Prediction of neurocritical care intensity through automated infrared pupillometry and transcranial doppler in blunt traumatic brain injury: the NOPE study

Abstract

Abstract Purpose This pilot study aimed to determine the capacity of automated infrared pupillometry (AIP) alone and in combination with transcranial doppler (TCD) on admission to rule out need for intense neuroAQ2 critical care (INCC) in severe traumatic brain injury (TBI). Methods In this observational pilot study clinicians performed AIP and TCD measurements on admission in blunt TBI patients with a Glasgow Coma Score (GCS) < 9 and/or motor score < 6. A Neurological Pupil index (NPi) < 3, Pulsatility Index (PI) > 1,4 or diastolic blood flow velocity (dV) of < 20 cm/s were used to rule out the need for INCC (exceeding the tier 0 Seattle Consensus Conference). The primary outcome was the negative likelihood ratio (nLR) of NPi < 3 alone or in combination with TCD to detect need for INCC. Results A total of 69 TBI patients were included from May 2019 to September 2020. Of those, 52/69 (75%) median age was 45 [28–67], median prehospital GCS of 7 [5–8], median Injury Severity Scale of 13.0 [6.5–25.5], median Marshall Score of 4 [3–5], the median Glasgow Outcome Scale at discharge was 3 [1–5]. NPi < 3 was an independent predictor of INCC. NPi demonstrated a nLR of 0,6 (95%CI 0.4–0.9; AUROC, 0.65, 95% CI 0.51–0.79), a combination of NPi and TCD showed a nLR of 0.6 (95% CI 0.4–1.0; AUROC 0.67 95% CI 0.52–0.83) to predict INCC. Conclusion This pilot study suggests a possible useful contribution of NPi to determine the need for INCC in severe blunt TBI patients on admission.