Impact of speed limit. I. Chest injuries, review of 966 cases
Alyono, D.; Perry, J.F.
Journal of Thoracic and Cardiovascular Surgery 83(4): 519-522
1982
ISSN/ISBN: 0022-5223 PMID: 7062764 Document Number: 185015
Traffic fatalities have decreased since the reduction in the speed limit to 55 mph. However, there has been no report documenting a decrease in the severity of chest injury from automobile accidents. From Jan. 1968-Jan., 1980, 966 patients with chest injury from automobile accidents were admitted: 463 during the period Jan. 1968-Dec., 1973 (before speed limit change, 1st period), and 503 during the period Jan., 1974-Jan., 1980 (after reduction of speed limit, 2nd period). The mortality during the 1st period was 17.3% (80/463), which was 16.1% higher than 2nd period, 14.9% (75/503), P > 0.05. There were no significant differences in number of the following chest injuries: multiple rib fractures, 77.8% (360/463) vs. 73.0% (367/503); pneumothorax, 41.7% (193/463) vs. 39.4% (198/503); lung contusion, 25.9% (120/463) vs. 24.9% (125/503); diaphragm rupture, 3.9% (18/463) vs. 4.2% (21/503); tracheoesophageal fistula, 0.4% (2/463) vs. 0% (0/503); cardiac injury, 3.5% (16/463) vs. 5.6% (28/503), or aortic injury, 3.2% (15/463) vs. 4.0% (20/503). There were statistically significant differences in the following injuries: hemothorax, 42.1% (195/463) vs. 29.2% (147/503), P < 0.01; sternum fracture, 6.7% (32/463) vs. 3.8% (19/503), P < 0.01; tracheobronchial rupture, 1.5% (7/463), vs. 0% (0/503), P < 0.01; and flail (19/503), P < 0.01; tracheobronchial rupture, 1.5% (7/463), vs. 0% (0/503), P < 0.01; and flail chest, 14.7% (68/463) vs. 7.2% (36/503), P < 0.001. During the 1st period the following were significantly higher: first 24 h blood replacement, average 1.9 vs. 1.4 U P < 0.05; 48 h chest tube drainage, average 358 vs. 216 ml, P < 0.001; respirator use, average 1.75 vs. 0.42 days, P < 0.001; and hospitalization, average 15.0 vs. 13.1 days P < 0.05. Thus the mortality, morbidity, and severity of chest injury were lower after the reduction of the speed limit to 55 mph from 70 mph.