BACKGROUND: Emergency room thoracotomy (ERT) can be life saving in patients with penetrating chest injury. A protocol was established at our institution stating that ERT be performed for cases of cardiac tamponade secondary to penetrating chest trauma on patients with vital signs/mentation in the field or on arrival to the emergency room. To validate our protocol, we reevaluated patients undergoing ERT at our institution. METHODS: In our retrospective review, there were 49 patients undergoing ERT over a 6-year period. RESULTS: Survival in patients with vital signs was approximately 50%. Survival in those without was 0%. Compared with the preprotocol data, the number of ERTs declined from 32.2 cases per year to 8.1 cases per year. Overall survival increased from 4% to 20%. Neurologic outcome remained unchanged. CONCLUSION: We believe that the data validate our protocol, and the establishment of a guideline has enabled us to maximize patient survival and minimize exposure risks to our staff.