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Correlation Between Quantitative Pupillometry and Other Markers for Neuroprognostication of Comatose Patients After
Sarah Benghanem1,2, Jan Novy1, Alain Cariou2
1Department of Clinical Neurosciences, Lausanne University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland.
Objectives:
The prognostic role of quantitative pupillometry in comatose patients after cardiac arrest (CA) has been recently described, but data on quantitative pupillary light reflex (qPLR) are limited, especially in a multimodal approach and regarding good outcome. We assessed qPLR correlations with clinical features, electroencephalogram (EEG), somatosensory evoked potentials (SSEPs), and neuron-specific enolase (NSE), as well as qPLR prognostic values toward poor and good outcomes.
Design, Settings, And Patients:
Bicentric study (Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland and Cochin Hospital, Paris, France), analyzing prospective registries of comatose adults with pupillometry parameters obtained during the first 48-72 hours after CA. Neurological Pupil index (NPi), lowest (minimum qPLR), and highest values (maximum qPLR) of qPLR were collected. Predictive performances in terms of Cerebral Performance Categories (CPCs) level at 3 months (good outcome: CPC 1-2) were calculated.
Interventions:
None.
Measurements And Main Results:
Between 2020 and 2024, 442 patients were included. Minimum and maximum qPLRs were significantly lower in case of early myoclonus ( p < 0.001), bilateral N20 SSEP absence ( p < 0.001), unreactive EEG ( p < 0.001), and epileptiform EEG ( p = 0.03 and 0.05). qPLR was also significantly lower with suppressed EEG, compared with discontinuous and continuous background ( p < 0.001). Serum NSE level at 48 hours was significantly correlated with minimum (Spearman Rho = -0.283; p < 0.001) and maximum qPLRs ( R = -0.444; p < 0.001). Minimum qPLR less than 2% (96.4% specificity, 23.6% sensitivity), maximum qPLR less than 13% (96.4% specificity, 19.0% sensitivity), and NPi less than or equal to 2 (99% specificity, 34% sensitivity) robustly correlated with poor outcome. Notably, qualitative PLR had higher sensitivity than minimum and maximum qPLRs (38.9 vs. 23.6 and 19.0%, respectively; p < 0.001) with comparable specificity. A minimum qPLR greater than 9.5% (83.2% specificity, 31.1% sensitivity) and a maximum qPLR greater than 25.5% (62.2% specificity, 65.5% sensitivity) correlated with good outcome.
Conclusions:
In comatose patients after CA, qPLR is tightly correlated with other prognostic markers; low qPLR and NPi less than or equal to 2 appeared highly specific for poor outcome, but performances do not exceed that of clinical PLR. Finally, high qPLR remained limited in predicting a good outcome.
