Out-of-hospital management in traumatic brain injury

Chapter 3
Out-of-hospital management in traumatic brain injury


Peter R.G. Brink


Trauma Center, Maastricht University Medical Center, Maastricht, the Netherlands


Introduction


In developed countries, the existence of organized trauma systems is the base for providing good care for trauma patients, from the scene of the accident through rehabilitation. Developing countries have adapted aspects of these systems, and further development of national or regional trauma management systems is likely to be a very cost-effective measure for reducing mortality and improving outcome for accident victims.


Trauma systems link organizations working in the field of acute care together, allowing uniformity of terminology and adapting the evidence-based guidelines. In most developed countries, well-trained paramedics are the backbone of the emergency medical system (EMS) and are responsible for the first part of the trauma chain, the prehospital phase. Under specific circumstances, paramedics are supported by physicians. In geographically dispersed regions, the use of helicopters helicopter emergency medical system (HEMS) as an adjunct for transportation is helpful.


The practice of medicine in the prehospital environment is quite different from what is encountered in the hospital. Potential risks from hazardous materials or environmental and climatic conditions must be considered, which could present risks for both patient and rescuer. In cases of entrapped patients, a multidisciplinary coordination between rescue and medical teams is mandatory. Paramedics or EMS personnel have a complex job, requiring intensive training in invasive procedures and decision making.


Focusing on the trauma patient with a traumatic brain injury (TBI), guidelines for the optimal protection of the damaged brain in the prehospital phase are evolving and are sometimes conflicting. In this chapter, generally accepted guidelines for the assessment and treatment of brain-injured patients as well as controversies will be discussed.


A high index of suspicion for the existence of a brain injury is required when paramedics start treating a trauma victim. In situations where paramedics encounter patients with a possible or obvious injury of the brain, guidelines are used to guide assessment of the patient on the spot. These guidelines are based on the probability of having a brain injury due to the mechanism of the injury. Penetrating injury of the skull and/or face is a simple clue indicating that injury of the brain is likely. High-energy impact, as is common in motor vehicle accidents, is an important factor for the existence of brain injury. In such cases (Box 3.1), brain injury should always be suspected, and measurements should be directed to create an optimal situation for the patient and the brain.


Other informations found during the initial physiological assessment of the patient gives further clues that the brain is injured in the accident. In all potentially traumatized patients, a simple algorithm is used assess the victim rapidly. The paramedic always starts his or her assessment by asking a simple question of the patient. If the answer is coherent and in a normal voice, it can be assumed that the airway is patent. If the patient does not answer, or his answer is inappropriate, further investigation into the level of consciousness is required. Increasing the intensity of the stimulus by talking louder and/or by administering a noxious stimulus is usually the next step in order to evaluate the level of consciousness.


The paramedic should categorize the patient as having a level of consciousness above or below a Glasgow Coma Scale (GCS) of 8. In patients with a GCS ≤ 8, the algorithm of the ABC starts with maintaining an open and secured airway according to the Manual of Prehospital Trauma Life Support [1]. This algorithm was developed during the early 1980s in the USA, was adopted by the American College of Surgeons in 1982, and has since become the international standard. The algorithm is revised every 4 years by an international group of experts, based on newly available evidence. In general, in patients with a GCS > 8, without other reasons for a compromised airway (facial or neck injury, inhalation injury), the focus on the airway is less prominent than in the group with a GCS ≤ 8.


The basic rules are always the same. The type and severity of the brain damage does not play a role in the initial assessment. The principle is “the best way to protect the injured brain is to optimize perfusion.” Maintaining or restoring cardiopulmonary stability is the next critical step in order to improve perfusion and oxygenation of all organs, including the brain.


The ABCs are designed to assess and treat disorders in oxygen intake, ventilation (either hypo- or hypercapnia), and circulation. At the scene, only physiological parameters can be assessed (Box 3.2), whereas full evaluation of the level of consciousness takes time and pathoanatomic information is lacking until CT scanning is performed. This focused information allows the implementation of measures to optimize the condition of the patient and to prevent secondary brain damage, such as preventing hypoventilation and hypovolemia, which have clear detrimental effects on survival and quality of life [2–5].


Because in the ATLS doctrine the sequence of assessment is mandatory (first airway, followed by ventilation and then circulation), the focus on brain injury seems to be placed on the back row, usually for good reasons (Figure 3.1). In the primary survey, every significant disorder discovered needs direct action. That means when the airway is compromised, it needs corrective action before ventilation is assessed. The goal is to stabilize the patient by ensuring an open airway, sufficient ventilation, and adequate circulation within the shortest time possible. Part of this optimizing process is the delivery of high-flow oxygen (100%O2, 10 l/min flow rate) using a non-rebreathing mask, since all trauma patients experience a higher level of metabolism due to stress.

c3-fig-0001

Figure 3.1 Algorithm for the prehospital management of traumatic brain injury



(Source: Salomone and Frame [30]. Adapted with permission from McGraw-Hill).


These steps to restore oxygen delivery to tissues support the brain. Only after the phase of resuscitation, when the airway is safe, oxygen is supplied (a systemic saturation between 95 and 100%), and the circulation is under control (bleeding is controlled and volume is prudently replaced), is it time to assess the damage to the brain. Roughly three levels of severity of brain damage are assessed, as they have consequences for transportation: mild, moderate, and severe. Each is discussed as follows.


Prehospital management of mild TBI (GCS 13–15)


Mild TBI characterizes approximately 80% of patients seen with a head injury [1]. Disorientation, amnesia, and/or temporary loss of consciousness are signals to the paramedics that the brain could be injured. Confounders like alcohol or drug intoxication could sometimes be a problem. Hypoxemia and/or hypovolemia may also mimic minor brain injury, but these should have been ruled out or treated within the first part of resuscitation. When signs of mild brain injury are present, unexpected deteriorations occur in about 3% of cases [1]. The mechanism of injury and patient-related factors plays a role. High-energy impact, direct blow on the head (fall or heavy object), or perforating injuries should be a clue demanding in-depth investigation by a specialist in a hospital. For the patient-related factors (Box 3.3), the use of anticoagulants is the most risky.

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Aug 6, 2016 | Posted by in NEUROSURGERY | Comments Off on Out-of-hospital management in traumatic brain injury

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