The stress response
A working knowledge of the stress response is important to help understand the physiologic impact of major trauma on the patient, especially as it applies to the initial phases of resuscitation. Hormones, the autonomic nervous system and locally released agents such as cytokines produce a cascade of interactions to produce a host of responses that follow a recognized pattern, the depth and duration of which is variable. The initial response is aimed at maintaining adequate substrate, especially oxygen, delivery to the organs. This can begin immediately after injury. The initial phase is characterized by the release of catecholamines and vasoactive hormones, with increases in heart rate, cardiac contractility and cardiac output. Peripheral and splanchnic vasoconstriction occurs and extravascular fluids are mobilized to maintain blood volume. Blood glucose levels rise, free fatty acids are mobilized, and a peripheral leucocytosis is noted. The initial phase, the ebb, gives way to the flow phase as metabolic emphasis shifts to providing substrate for healing. It can be difficult to separate the ebb phase of the stress response from the ongoing consequences of inadequate resuscitation.
Death from major trauma can occur immediately, or early (often due to exsanguination) or delayed for weeks and then be a consequence of multiple organ failure. This last peak of deaths represents a major consequence of an exaggerated altered body metabolism in response to trauma, the ongoing impact of inadequate resuscitation, or indeed both providing ongoing stimulus for a profound stress response. This hypermetabolic state, characterized as the systemic inflammatory response syndrome (SIRS) can lead to a syndrome of multiple organ dysfunction (MODS), which is responsible for late trauma deaths.
A The trauma response
B Organization of the trauma resuscitation area
C Organization prior to arrival.
An area dedicated to the resuscitation of the trauma patient should be established, usually as part of the Emergency Department. The area however should be removed from the more general areas of the Emergency Department, be in close geographic proximity to the Operating Suite, and be secure so that access by non-medical personnel (family, friends, media, other combatants) be limited. Easy access to the radiology suite with CT scanning and the Intensive Care unit are desirable.
The dedicated space must be large enough to allow the team to function while performing any of the procedures necessary during trauma resuscitation. A well-lit room with mobile light sources is ideal. Provision of overhead radiant heating sources and individual room ambient temperature control to prevent hypothermia should also be included.
Communication in the trauma resuscitation room is essential, and is enhanced by use of a white board marker to record prehospital details and the current on-call team, a podium for the nurse scribe to work, telephones with extensions separate from the other functions of the emergency department
Equipment and placement.
Careful consideration of the placement of equipment in the trauma resuscitation room should be made to maximize functionality and make the best use of he space available. Only a minimal amount of equipment should be stored in the work area
Universal barrier precautions
The body fluids of any trauma patient should be considered a potential infective agent. Eyewear and gloves are mandatory, and a mask, impervious gown and overshoes additional help. On a practical note the routine wearing of barrier precautions will reduce laundry costs. These items should be available in a designated area, ideally at the entrance to the resuscitation area.
Remember the golden rule: protect yourself before the patient. Those few moments to don protective garb rarely influence the ultimate patient outcome, and indeed produce the mindset for a controlled, practiced trauma response.
Another barrier should be thought of at this moment. Wearing lead gowns under the waterproof overgrown or slipping a lead gown on at the completion of the primary survey allows the resuscitation to proceed while the initial X-rays are being performed. The assessor can proceed to the secondary survey and the proceduralist continues with urethral catheterization while the CXR is being done, for example.
Key points
- Protect yourself before the patient!
Trauma team members (Fig. 2.3)
Ideally the trauma team should assemble, decide on roles and be positioned prior to the patient’s arrival. Those few moments of introductions, assignment of roles and establishment of the leadership role are vital. Composition of the trauma team will vary from institution. Establishing a rapport with the nursing staff, and acknowledging their sometimes vast experience, is very important at this point in time. Learn and use first names. Where a full response is possible the ideal team would be:
Nurse 1. Principal nurse who will have prepared the room prior to the patients arrival and will accompany the patient until definitive care. Should begin the resuscitation standing on the patients left side, ready to connect the patient to monitoring immediately on transfer to the resuscitation trolley.
Nurse 2. The proceduralist nurse, who in addition to drawing the initial bloods is ready to set up any trays required for interventions.
Nurse 3. The historian or scribe. Will also facilitate communication with other areas of the hospital such as the operating room and blood bank. Need not necessarily be a nurse.
Doctor 1. The team leader. Stands at the foot of the bed.
Doctor 2. The primary assessor. Stands at the patients right side, stethoscope at the ready.
Doctor 3. The airway. Stands at the patient’s head, controlling the airway. Must never leave that station until directed to do so by the team leader.
Doctor 4. The proceduralist.
The various medical roles need not be limited to particular specialties but each team member must have the skills to fulfil tasks directed to them.
Radiographer. Stands off to one side, with universal precautions on. May have already placed a X-ray plate on the resuscitation trolley to facilitate a rapid CXR.
Wardsman. Stands at the ready, especially to rapidly dispatch blood for cross matching. Useful too for the combative patient.
Blood bank technician. Responds to the call for the trauma team with an enquiry after ten minutes to determine the likelihood of the need for an operating room.
O.R. nurse in charge. Responds to the trauma team call with an inquiry after ten minutes to determine the likelihood of the need for an operating room.
Nursing supervisor. Assesses the resources the patient will require and if necessary call the extra staff required.
In smaller hospitals clearly the first medical responder will be required to fill all roles. Nursing support and experience is invaluable in these circumstances. The resuscitation should then proceed along ATLS /EMST lines. Should a second responder arrive then that person should be assigned to be the airway doctor until the primary survey is completed. Only with a full complement of nurses and doctors can a team leader have the luxury of stepping back to the patient’s feet and directing the team.
The trauma team and team leadership
The clinical priorities of trauma resuscitation, as taught in the ATLS course, consider the steps in a longitudinal manner. A begets B, which begets C. this is considered a vertical resuscitation and entirely appropriate when only one or two physicians can attend the patient. However in the modern trauma receiving hospital a team is activated to respond to the priorities of the acutely injured patient. In a well-drilled team multiple facets of the assessment and interventions required to continue the resuscitation may be carried out simultaneously. This is summarized in Figs 2.4 and 2.5.
The horizontal trauma resuscitation needs to have all team members having well defined roles, appropriate to the skills of that person. The team needs to be lead by the most senior clinician in the team. The leadership of the team is the single most important element of a successful trauma resuscitation. This usually works best with the team leader standing at the foot of the bed beside the nurse scribe, while another team member conducts the primary survey. Direction to team members should be given in a strong clear voice, addressing them by name so there can be no ambiguity about who has been assigned a particular task. Assessment findings should be communicated back to the team leader and scribe nurse in an equally clear voice. Control of noise levels during a resuscitation is a marker of a smooth running resuscitation. The hype and noise levels featured in TV trauma resuscitation represent poor examples of how a patient might be rapidly assessed and resuscitated. Shouting or addressing team members by anything other than their name should not be condoned. During a time critical trauma resuscitation there is often little room to debate. Clinical priorities are made by the most experienced clinician who is also leading the team, and dissent of decisions should be reserved for after the event. One trap for the team leader, as the most experienced clinician, is to be drawn in to the resuscitation, especially to perform procedural tasks. This may result in a loss of focus and lack of direction of the resuscitation. However on occasion the team leader must undertake procedural tasks. Another important skill for the team leader is to tactfully reassign procedural tasks when it becomes clear the person asked to do the task e.g.. inserting a large bore IV cannula, is not proceeding due to lack of expertise. An alternative to the most senior person being the team leader might be when an in-training clinician is given an opportunity to lead the team with the more senior clinician participating and offering advice.
An important task for the team leader is to ensure, along with the nursing staff, that all team members have adequate barrier precautions. No staff should be allowed inside the box that surrounds the patient without donning protective gear and identifying unprotected staff is an effective way of establishing oneself as the team leader.
No member of the team should leave the resuscitation area without clearing it with the team leader. At an appropriate point in time, when it is clear that a patient does not have pressing priorities and after the primary survey has been completed, the team leader may chose stand down the team. Non-essential team members should be invited to return to their other duties outside the trauma resuscitation. Barrier precautions may be relaxed.
Trauma resuscitation is not a spectator sport. The team leader must firmly control the hubbub from onlookers, and on occasion’s direct non-essential staff to leave the trauma resuscitation area. Senior staff often provides examples of this behind the scene noise, which only distracts from the job at hand.
The trauma team members should be drawn from suitably skilled physicians from the fields of Surgery, Emergency Medicine, Anaesthesia, and Critical Care. Other clinical disciplines, especially general practitioners in smaller hospitals, need to be involved. The trauma team must always include a surgeon or their designated representative, the surgical registrar. This permits timely response from the surgical teams in critical situations. If the surgeon is not present their representative should notify the surgeon that trauma resuscitation is about to take place, even before the patient arrives. In this way the maximal responsiveness will be had, as it is easier to stand a surgeon down than to scramble to locate and free from other responsibilities should that be required. That ingrained desire to “present” the patient with a complete clinical summary on initial registrar to surgeon contact should be resisted. There is value in having junior resident staff and medical students attached to surgical teams or the Emergency Department act as team members at trauma resuscitation. They can perform simple procedures but more importantly will, as they mature clinically, be more ready to assume their roles in the team trauma resuscitation situation.
Activation of the trauma team should be by predefined criteria appropriate to each hospitals staffing and trauma caseload. Many criteria for team activation have been advocated - the important issue is to develop criteria and then modify them according to the local experience. There is however no place for a wait and see approach. This risks losing valuable moments. The trauma team should be activated whenever a patient fits the predefined criteria. An overtriage rate of 50%, that is with no time critical injuries, is considered acceptable to capture those patients who truly do. Even if the patient does not have time critical injury most trauma team activations lead to admission to hospital. In addition the non-critical resuscitation is a golden opportunity for the team to practice, without life and death pressure, the rapid assessment and transfer to definitive care needed on other occasions. Overtriage has lead to enthusiasm for a two tiered response based on the patient’s prehospital physiology. Two tiered responses are well tried and have much to recommend them as a judicious use hospital personnel and resources, especially where there is a sophisticated trauma response. A two tiered system should always contain the flexibility to upgrade rapidly to a full team response when required.
Trauma team members should be aware of the experience and skill of their nursing colleagues and be sensitive to their “suggestions” during the resuscitation. Based on extensive experience these suggestions are nearly always appropriate.
For those hospitals with a sufficient volume of major trauma cases and a well-established quality assurance process then real time video taping of trauma resuscitations and subsequent review is an invaluable tool for improving team performance.
The more often the trauma team is activated the more seamless the team functioning will be. Therefore, paradoxically, for the smaller hospital where only a small complement of trauma responders might be drawn together, there is an even greater burden to prepare for the arrival of the major injured patient. For example, in a country hospital where a time critical injury may only arrive once every three months careful planning, dry or mock resuscitation’s, and a critical debrief of the response after the arrival of such a patient assume an even greater importance than in larger institutions. Call and back up arrangements to provide the largest support possible should be worked on. In such places the training afforded by ATLS / EMST courses will increase confidence by the trauma care provider that they gave the best possible care for the patient with the resources available. Hospitals in smaller communities work under the added pressure often of at least one team member knowing the injured patient.
Finally, even with the best trauma responses patients will die. It is inevitable. It can be emotional. Again the team leader must lead: reassure all the team members of the value of their contribution, leave a review of performance until the dust has settled, contact the coroner or medical examiner, and seek out family or next of kin.
Trauma systems
Trauma systems describe a coordinated response to major injury in a defined geographic region that permits prompt access to optimal care. The essence of trauma systems is delivering patients to facilities with the resources to deal with that particular patient. This inevitably requires bypass of some hospitals sometimes. Trauma systems have shown a capacity to reduce death and disability, and enhance equity of access for both the urban and rural patients to optimal care. Optimal care includes all phases of the management of injury - prehospital, resuscitation, definitive care, rehabilitation.
Development of a trauma system is a political process as much as it is medical, because it determines how resources are allocated and where. A trauma system has many components, including leadership and political will, continuous planning and development, adequate financing, public education and injury prevention and efficient communication networks. Above all a trauma system details where in a health care system the injured patient should be. Different levels of care within a trauma system have different facility and personnel requirements. These are detailed in “Resources for the optimal care of the injured patient. Once designation and accreditation of trauma centres is undertaken there is a requirement for periodic review to ensure compliance with the agreed standards.
Paediatric resuscitation
(see also Chapter 00 - Resuscitation and stabilization of the seriously injured child)
Key differences between adults and children in response to injury (Table 2.3)
Successful paediatric trauma management of the injured child depends on an understanding of the unique characteristics of children’s anatomy, physiology, development and psychology. It is important to anticipate and be prepared, with a full range of equipment and to the availability of expertise to assist with more difficult procedures or radiological interpretation, as necessary.
Children, especially small infants, are generally more vulnerable to hypoxia in the presence of the hypercatabolic state after trauma, because of a high basal metabolic rate, reduced functional residual capacity, increased work of breathing and a high oxygen consumption. They are also prone to hypoglycaemia because of limited glycogen stores and to hypothermia because of immature thermoregulation and relatively large surface area, with greater loss of water and heat. Children in a rather cold environment may therefore become hypothermic, which may exacerbate the shock. If these factors are not considered or prevented early on, the injured child may remain physiologically decompensated.
There is wider dissipation of impacting force over less body mass in small children making multiple injury more common, their reduced muscle bulk giving little protection to underlying organs and parenchyma. Children are therefore more likely to have underlying visceral injuries rather than overlying bony injuries. These injuries may take some time to become evident. Abdominal injuries are typical of this and may not present until 3 or 4 hours after a child’s arrival in the emergency department, the child eventually developing hypovolaemic shock.
Key points
After trauma children as compared to adults are more prone to:
- Hypoxia
- Hypoglcyaemia
- Visceral injuries
Important differences between children and adults are the normal ranges for vital signs (heart rate, respiratory rate and blood pressure). Vital signs are dependent on age, development and size and on the environment and situation and may not necessarily represent underlying pathology. The upper and lower limits, given in Table 2.4, are clearly defined and if breached should immediately raise concern. The rules of thumb in Table 2.5 can be a helpful guide.
Children and particularly small infants have small airways with poorly developed cartilage which tend to collapse, a large occiput, with an infantile anteriorly place high lying larynx all predisposing to upper airway obstruction. The small airways and large occiput in children can also predispose to upper airway obstruction. They also have a small mouth with a large tongue, which can cause relative airway obstruction. All of these factors can lead to imminent airway obstruction in a small infant even with minimal injury and render intubation more difficult. Minute ventilation, a function of both tidal volume and respiratory rate, is increased through an increase in respiratory rate. Therefore an unexplained increase in respiratory rate must be treated with greatest respect because it may reflect metabolic decompensation from uncontrolled shock. The infantile larynx is anteriorly placed and higher in the neck at around the C2-C3 level. Cuffed endotracheal tubes are recommended after 8 years of age. Children also tend to have a collapsible chest wall with poorly developed, easily fatigable muscle. Babies rely on diaphragmatic breathing and any compromise of diaphragmatic movement can precipitate respiratory failure. It is therefore important in a seriously injured child to consider venting the stomach and reducing the quantity of gastric contents to prevent diaphragmatic splinting. Infants less than 6 months of age also tend to be nose breathers and even simple nasal obstruction can cause apnoea; hence it is very important to have suction available.
Children have less contractile tissue per unit of myocardium (and a fixed stroke volume) and therefore cardiac output is limited by heart rate. Cardiac output is high in infants who have high energy (and oxygen) consumption and are operating high on the ventricular function curve. Although cardiac output falls in an almost linear fashion as blood volume is depleted, systolic blood pressure is sustained, even with 30% or more blood loss, because of increased vascular resistance secondary to peripheral vasoconstriction; diastolic blood pressure is elevated with a narrow pulse pressure. Cardiac output is rate dependent, so persistent tachycardia in a seriously injured child must be assumed to represent hypovolemia.
Children have a relatively short neck, making evaluation and immobilization of the cervical spine difficult.
Children are afraid of being hurt, they are also afraid of the unknown and often are very disturbed by the general air of panic and confusion that usually surrounds an emergency. Their behaviour in this situation may be inappropriate with emotional withdrawal or regression to an earlier developmental level. The approach needs to be developmentally appropriate and recognize the importance of the family unit in both accidental and non-accidental injury.
Key points
- Children are more prone to airway obstruction because of the anatomy of the skull
- Cardiac output in children is limited by heart rate
Injury patterns unique to children
Children have many patterns of injury that are unique and easily overlooked particularly in the case of multisystem injury. Although injury is often diffuse rather than localized leading to more serious system pathology and a greater morbidity and mortality rate it must be emphasized that the initial resuscitation period in the injured child is very much a respiratory rather than a circulatory phenomena. When managing the injured child the treating physician must be aware of the association between a child’s size, mechanism of injury and potential injuries likely to result. When a child is hit by a car the femur is at the level of the bumper-bar, the child’s trunk is often at the level of the hood of the car and as a result of the impact with the car the child is thrown always with the head landing on the road. This association of femur, chest and head injury is known as Waddell’s triad (Fig. 2.6). In this way timely intervention for the multiply injured child can be anticipated and planned. Non-accidental injury is an all too common problem that must be considered in multisystem injured child.
Head injury
This is the leading cause of death amongst all childhood victims of injury. Although having a better survival rate from head injury, children sustain a disproportionately large number of head injuries. They tend in the case of multiple trauma to have severe diffuse brain injury with variable outcome. Up to 80% of children dying of multiple trauma have a head injury.
This is due to the following reasons:
- Head to body ratio larger
- Less myelination
- Thinner, more compliant cranial bones
- Raised intracranial pressure more commonly seen than space occupying lesions. In the case of young babies and infants these can occur together and non-accidental injury needs to be considered
- An open fontanelle does not protect against increased intracranial pressure.
Spinal cord injury
This is being reported with increasing frequency in childhood multiple trauma. There are characteristics of the child’s spinal cord and differences in the types of injuries sustained that lead to important differences in the pattern of injuries seen. Many spinal injuries involve the upper cervical spine although lower injuries are now being increasingly reported. To the following characteristics contribute:
- Large, heavy head
- Weak neck musculature
- Hypermobility and laxity of ligaments and joint capsules
- Natural fulcrum for flexion at the C2/3 and C3/4 levels
- Horizontal orientation of articular surfaces.
Spinal cord injury without radiological abnormality (SCIWORA) occurs almost exclusively in children. Further a strong association exists between childhood lumbar spine injury and lap seat belts found in many motor vehicles. These lumbar injuries may be intraspinous (Chance) fractures but are frequently associated with other intra-abdominal injuries (including left acute traumatic diaphragmatic hernia).
Extremity injuries
The bones of the extremities tend to deform rather than fracture, although fractures are common and are associated with multiple trauma. Fractures are the most frequent injury missed in the child with multisystem injuries due to the higher incidence of incomplete or complete but non-displaced fractures. The pattern of extremities injuries in children can be attributed to a number of factors:
- Cortical bone is highly porous and easily disrupted
- Periosteum is resilient, elastic and vascular
- Radiological diagnosis is difficult
- Healing is rapid and non-union rare
- Ligamentous injury is rare
- Remodelling is in the plane of the fracture
- Ischaemic injury can occur
Thoracic injury
The presence of thoracic injury in children is a strong marker of severe and multisystem trauma. When thoracic trauma has occurred there is an 80% chance that other systems have been severely injured. The risk of physiologic derangement from thoracic injuries is high in children because underlying organs are often affected. Injury to the heart and great vessels is rare in children. This pattern of injuries is due to a number of factors:
Greater elasticity of bony and cartilaginous chest wall (lower incidence of fractured ribs and sternum, and flail chest) Kinetic energy is more readily transmitted to underlying parenchyma (high incidence of pulmonary contusion, pneumothorax, haemothorax or any combination.) Compensatory ability in the presence of pericardial or pleural collections is limited
Pneumothorax in children is often silent but lethal abnormality that requires a high index of suspicion on the part of the managing clinician. If a tension pneumothorax (see Fig. 26.8) is suspected and vital signs rapidly deteriorate, management (Fig. 2.7) must be prompt.
Abdomen
Abdominal injury is common in paediatric trauma, with the lap seat belt as a major cause. It is especially common in children with multiple trauma and a well recognized association in children with non-accidental injury. Abdominal tenderness, distension and symptomatic haematuria are clinical clues. The most common injuries are to solid organs such as liver and spleen, followed by bowel and pancreas. This pattern of injuries is due to a number of reasons:
- Solid organs have little protection
- Kinetic energy readily transmitted to parenchyma
- Small size predisposes to multiple injury
One important consideration when assessing the abdomen is to remember the well-known axiom “the stomach is always full” (Fig. 2.8). This is never so true as in the injured child. Unexpected emesis can be life threatening. Most commonly however gastric stasis which impedes venous return and splints the diaphragm can lead to cardiopulmonary compromise. Venting the stomach with an orogastric tube easily prevents this.
Pelvic injuries are mostly fractures and occur in pedestrian accidents. They behave differently from adult pelvic fractures with less haemodynamic compromise. However they are an important marker of multisystem injury and should trigger a search for other injuries.
Conclusion
Resuscitation is an ongoing process, on through to the definitive management phase. Just like the transition from prehospital to resuscitation phase the transition to definitive care should be accompanied by the formal handover of the care of the patient with a succinct, ideally written, summary of events thus far. Dedicated medical record sheets encourage the recording of the trauma resuscitation in the manner in which it occurred - prehospital, primary survey, secondary survey, imaging results, investigation results and injury summary.
Throughout the resuscitation and assessment phase the care providers need to keep an eye on the big picture - what are the patient’s injuries and what is the highest priority? Investigation should never impede resuscitation. Transfer to definitive care, especially the operating room, should not be delayed by lower priority concerns. The lack of a precise diagnosis should not stop you treating the patient (Table 2.6).
Key points
- Treat the patient. Do not a diagnosis make.
The joy of trauma cares remains. At the end of a trauma resuscitation you will have had the satisfaction of working as team. Many patients will survive their injury in spite of what you did. But occasionally you will be rewarded with the tangible satisfaction that the coordinated, timely assessment and intervention assembled for that patient has limited the morbidity of injury, and spared life or limb. That makes it all worthwhile.
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