AEM Early Access 09: The Hack's Impairment Index (HII) Score

Welcome to the ninth episode of AEM Early Access, a FOAMed podcast collaboration between the Academic Emergency Medicine Journal and Brown Emergency Medicine. Each month, we'll give you digital open access to an recent AEM Article or Article in Press, with an author interview podcast and suggested supportive educational materials for EM learners. This one is a mid-month bonus!

Find this podcast series on iTunes here.

A FOAM Collaboration: Academic Emergency Medicine Journal and Brown EM

A FOAM Collaboration: Academic Emergency Medicine Journal and Brown EM


Performance of the Hack’s Impairment Index Score: A Novel Tool to Assess Impairment from Alcohol in Emergency Department Patients Jason B. Hack, MD, Eric J. Goldlust, MD, Dennis Ferrante and Brian J. Zink, MD

(click on title for full text; open access through January 5, 2018)     

listen now: interview with lead author Dr. Jason Hack


Jason Hack, MD, FACEP, FACMT
Director, Division of Medical Toxicology. Brown University
Professor, Department of Emergency Medicine
Warren Alpert Medical School,
Brown University


Background: Over 35 million alcohol-impaired (AI) patients are cared for in emergency departments (EDs) annually. Emergency physicians are charged with ensuring AI patients’ safety by identifying resolution of alcohol induced impairment. The most common standard evaluation is an extemporized clinical examination, as ethanol levels are not reliable or predictive of clinical symptoms. There is no standard assessment of ED AI patients.

Objective: The objective was to evaluate a novel standardized ED assessment of alcohol impairment, Hack’s Impairment Index (HII score), in a busy urban ED.

Methods: A retrospective chart review was performed for all AI patients seen in our busy urban ED over 24 months. Trained nurses evaluated AI patients with both “usual” and HII score every 2 hours. Patients were stratified by frequency of visits for AI during this time: high (≥ 6), medium (2–5), and low (1). Within each category, comparisons were made between HII scores, measured ethanol levels, and usual nursing assessment of AI. Changes in HII scores over time were also evaluated. Results: A total of 8,074 visits from 3,219 unique patients were eligible for study, including 7,973 (98.7%) with ethanol levels, 5,061 (62.7%) with complete HII scores, and 3,646 (45.2%) with health care provider assessments. Correlations between HII scores and ethanol levels were poor (Pearson’s R2 = 0.09, 0.09, and 0.17 for high-, medium-, and low-frequency strata). HII scores were excellent at discriminating nursing assessment of AI, while ethanol levels were less effective. Omitting extrema, HII scores fell consistently an average 0.062 points per hour, throughout patients’ visits.

Conclusions: The HII score applied a quantitative, objective assessment of alcohol impairment. HII scores were superior to ethanol levels as an objective clinical measure of impairment. The HII declines in a reasonably predictable manner over time, with serial evaluations corresponding well with health care provider evaluations.


CORRECTIVE NOTE: Dr. Hack would like to note a correction in the podcast audio, in which he states the HII sections are scored 'up to five'; rather, there are five sections/tasks, with a score of zero to four in each. 


Further reading:

1.    Hack JB, Goldlust D, Ferrante D, Zink B.  The HII Score – A Novel Tool to Assess Impairment from Alcohol in Emergency Department Patients. Acad Emerg Med. 2017 Oct; 24(10):1193-1203.

2.   Hack JB, Goldlust EJ, Gibbs F, Zink B. The H-Impairment Index (HII): a standardized assessment of alcohol induced impairment in the emergency department. Am J Drug Alcohol Abuse 2014;40:111–7.

3.   Benoit JL, Hart KW, Soliman AA, et al. Developing a standardized measurement of alcohol intoxication. Am J Emerg Med 2017;35:725–30.

4.   Todd K, Berk WA, Welch RD, et al. Prospective analysis of mental status progression in ethanol-intoxicated patients. Am J Emerg Med 1992;10:271– 3. 5.    

5.   Galbraith S. Misdiagnosis and delayed diagnosis in traumatic intracranial haematoma. Br Med J 1976;1:1438– 9.