Updated Dec. 28, 2017
Assessing trauma patients, particularly pediatric patients, involves understanding the mechanism of the trauma, what body systems may be affected by that mechanism and how the traumatic mechanism causes damage to specific organs.
Additionally, since hemorrhage is a result of trauma, understanding how the body responds to major bleeding is an important step in managing these patients. Transport of gases — oxygen and carbon dioxide — by the blood is a crucial link in the life support chain, which can be adversely affected by significant hemorrhage.
Pathophysiology of trauma
Mechanism of injury was once taught as a standalone reason for trauma activation of patients by EMS providers. More recently, however, mechanism has been seen as a tool or guide to assist providers in adequately assessing trauma victims.
The mechanism of a trauma is the collection of forces applied to the body during the incident. Knowledge of how those forces pass into and through the body and what body systems they influence during that process can give the EMS provider clues to what injuries to expect.
In Becky’s case, she was the unrestrained occupant of a vehicle which rolled over. As the vehicle rolled, it is reasonable to assume that she collided with the interior of the vehicle multiple times and could have also been struck by loose objects that were moving around as well. This would lead the provider to assume that multiple body systems may have been injured.
An important aspect of blunt trauma is the potential for injuries to internal organs without apparent outward signs of trauma. When a patient’s body collides with a vehicle, their internal organs still have forward momentum and may continue to move internally causing shearing. Additionally, seat belts and airbags — if improperly used — can cause compression of organs. When air-filled organs are compressed the air can be displaced. When solid organs like the liver, spleen and kidneys are compressed they may fracture and bleed [1].
Assessing pediatric patients for trauma
The actual assessment of a pediatric trauma patient is similar to an adult patient. What differs is the ability of the pediatric patient to participate and in some cases understand the assessment when compared to an adult.
Pediatric patients may be uncomfortable with strangers asking them questions and may be concerned about the safety and health of their parents. Extra attention should be paid to calming the patient and building a good rapport — in the presence of parents or caregivers whenever possible — before performing the assessment. Engaging with the patient’s caregivers may help convince the patient that you are there to help.
Additionally, assessing a patient visually before performing a hands-on assessment may help to guide your efforts. In Becky’s scenario, the presence of abdominal bruising should be concerning and should make that anatomical region one of highest priority.
Dynamics of shock in pediatric patients
EMS providers may be familiar with the idea that pediatric patients are able to maintain a state of compensated shock for longer than adults. When these mechanisms fail, however, a pediatric patient may have sustained a greater percentage of blood loss and can decompensate rapidly.
The reason for this lies in the way in which the body compensates for shock. By constricting peripheral vasculature — like in the extremities — the body increases vascular resistance and maintains blood pressure. Doing so ensures that blood is able to reach the brain and vital organs.
In pediatric patients, there is generally no existing disease process which inhibits the body’s ability to compensate. As a result, blood pressure alone may not be sufficient to predict shock severity in pediatric patients like it is in adults [2].
In Becky’s case, her heart rate is elevated for her age and her pulse pressure — the difference between the systolic and diastolic readings — is narrow. These may be early signs of decompensation and along with the findings of abdominal bruising in the setting of blunt trauma should be concerning.
Risk factors in motor vehicle collisions
Hypothermia is a risk factor in all trauma patients. With trauma often occurring outdoors, patients can quickly become hypothermic in any weather but are at a much greater risk in colder climates. Hypothermia can causes significant clotting issues for patients and when coupled with multi-system blunt trauma can create a situation where a patient may suffer from hypovolemic shock more quickly than anticipated. Pediatric patients, with a high ratio of body surface area to body mass, are at an even greater risk of becoming hypothermic due to rapid loss of body heat [2].
Properly used child safety seats reduce the risk of death by 71 percent for infants and 54 percent for toddlers between the ages of one and four. A properly installed booster seat reduces the risk of serious traumatic injury in children four to eight years of age by 45 percent [3].
Unfortunately, however, a U.S. Department of Transportation field study found that 59 percent of car seats and 20 percent of booster seats are installed in such a way that their ability to protect a child may be reduced [4]. As a result, EMS providers at a motor vehicle collision scene should not assume that a patient in a car or booster seat is free from trauma.
Transport of gases by blood
One of the most important links in the chain of life support is the ability of blood to transport gases. Assuming that ventilation is occurring effectively, respiration involves moving gases into and out of the blood at a cellular level. If a patient is significantly hypovolemic due to hemorrhage, a portion of the blood lost was red blood cells. This places the patient in a state of anemia, or low hemoglobin.
In this case, oxygen may be moving into the lungs but there are not enough hemoglobin molecules to take up that oxygen. At the same time, the cells of the body are producing carbon dioxide but there is insufficient hemoglobin to transport that gas to the lungs for exhalation. This is another example of a ventilation/perfusion mismatch.
Conclusion
Concerned about Becky’s exposure to a cold environment, you move her to the ambulance before completing your secondary assessment. You ask her mother, who was already assessed and found to be uninjured, to climb into the back as well. Your paramedic partner starts an IV and gives Becky a small fluid bolus. You transport Becky to the pediatric trauma center where she undergoes surgical repair of a spleen laceration. She is expected to fully recover.
This is a brief overview of trauma mechanism, assessment and treatment. To learn more, read these articles on trauma and pediatric care. Also contact your training officer or medical director to see what classes and continuing education may be available in your area.
References
1. McSwain, N. E. (Ed.). (2016). Kinematics of Trauma. In Prehospital Trauma Life Support - Eighth Edition (pp. 70–113). Burlington, MA: Jones & Bartlett Learning.
2. McSwain, N. E. (Ed.). (2016). Pediatric Trauma. In Prehospital Trauma Life Support - Eighth Edition (pp. 429–455). Burlington: Jones & Bartlett Learning.
3. American Academy of Pediatrics. (2015, December). Child Passenger Safety. Retrieved from https://www.aap.org/en-us/advocacy-and-policy/state-advocacy/Documents/CPS.pdf
4. US Department of Transportation - National Highway Traffic Safety Administration. (2015, June). National Child Restraint Use Special Study. Retrieved from http://www-nrd.nhtsa.dot.gov/Pubs/812157.pdf
