METHODS

Data were obtained from the Los Angeles County Trauma database, which consists of case reports from six level I (five adult, one pediatric) and seven level II American College of Surgeons verified trauma centers. Patient data were entered into the database using a standardized form developed by the county Department of Health Services. Those patients not transported to a trauma center by emergency medical services, transfers, and those with isolated fractures are not included in the database. All 13 trauma centers use the Los Angeles County standard criteria in defining a trauma patient. The patient information was entered by each hospital's trauma registrar. The trauma registrars at each hospital are required to have initial training by Los Angeles County using a standardized schedule. All personnel are also required to attend recurrent training sessions. Chart abstraction for ICD-9 coding of trauma scores and variables pertaining to outcomes were the responsibility of each institution's registrar. A regular review of the participating centers is conducted by the emergency medical service authority to promote uniformity in reporting.

Data for this study were obtained between January 1, 1994, and December 31, 1996. Pedestrians who were injured by a motor vehicle were included in the study. The variables examined included: age, gender, ethnicity, Revised Trauma Score (RTS), Injury Severity Score (ISS), Glasgow Coma Scale (GCS), blood alcohol level, length of ICU stay, length of hospital stay, type of operation performed, mortality, postinjury functional capacity, and payer source. The ISS was calculated by each hospital trauma registrar. The type of operation was based on the ICD-9 surgery code entries in the database. For the purpose of data analysis, the ICD-9 surgery codes were grouped into categories based on the anatomic distribution. The categories included intracranial, face, spine, chest, abdomen, musculoskeletal, and others. Blood alcohol level was obtained in patients in whom there was a suspicion of alcohol intoxication during the initial patient evaluation. For the purpose of comparing the postinjury functional capacity status of the patients in this study, patient disability was based on Los Angeles County criteria. Patients who were seen in the emergency room and discharged without being admitted were defined as having preadmission capacity. Those who were admitted to the hospital and then discharged were defined as having temporary disability. Those who sustained injuries with permanent sequelae or those requiring ongoing treatment for a year after discharge were defined as having a permanent handicap.

The first four ICD-9 diagnoses reported were abstracted from the database. These were grouped by standard anatomic categories: head and neck, spinal cord and spinal canal structures, chest, abdomen and pelvis, musculoskeletal, external, and other. Head and neck was subdivided into intracranial and facial (including eye, ear, nose, mouth, and pharynx) and neck. Cervical spine injuries were grouped under spinal cord and spinal canal structures. Pelvic organ injuries such as bladder rupture or urethral tear were grouped into the abdomen and pelvis category. Pelvic fractures were grouped under musculoskeletal. The musculoskeletal category was subdivided into upper extremity, lower extremity, and pelvis. Each musculoskeletal subgroup consisted of fractures, dislocation, amputation, or crush injury. For purposes of comparison, patients were grouped by age: pediatric (age less than 15 years), adult (age 15 to 65 years), and elderly (age greater than 65 years).

Statistical analysis was performed using the SPSS software package (SPSS Inc, Chicago, IL). Pearson's chi-square test was used to analyze discrete data variables and to compare proportions. The independent samples t-test was used to compare means between groups. One-way ANOVA was used for more than two groups, and Tukey's Honestly Significant Difference test was used for pairwise multiple comparisons. Data are expressed as mean±SEM. A p value <0.05 was considered statistically significant.

JACS

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