92 No Yes Total 113 13 126 Table 1 Loss of consciousness and evolution of the patients in respect to the outcome (immediate hospital discharge, hospitalization and death) Immediate discharge Hospitalization Death 135 55 190 9 35 44 Total 257 103 360 Chi-square=76.542; DF =2; p=0.000 literature. The aim of this study was to evaluate whether loss of consciousness at the scene of an accident in patients with thoracic injuries classified as ≥2 according to the AIS has a different outcome compared to less severe injuries in respect to immediate hospital discharge, hospitalization, death and type of accident. Methods A prospective study was carried out at the Regional Trauma Center of São José do Rio Preto from 1 July 2004 to 30 June 2005 to identify patients with thoracic injuries according to the AIS. All patients with scores ≥2 were included in the study. The AIS is a consensus-derived, anatomically based system of grading injuries on a non- linear scale ranging from 1 (minor injury) to 6 (lethal injury) [10, 11]. Loss of consciousness at the scene of the accident before evaluation in the hospital emergency room was correlated with: immediate hospital discharge, hospi- talization and death. The evaluation of the loss of consciousness was made by trained emergency ambulance teams, specialists in this type of situation. Additionally, associations between the types of trauma and loss of Int J Emerg Med (2010) 3:91–95 consciousness were evaluated in respect to (1) car crashes, (2) motorbike crashes, (3) pedestrian-vehicle collisions, (4) falls, (5) bicycle accidents, (6) gunshot wounds, (7) stabbings, (8) fights, (9) burns, (10) impaling, (11) electric shock involving falls to the ground, (12) bites, (13) drowning with thoracic trauma, (14) suicide, (15) non- intentional injuries and (16) others. The injuries were evaluated using the ISS, TRISS and the Revised Trauma Score (RTS), but this was not the objective of the study. The chi-square, Fisher's exact and relative risk tests were utilized for statistical analysis with an alpha error greater than 5% (p < 0.05) considered statistically significant. Results A total of 365 patients classified with scores of ≥2 according to the AIS were evaluated. The ages of the patients varied from 13 to 89 years old (mean, 37.9 years). The number of men (291) was significantly greater than the number of women (74) (p < 0.0001). A total of 134 patients with penetrating thoracic injuries and 231 with blunt injuries were included in this study. A significantly higher number of patients who lost consciousness (35–33.9%) died compared to those who did not lose consciousness (9–3.5%, Fisher's exact test: p < 0.0001) where the relative risk (RR) of death when an individual lost consciousness was 9.7 (95% CI: 4.8–19.4). In respect to discharge from hospital, patients who lost consciousness were more commonly hospitalized (Fisher's exact test: p < 0.0001). Forty-seven patients arrived at the hospital with a systemic arterial pressure of 0 mmHg and 45 patients with a pressure of less than 90 mmHg. In relation to the respiration rate, 49 patients had a rate of 0 inspirations per minute and 8 patients less than 10 inspirations per minute. Table 2 Types of trauma associated with loss of consciousness Others: burns, impaling, electric shock, bites, drowning, suicide and non-intentional wounds Type of accident Car crash Motor crash Pedestrian-vehicle collisions Falls Bicycle accidents Gunshots Stabbings Fights Others Total 103 35 12 13 19 9 6 2 2 2 257 54 33 8 54 13 12 38 11 11 360 Loss of consciousness Without loss of consciousness Total p-value 89 45 21 73 22 18 40 13 13 0.001 0.9143 0.0017 0.3964 0.2233 0.6039 0.0001 0.762 0.3635 Relative risk 95% CI 1.5 (1.1 to 2.1) 0.9 (0.5 to 1.5) 2.3 (1.5 to 3.4) 0.8 (0.5 to 1.3) 1.4 (0.8 to 2.5) 1.1 (0.5 to 2.3) 0.1 (0.04 to 0.6) 0.3 (0.08 to 1.2) 0.5 (0.1 to 1.9)