Association of the Verbal Component of the GCS With Mortality in Patients With Encephalopathy Who Are Not Undergoing Mechanical Ventilation

Abstract

Background and objectives: The utility of the Glasgow Coma Scale (GCS) in intubated patients is limited due to reliance on language function evaluation. The Full Outline of Unresponsiveness (FOUR) Score was designed to circumvent this shortcoming, instead adding evaluations of brainstem reflexes (FOUR B) and specific respiratory patterns (FOUR R). We aimed to determine whether the verbal component of the GCS (GCS V) among nonintubated patients with encephalopathy significantly contributes to mortality prediction and to assess GCS vs FOUR Score performance.

Methods: All prospectively consented patients ≥18 years of age admitted to the Internal Medicine service at Zambia's University Teaching Hospital from October 3, 2017, to May 21, 2018, with a GCS score ≤10 have undergone simultaneous GCS and FOUR Score assessments. The patients were not eligible for mechanical ventilatory support per local standards. Patients' demographics and clinical characteristics were presented as either percentage frequencies or numerical summaries of spread. The predictive power of the GCS without the Verbal component vs total GCS vs FOUR Score on mortality was estimated with the area under the receiver operating characteristic curve (AU ROC).

Results: Two hundred thirty-five patients (50% women, mean age 47.5 years) were enrolled. All patients were Black. Presumed etiology was CNS infection (64, 27%), stroke (63, 27%), systemic infection (39, 16.6%), and metabolic encephalopathy (3, 14.5%); 14.9% had unknown etiology. In-hospital mortality was 83%. AU ROC for GCS Eye + Motor score (0.662) vs total GCS score (0.641) vs total FOUR Score (0.657) did not differ. Odds ratio mortality for GCS score >6 vs ≤6 was 0.32 (95% confidence interval [CI] 0.14-0.72, p = 0.01); for FOUR Score >10 vs ≤10, it was 0.41 (95% CI 0.19-0.86, p = 0.02).

Discussion: Absence of a verbal component of GCS had no significant impact on the performance of the total GCS, and either GCS or FOUR Score is an acceptable scoring tool for mortality prediction in the resource-limited setting. These findings need further validation in the countries with readily available mechanical ventilatory support.

Classification of evidence: This study provides Class I evidence that the verbal component of the GCS does not significantly contribute to a total GCS score in mortality prediction among patients with encephalopathy who are not intubated.