The H-Impairment Index (HII): a standardized assessment of alcohol-induced impairment in the Emergency Department

Emergency Departments (EDs) care for thousands of alcohol-intoxicated patients annually. No clinically relevant bedside measures currently exist to describe degree of impairment.

To assess a group of bedside tests ("Hack's Impairment Index [HII] score") that applies a numerical value to the degree of alcohol-induced impairment in ED patients.

A six-month retrospective review of HII score data was performed in a convenience sample of 293 intoxicated ED patients. Patients were scored 0-4 on five tasks, divided by the maximum score (20 if all tasks completed), every 2 hours; and classified by the number of visits: Low-frequency (1 visit); Medium-frequency (2 visits); High-frequency (≥3 visits). Correlations were assessed between HII score, healthcare provider judgment of intoxication, and measured alcohol levels.

Study patients had 513 visits; 236 were low-frequency, 26 middle-frequency and 31 high-frequency. Clinical assessment and HII score were strongly correlated (Spearman's rho = 0.82, p << 0.001); clinical assessment and alcohol level less strongly so (rho = 0.49, p << 0.001). Among low-frequency patients, HII score and alcohol level were weakly correlated (r = 0.324, p < 0.001), with no such correlation among high-frequency visitors (r = -0.04, p = 0.89). The mean decline between serial HII scores was 0.126 (95% CI: 0.098-0.154).

This pilot study shows the HII score can be performed at the bedside of alcohol-intoxicated patients. The HII declines in a reasonably predictable manner over time; and applies a quantitative, objective assessment of alcohol impairment.