Prognostication in Acute Neurological Emergencies

Abstract

Background: For patients with acute, serious neurological conditions presenting to the emergency department (ED), prognostication is typically based on clinical experience, scoring systems and patient co-morbidities. Because estimating a poor prognosis influences caregiver decisions to withdraw life-sustaining therapy, we investigated the consistency of prognostication across a spectrum of neurology physicians.

Methods: Five acute neurological presentations (2 with large hemispheric infarction; 1 with brainstem infarction, 1 with lobar hemorrhage, and 1 with hypoxic-ischemic encephalopathy) were selected for a department-wide prognostication simulation exercise. All had presented to our tertiary care hospital's ED, where a poor outcome was predicted by the ED neurology team within 24 hours of onset. Relevant clinical, laboratory and imaging data available before ED prognostication were presented on a web-based platform to 120 providers blinded to the actual outcome. The provider was requested to rank-order, from most to least likely, the predicted 90-day modified Rankin Scale (mRS) score. To determine the accuracy of individual outcome predictions we compared the patient's the actual 90-day mRS score to highest ranked predicted mRS score. Additionally, the group's "weighted" outcomes, accounting for the entire spectrum of mRS scores ranked by all respondents, were compared to the actual outcome for each case. Consistency was compared between pre-specified provider roles: neurology trainees versus faculty; non-vascular versus vascular faculty.

Results: Responses ranged from 106-110 per case. Individual predictions were highly variable, with predictions matching the actual mRS scores in as low as 2% of respondents in one case and 95% in another case. However, as a group, the weighted outcome matched the actual mRS score in 3 of 5 cases (60%). There was no significant difference between subgroups based on expertise (stroke/neurocritical care versus other) or experience (faculty versus trainee) in 4 of 5 cases.

Conclusion: Acute neuro-prognostication is highly variable and often inaccurate among neurology providers. Significant differences are not attributable to experience or subspecialty expertise. The mean outcome prediction from group of providers ("the wisdom of the crowd") may be superior to that of individual providers.

Keywords: Brain injury; Neurological emergencies; Neuroprognostication; Outcome prediction.

Figure 1:

(A) Case 1: brain MRI with diffusion restriction in the pons and medulla (left); CTA of the head and neck with left vertebral dissection and basilar thrombus (right). (B) Case 2: brain MRI with FLAIR abnormalities in the cerebellar vermis (left); brain MRI with FLAIR abnormalities in the bilateral globus pallidus and caudate nuclei (right). (C) Case 3: brain MRI with large left MCA infarct on DWI (left); CTA with left internal carotid artery dissection (right). (D) Case 4: head CT with 70 cc lobar hemorrhage with extension into the subarachnoid space (left) and 11 mm midline shift (right). (E) Case 5: brain MRI with large infarct in left MCA territory (left); head CTA with proximal left MCA occlusion (right). Abbreviations: MRI, magnetic resonance imaging; CT, computerized tomography; CTA, computerized tomography angiogram; FLAIR, Fluid-attenuated inversion recovery; DWI, diffusion weighted imaging; MCA, middle cerebral artery.

Figure 2:

Left, Weighted outcome of modified Rankin scale (mRS) in Cases 1 through 5 (A thru E, respectively) with the arrow corresponding to the actual 90-day mRS score. Right, Distribution of responses by individual rank.