GLASGOW COMA SCALE SCORE IN THE EVALUATION OF OUTCOME IN THE INTENSIVE-CARE UNIT - FINDINGS FROM THE ACUTE PHYSIOLOGY AND CHRONIC HEALTH EVALUATION-III STUDY

Objective: To investigate the ability of the Glasgow Coma Scale score to predict hospital mortality rate for adult medical-surgical intensiv e care unit (ICU) patients without trauma. Design: A prospective cohor t analysis of adult medical-surgical patients from a nationally repres entative sample of 40 U.S. hospitals. Patients: 15,973 consecutive, no ntraumatic ICU admissions and a comparison group of 687 head trauma ad missions. Interventions: None. Measurements and Main Results: Patients ' gender, age, treatment location before ICU admission, comorbidities, admission diagnosis, daily physiologic measurements, Glasgow Coma Sca le score, Acute Physiology and Chronic Health Evaluation (APACHE III(T M)) score, subsequent hospital mortality rate, and unit-specific sedat ion practices were noted. Hospital mortality rates were stratified by the first ICU day Glasgow Coma Scale score for all admissions. The rel ationship between the Glasgow Coma Scale score and outcome for two hig h mortality medical diagnoses (post-cardiac arrest and sepsis) were al so examined and compared to the relationship found in patients with he ad trauma. The Glasgow Coma Scale score on ICU admission had a highly significant (r2=.922, p < .0001) but nonlinear relationship with subse quent outcome in ICU patients without trauma. Discrimination of patien ts into high- or low-risk prognostic groups was good, but discriminati on in the intermediate levels (Glasgow Coma Scale score of 7 to 11) wa s reduced. This relationship varied within the operative and nonoperat ive groups, and also within different disease categories, various age groups, and certain ranges of the Glasgow Coma Scale score. A reduced initial Glasgow Coma Scale score associated with sepsis was a combinat ion of factors associated with a higher mortality rate than that found in patients with head trauma. The proportion of patients who could no t be assigned a Glasgow Coma Scale score because of sedation/paralysis varied widely across ICUs. The overall predictive capability of the A PACHE III Prognostic Scoring System was improved by incorporating the Glasgow Coma Scale score. Conclusions: We demonstrated the prognostic importance of admission levels of consciousness as measured by the Gla sgow Coma Scale score on ICU and hospital mortality rates. We conclude d that the Glasgow Coma Scale score may be used to stratify and predic t mortality risk in general intensive care patients, but lack of sensi tivity in the intermediate range of Glasgow Coma Scale Score should be noted. Ideally, the Glasgow Coma Scale score should also be applied i n the context of other physiologic information and the patient's speci fic diagnosis. Variation in the use of sedatives in different ICUs mea ns that imputing or substituting a value other than normal for an unob tainable Glasgow Coma Scale score may introduce a substantial treatmen t bias into subsequent outcome predictions.