapid response team at Asan Medical Center (Seoul, Korea). Hospital-onset unconsciousness was defined as a newly developed stupor or comatose state during admission. Demographics, comorbidities, pupillometry parameters including Neurological Pupil index, brain herniation syndrome, in-hospital mortality, and modified Rankin Scale at 3-months were analyzed.ResultsIn 214 consecutive patients with hospital-onset unconsciousness, 37 (17%) had brain herniation syndrome. The optimal cut-off value of Neurological Pupil index for detecting brain herniation syndrome was < 1.6 (specificity, 91% [95% confidence interval (CI) = 86−95]; sensitivity, 49% [95% CI = 32−66]). The in-hospital mortality rate was 28% (59/214); the Neurological Pupil index was negatively associated with in-hospital mortality after adjustments for the presence of brain herniation syndrome (adjusted odds ratio = 0.77, 95% CI = 0.62–0.96). Poor neurological outcomes (modified Rankin Scale ≥ 4) at 3 months was observed in 76% (152/201) of the patients; the Neurological Pupil index was negatively associated with poor neurological outcomes after adjustments for clinical variables (adjusted odds ratio = 0.67, 95% CI = 0.49–0.90). ConclusionsQuantitative measurements of pupillary light reflexes may be useful for early detection of potentially life-threatening neurological conditions in patients with hospital-onset unconsciousness.

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The Effect of Ambient Light Conditions on Quantitative Pupillometry

Cited by 39 publications

References 17 publications

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

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

Neuromonitoring of delirium with quantitative pupillometry in sedated mechanically ventilated critically ill patients

Quantitative Assessments of Pupillary Light Reflexes in Hospital-Onset Unconsciousness

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