Worldwide, traumatic brain injury (TBI) is a leading cause of death and permanent disability. In the United States, there are approximately 1.4 million reported cases of TBI each year. The real incidence is difficult to determine, however, since many patients never seek medical care or go to an emergency department.7 Of the reported cases, roughly 50,000 patients die and 235,000 are hospitalized. Age categories most affected are patients less than 5 years of age, those between 15-24 years, and those over 70 years of age. TBI results in lifelong disabilities for more than 30,000 children each year. The mortality rate fromblunt trauma without TBI is 1%; when TBI is involved, the mortality rate from severe blunt trauma is 30%.

Half of those who die from TBI do so within the first 2 hours of injury. It is now known, however, that all neurological damage does not occur at the moment of impact (primary injury), but rather evolves over the ensuing minutes, hours, and days. This secondary brain injury can result in increased mortality and disability. Consequently, the early and appropriate management of TBI is critical to the survival of these patients.

Emergency Medical Services (EMS) personnel are often the first healthcare providers for patients with TBI. Thus, prehospital assessment and treatment is a critical link in providing appropriate care. Treatment begins in the field and continues during transport by EMS providers who have varied skills, backgrounds, and qualifications. Over the past 30 years EMS has become progressively sophisticated, resulting in improved outcomes, particularly in cardiovascular10 and traumatic resuscitations. However, many challenges remain, especially in recognition and management of TBI in the prehospital setting.

Emergency medical care in the field is provided by a wide variety of personnel in the United States. The First Responder and EMT-Basic provide patient assessment and noninvasive intervention. However, a growing trend to offer additional training to the EMT-Basic now permits some of them to perform some invasive procedures, such as intravenous (I.V.) line placement and advanced airway interventions.EMT-Intermediate training includes invasive interventions, such as I.V. line placement, endotracheal intubation, and the administration of a limited list of resuscitation drugs. The EMT-Paramedic, who has the highest level of EMT training, is allowed to perform advanced patient assessment as well as endotracheal intubation, ECG recognition, I.V. line placement, needle thoracostomy, and the administration of a comprehensive list of medications. In many countries, physicians in ambulances or helicopters respond to the call and care for the patient in the prehospital setting.

This is the second edition of the evidence-based Guidelines for the Prehospital Management of Severe Traumatic Brain Injury, following the first edition in 2000. These Guidelines address key topics useful in the prehospital management of severe TBI. The following are notable changes from the first edition:

• In previous guidelines documents, Recommendations were assigned Levels (Standards, Guidelines, Options) based upon the degree of scientific confidence derived from the literature base (Strong, Moderate, and Weak, respectively). In this edition of the Prehospital Guidelines, recommendations are made without assigning Levels. However, at the end of each recommendation, the Strength of the Recommendation and the Quality of Evidence upon which the recommendation is made are clearly stated (refer to the Methods Section for a detailed description).
• The classifications of the quality of certain publications included in the previous edition have been changed. Publications are classified both by design and quality (see Methods section and Appendix A).
• All chapters are now presented in a new, uniform format. Each chapter was organized into the following chronological sections: Recommendations, Evidence Tables, Overview, Process, Scientific Foundations, Key Issues for Future Investigation, and References.
• A new "Treatment: Cerebral Herniation" chapter was added in order to emphasize the unique considerations in the treatment of these patients.
• Discussion regarding the utilization of sedation, rapid sequence intubation, and lidocaine was moved to the "Treatment: Airway, Ventilation, and Oxygenation" chapter.
• The topic of Brain Targeted Therapy was eliminated. The content was distributed across topics on Cerebral Herniation, Fluid Resuscitation, and Airway/Ventilation/Oxygenation.
• A new chapter, Decision Making Within the EMS System, is included and expands upon the "Hospital Transport Decisions" chapter from the previous edition. It addresses dispatch, level of care, transportation mode, and destination.
• Pediatric literature was added as a separate section for each topic.
• Publications cited in the text, but do not provide evidence for a recommendation, do not appear in the Evidence Tables.

Prevention: Although the treatment of TBI has improved considerably, it is clear that prevention must be a priority. EMS systems and providers are increasingly viewed as essential participants in injury prevention activities. EMS providers operate at the interface of public health, public safety, and individual patient care and interact daily with the public in a unique manner, as they are given entr´ee into homes, schools, and offices, affording opportunities to assess risk, capitalize on "teachable moments," collect data, provide community education, and function as advocates.

The National Highway Traffic Safety Administration (NHTSA) has identified injury prevention as an essential component for EMS education in its "EMS Education Agenda for the Future," and education in injury prevention is a part of the National Standard Curriculum (NSC) for paramedics. Combined with known successful prevention programs, such as helmet use, the nation's 800,000 prehospital providers have the possibility for profound impact in the realm of injury prevention.

To this end, many EMS systems have developed programs focused on injury prevention within their communities. These programs have targeted a variety of issues, including the proper use of child safety seats, fall prevention, and home safety inspections. However, to date there is limited evidence that specific injury prevention efforts undertaken by prehospital providers, including primary prevention programs, reduce the morbidity and mortality of specific injuries, including TBI. Therefore, the impact of the role of EMS provider and system injury prevention programs with respect to TBI cannot be determined by the available evidence. Thus, evidence-based guidelines for EMS injury prevention initiatives cannot be offered in this manuscript.

As it continues to expand, the field of EMS must continue to pursue the rigorous validation of specific interventions provided in the prehospital environment, including those that focus on injury prevention initiatives provided by EMS personnel. In the interim, EMS providers must continue to support the implementation of successful and validated individual and community based prevention efforts in the prehospital environment.

Though scientific evidence is insufficient to support a standard of care for many clinical practice parameters, this text has assembled the current scientific literature into a cohesive and comprehensive format in a manner that reflects the best evidence available to us. It is hoped that EMS personnel will find this information useful, and in turn, will use it for the benefit of patients with TBI.