Characteristics of Patients with an Abnormal Glasgow Coma Scale Score in the Prehospital Setting

OBJECTIVE This cross-sectional study describes the characteristics of patients with an abnormal Glasgow Coma Scale (GCS) in the prehospital setting. METHODS We reviewed existing prehospital care reports (PCRs) in the San Mateo County, California, emergency medical services (EMS) database from January 1 to December 31, 2007. Adults age 18 or greater with a documented GCS fit inclusion criteria. We excluded single and multisystem trauma patients, as well as patients in cardiac arrest, respiratory arrest, or listed as deceased from the study. We classified the remaining patients as a normal GCS of 15 or abnormal (defined as less than 15 at any time during paramedic contact), and then further sub-classified into mild (GCS 13-14), moderate (GCS 9-12) or severe (GCS 3-8). RESULTS Of the 12,235 unique prehospital care record in the database, 9,044 (73.9%) met inclusion criteria, comprised of 2,404 (26.6%) abnormal GCS patients and 6,640 (73.4%) normal GCS patients. In the abnormal GCS category, we classified 1,361 (56.6%) patients as mild, 628 (26.1%) as moderate, and 415 (17.3%) as severe. Where sex was recorded, we identified 1,214 (50.5%) abnormal GCS patients and 2,904 (43.7%) normal GCS patients as male. Mean age was 65.6 years in the abnormal GCS group and 61.4 in the normal GCS group (p<0.0001). Abnormal GCS patients were more likely to have a history of conditions known to be associated, such as alcohol abuse (odds ratio [OR] 2.3, 95% confidence interval [CI]=2.75-3.00), diabetes (OR 1.34, 95% CI=1.17-1.54), substance abuse (OR 1.6, CI=1.09-2.3), stroke/transient ischemic attack (OR 2.0, CI=1.64-2.5), and seizures (OR 3.0, CI=1.64-2.5). Paramedics established intravenous (IV) access on 1,821 (75.7%, OR 1.94, CI=1.74-2.2) abnormal GCS patients and administered medications to 777 (32.3%, OR 1.01, CI=0.92-1.12). Compared to patients with normal GCS, patients with a mildly abnormal GCS were less likely to receive medications (OR 0.61, CI=0.53-0.70) while those with a moderately or severely abnormal GCS were more likely (OR 1.27, CI=1.07-1.50 and OR 2.86, CI=2.34-3.49, respectively). Of the normal GCS patients, 4,097 (61.7%) received an IV and 2,125 (32.0%) received medications by any route. CONCLUSION Twenty-seven percent of all prehospital patients in our study presented with an abnormal GCS. Prehospital patients with an abnormal GCS are more likely to be male, slightly older, and have higher rates of history of alcohol use or seizure. This group of patients had a higher rate of IV placement. Patients with a mildly abnormal GCS were less likely to receive medications while those with a moderately or severely abnormal GCS were more likely.