The Full Outline of UnResponsiveness (FOUR) Score and Its Use in Outcome Prediction: A Scoping Systematic Review of the Adult Literature

Abstract

Background: The Full Outline of UnResponsivness (FOUR) score is a neurological assessment score. Its theoretical benefit over preexisting scores is its evaluation of brainstem reflexes and respiratory pattern which may allow better assessment of patients with severe neurologic impairment.

Objective: Our goal was to perform a scoping systematic review on the available literature for FOUR score and outcome prediction in critically ill patients. The primary outcome of interest was patient global outcome, as assessed by any of: mortality, modified Rankin Score, Glasgow Outcome Score, or any other functional or neuropsychiatric outcome. Information on interobserver reliability was also extracted.

Methods: MEDLINE and five other databases were searched. Inclusion criteria were: humans, adults, and children; prospective randomized controlled trial; prospective cohort, cohort/control, case series, prospective, and retrospective studies. Two reviewers independently screened the results. Full texts for citations passing this initial screen were obtained. Inclusion and exclusion criteria were applied to each article to obtain final articles for review. Results on adult populations are presented here. Data are reported following the preferred reporting items for systematic reviews and meta-analyses guidelines.

Results: The initial search yielded 1709 citations. Of those used, 49 were based on adult and 6 on pediatric populations. All but 8 retrospective adult studies were performed prospectively. Patient categories included traumatic brain injury, intraventricular hemorrhage, intracerebral hemorrhage, subarachnoid hemorrhage, ischemic stroke, general/combined neurology and neurosurgery, post-cardiac arrest, medicine/general critical illness, and patients in the emergency department. A total of 9092 adult patients were studied. Fourteen studies demonstrated good interobserver reliability of the FOUR score. Nine studies demonstrated prognostic value of the FOUR score in predicting mortality and functional outcomes. Thirty-two studies demonstrated equivalency or superiority of the FOUR score compared to Glasgow Coma Score in prediction of mortality and functional outcomes.

Conclusions: The FOUR score has been shown to be a useful outcome predictor in many patients with depressed level of consciousness. It displays good inter-rater reliability among physicians and nurses.

Keywords: Clinical scoring; Critical illness; FOUR score; Neurological illness; Prognosis.