Scene Size-up (HB)

This topic will discuss the components that make up the Scene Size-up triangle. You will be able to make a decision to enter a scene, identify mechanisms of injury, and have an idea of the resources needed to manage the scene.

The scene is simply the place where the emergency took place. It encompasses the people, place, and events that led up to the reason you are managing a patient.

You must always maintain awareness of the scene and always seek to improve the scene’s components. Our goal in the scene size-up is to “stabilize the scene.”

Safety

The above video is not real–it is a training video (though you’ll see it get passed around as real). Regardless, the concepts are valid and essential. Unless you can safely navigate a scene, you should strongly consider avoiding it. In the above, had it been real, you would have needed an SCBA (Self Contained Breathing Apparatus) or gas mask capable of handling that material.

A common phrase thrown about is “safety first.” While this is an excellent idea, we ascribe to a version coined by Mike Rowe (of Dirty Jobs fame)–“safety third.” By the very nature of the responsibility we are undertaking, we put ourselves into less ideal situations. We would never be outside, in austere environments, or with limited resources if we wanted a completely safe environment.

However, we do need to be smart. Being smart about safety means not rushing into an environment and ignoring risk. We must pay attention to dangerous things and, if we choose to engage, to mitigate those risks. Your primary goal is NOT to become a patient yourself. While the desire to rush in and treat a patient is high, you must think before acting. Look around. Identify the hazards. Assess the risk and mitigate the hazards by evaluating active threats versus potential threats. If we encounter an unsafe scene, we move the patient away from the problem or move the patient’s problem away.

Assessing a scene’s safety is where situational awareness is critical and can be lost very easily. As an emergency rapidly unfolds in front of us (and we know the patient), we can easily focus on the screaming, bleeding friend we just saw get injured and simultaneously lose sight of the big picture.

Also, note that safety threats can be immediate or may progress over time. The patient is trapped under a snag with injuries, and bad weather is developing. We can certainly stay in place and treat while waiting for transport, but we might be putting the patient (and ourselves) at risk for environmental exposure.

The concept of LCES (lookouts, communications, escape routes, and safety zones) fits neatly into the concept of safety.

Think of the “your’s” when you are thinking about the safety of the scene:

• YOUR self,
• YOUR team,
• YOUR patient.

Ask the following questions:

• Is the patient safe right now? If not, can you make them safe? Can you keep them safe?
• Is the scene safe right now? If not, can you make it safe? Will it stay safe?
• Consider a scene with a downed powerline bouncing around between you and the patient. What would you need to get to the patient safely?

How about if your patient was at the base of a rock wall, and small pebbles and rocks were still raining down?

What if you witnessed lightning strike in the middle of a group of people in an open field, a couple of the people are not moving, and the storm is still going on with lightning and thunder still active and close?

Mechanism of Injury

Mechanism of Injury (MOI) just refers to the forces that created the injuries on the patient. A patient can have multiple mechanisms.

Consider a patient hiking along an exposed ridge. This patient has a history of diabetes and has been exerting more heavily than usual and not paying attention to food intake. They get dizzy and stumble and fall over the edge of a fifteen-foot drop. You find them at the bottom 20 minutes after the accident, lying on their side, unconscious but breathing, with obvious deformities to their lower leg (they appear to have a second knee just above the ankle), and multiple scrapes with slow bleeding. The obvious critical problem is that they are unresponsive. Your first impression might be that they impacted their head and have a traumatic brain injury. But on further examination, you don’t find any signs of injury to the head. While multiple of the injuries have a traumatic mechanism, the critical problem is medical. The low blood sugar situation that caused the stumble in the first place has progressed, and they are slipping further toward unresponsiveness. What if it had been an hour (or more) before you found them in the rain?

What happened? What is causing the problems?  We look for mechanisms in the following order:

• Trauma
• Medical
• Environmental

Traumatic mechanisms are generally easy to find. Some external force has interacted with the body beyond the body’s ability to compensate. This force causes damage to the structure and functions as the energy disburses. A couple of properties from physics explain a lot of this:
Objects at rest remain at rest till acted upon by an outside force.
Objects in motion remain in motion until acted upon by an outside force.

When we determine a mechanism of trauma, we need to find answers to questions about the forces involved. For example, let’s assume we have a patient that fell. We want to know:

• How did they fall?
• How did they land from the fall?
• What did they land on? Was it soft? Was it hard?
• Did they hit anything else as they fell?
• If a moving object struck the patient, how big was the object? How hard did the object hit them? How far was the patient thrown from the point of initial impact?

Medical mechanisms are caused by the failure of the structure or function of one the body’s systems. These mechanisms can be from either a previously existing problem (chronic) or sudden onset (acute).

Patients with a previous history can be easier to figure out than the patient who is experiencing something for the first time–the patient likely knows what is going on and can help you with the assessment. That is why you need to get a good history. Specifically, you need to focus on the past medical history and the events leading up to the present problem.

Environmental mechanisms are caused by something in the environment that negatively affects the body’s functions. These factors could be anything from temperature extremes to toxins to altitude.

Resources

Logistics will make or break an emergency. Ideally, we would like a fully stocked ambulance with an adjoining surgical suite; the reality is that we have to make do with less in these situations. Because your access to equipment will be limited and you may have limited ability to request supplies, it is crucial to quickly identify what you need.

When you initially approach a scene, you should decide what you need based on mechanism, and if you can, request resources that may take a long time to receive. Suppose you have multiple patients, and it is clear there is a mechanism of significant trauma. In that case, it does not hurt to order up a helicopter–you can always cancel it once you get hands-on with the patient (or patients) and can better assess the injuries.

The three categories of resources you will need are:

• Equipment,
• Personnel,
• and Transportation

Questions you should ask about those three categories:

• What do you need right now to stabilize your patient, and where do you need it?
• What do you need later to support your patient (or transport that patient to a better location), and where do you need it?
• Do you need help from the outside, or can it be taken care of with what you have?

Every incident will require its unique list of resources based on the injuries, location, and terrain. Think about what resources you would need for the following two patients:

• A patient with a dirty wound to the hand that can be walked to a utility vehicle and driven a short distance down a Dozer line to meet an ambulance at a drop point.
• A patient with an unstable lower leg injury with poor circulation, sensation, and motor function is one-mile downhill from a landing zone in steep, rough terrain with only four other personnel on the scene.

As your incident progresses over time, your needs may change, and you need to readjust as necessary. You may need more (or fewer) resources than the original plan required.