Scene Size-up

• Scene size-up is the initial evaluation of an emergency scene to ensure safety and determine the necessary resources and approach.

• Key considerations during scene size-up include personal safety, safety of the crew, patient safety, and bystander safety.

• Scene size-up involves identifying potential hazards, determining the mechanism of injury or nature of illness, and assessing the need for additional resources.

• Effective scene size-up is closely related to other EMS topics such as patient assessment, communication, documentation, and operations in hazardous or complex environments.

• Understanding anatomy, physiology, and trauma management is essential for making informed decisions during scene size-up.

Standard

• Scene size-up involves gathering information about the environment and situation to ensure safety and guide emergency care decisions.

• You use findings from scene size-up, primary and secondary assessments, patient history, and ongoing reassessment to inform and adapt your emergency management approach.

• Integrating all assessment data helps you make informed decisions and provide appropriate care throughout the emergency response.

Core Concepts

• Identifying hazards at a scene is crucial for ensuring your safety and the safety of others; hazards can include environmental dangers, unstable structures, or violent individuals.

• Determining if a scene is safe to enter involves assessing for immediate threats and deciding whether it is appropriate to approach or if you should wait for specialized help.

• Mechanisms of injury refer to the way in which a patient was hurt (such as falls, collisions, or penetrating trauma), and understanding these mechanisms helps you anticipate the types and severity of injuries a patient may have.

• Determining what additional assistance may be needed requires evaluating the situation to decide if you need more personnel, specialized equipment, or law enforcement to manage the scene effectively.

Learning Objectives

• Scene size-up involves assessing the environment for safety, identifying hazards, and determining the need for additional resources before providing care.

• Recognizing potential hazards at a scene is crucial to protect yourself, your team, and bystanders from harm.

• Determining scene safety is the top priority because entering an unsafe scene can result in additional injuries or casualties.

• Personal protective equipment (PPE) may need to be modified based on specific scene characteristics, such as chemical spills, fire, or violent situations.

• Observing the mechanism of injury helps you predict possible patterns of patient injuries, guiding your assessment and care.

• Information about a medical patient’s illness can come from bystanders, family, the patient, medical alert tags, and the environment.

• You must assess each situation to determine if more resources, such as fire, police, or specialized rescue teams, are needed to manage the scene effectively.

Key Terms

• Blunt-force trauma refers to injuries caused by impact with a non-sharp object, often resulting in internal damage without external wounds.

• Penetrating trauma involves injuries where an object pierces the skin and enters the body, potentially causing direct damage to internal organs.

• Mechanism of injury is the process or event that caused the injury, which helps you predict possible injuries based on how the trauma occurred.

• Nature of the illness describes the underlying medical condition or reason for the patient's symptoms, important for identifying non-traumatic emergencies.

• Scene size-up is the initial assessment of the emergency scene to identify hazards, determine the number of patients, and decide on necessary resources.

• Danger zone is the area around the incident that may pose risks to responders due to hazards like fire, unstable structures, or violence.

• Index of suspicion is your level of concern for potential injuries or illness based on the scene, patient presentation, and mechanism of injury.

Scene Size-Up

• Scene size-up is the initial step in patient assessment, starting as you approach the scene.

• You must survey the area for threats to your safety, the patient's safety, and bystander safety before proceeding.

• Determine the nature of the call and assess if additional help is needed during this process.

Chapter 11 Visual Guide

• Scene size-up involves making ongoing, thoughtful decisions to identify and minimize hazards throughout an emergency call, not just at the beginning.

• Emergencies are dynamic, so you must continuously reassess the scene for new or changing dangers, such as hostile individuals or unstable vehicles and structures.

• A brief survey of the scene can reveal critical hazards (e.g., downed electrical wires) and provide clues about the mechanism of injury, such as vehicle damage indicating possible chest, head, or neck trauma.

• Specific observations, like a deployed airbag or a damaged windshield, should prompt you to assess for related injuries, especially in vulnerable passengers like children.

• Taking appropriate actions, such as requesting additional ambulances or notifying fire, power, and police departments, is essential to ensure safety and effective response.

• You must also take steps to protect bystanders by keeping them away from traffic, hazards, and patients.

Scene Safety

• Always assess scene safety yourself, regardless of who arrived first. Do not assume police, firefighters, or other EMS have already addressed all hazards; perform your own scene size-up for hazards, infection risks, mechanisms of injury, and number of patients.

• Begin scene assessment before arrival. Observe for other emergency vehicles, signs of power outages (like darkened areas), abnormal traffic flow, smoke, and other clues as you approach.

• Look for specific hazards upon arrival. Identify signs of hazardous materials (placards, damaged trucks, escaping liquids, fumes, vapor clouds), downed wires, broken utility poles, smoke, and collision victims near or away from vehicles.

• Follow the Incident Command System if present. Listen to the person in charge for instructions on ambulance positioning, protective equipment, patient locations, and specific hazards.

• Wear appropriate protective gear. This includes head protection, bunker coat, ANSI-approved reflective vest, and extrication gloves; adjust clothing for weather and temperature.

• Use your senses to detect hazards. Sniff for unusual odors like gasoline or chemicals that may indicate hazardous material releases.

• Establish and respect the danger zone around wreckage:

  • No apparent hazards: Danger zone extends at least 50 feet (15.2 meters) in all directions.

  • Fuel spill: Danger zone extends at least 100 feet (30.4 meters); park upwind and uphill if possible, avoid flares, use cones or reflective triangles.

  • Vehicle fire: Danger zone extends at least 100 feet (30.4 meters) in all directions, regardless of fire size.

  • Downed wires: Park at least one full span of wires away from the poles; wires may be energized and dangerous over a wide area.

  • Hazardous materials: Consult the Emergency Response Guidebook (ERG) or Incident Commander for safe parking distance, which may range from 50 feet (15.2 meters) to 2000 feet (609.6 meters) or more, depending on the material; always park upwind and, if liquid is present, uphill.

• Be alert for bystanders and follow signals from police or emergency personnel. They may provide critical information about hazards or injured persons.

• Never park the ambulance within the danger zone. Always position the vehicle to maximize safety for yourself and others.

SCAN 11-1

• Establishing a danger zone is critical in various emergency situations to ensure safety for responders and bystanders. For downed electrical wires, the danger zone should extend beyond each intact pole for a full span and to the sides for the distance severed wires can reach. Do not enter until the utility company deactivates the wires or trained rescuers secure them.

• For vehicle fires, park the ambulance at least 100 feet (30 meters) away and upwind from the burning vehicle if no other hazards are present.

• When hazardous materials are involved or threatened by fire, the size of the danger zone depends on the material. Use binoculars to read placards and refer to the Emergency Response Guidebook for safe distances. Always park upwind.

• In cases of spilled fuel, park the ambulance upwind and as far from the fuel flow as possible, avoiding areas where fuel could travel, such as gutters or ditches. The ambulance’s catalytic converter can ignite fuel, as it operates above 1000°F (538°C).

• For hazardous chemical spills, park upwind regardless of whether fumes are visible. Seek expert advice (e.g., CHEMTREC) through the Incident Commander if the material is known.

• Violence at crime scenes is a significant risk for EMTs. Never enter a violent situation to provide care; safety requires careful assessment as you approach.

• Key warning signs of violence include fighting or loud voices, visible or in-use weapons, signs of alcohol or drug use, unusual silence, and knowledge of prior violence at the location. These indicators should prompt heightened caution.

• If signs of danger are observed, take protective actions based on your training, the type of threat, and available help. Always prioritize personal and crew safety before providing care.

Point of View: EMT

• Scene safety is always the top priority—you must assess the environment before entering, as appearances can be deceiving and hidden dangers may exist.

• Patients or bystanders may act to protect you from danger, such as refusing entry or signaling distress, which can indicate underlying threats like violence.

• Effective communication and teamwork are crucial; signaling your crew and calling for help can prevent escalation and ensure everyone's safety.

• Sometimes, you must make difficult decisions to retreat from a scene if it is too dangerous, even if it means not immediately helping the patient.

• Every situation is unique and may require balancing the urge to help with the need to protect yourself and your team, as personal safety must come before patient care in hazardous situations.

Think Like an EMT

• Scene safety is the top priority before providing care; always assess for immediate dangers such as fire, violence, or hazardous conditions before approaching a patient.

• In situations like a car fire, active shooting, or stabbing, consider factors such as your ability to safely access the patient, the presence of ongoing threats, and whether you have the necessary equipment to protect yourself.

• Standard Precautions (Body Substance Isolation) are essential to prevent transmission of infectious diseases between you and the patient. This includes using personal protective equipment (PPE) like gloves, masks, and eyewear when there is a risk of exposure to blood, saliva, or other body fluids.

• PPE should be worn before any patient contact, especially in cases involving bleeding, coughing, or sneezing, and when performing procedures like suctioning or mouth-to-mouth ventilation.

• For airborne diseases (e.g., tuberculosis), use an N-95 or HEPA respirator to filter out infectious particles.

• Always have PPE readily accessible and evaluate the need for additional precautions throughout the call to minimize exposure risks.

• Infection control is mutual; you can transmit infections to the patient as well, so consistent use of Standard Precautions protects both parties.

Nature of the Call

• Scene safety and Standard Precautions must be addressed first before patient assessment.

• Identifying the nature of the call involves determining either the mechanism of injury or the patient's illness.

• Mechanism of injury refers to the physical force or event that causes injury, such as rapid deceleration in a car crash leading to knee injuries, or a fall on ice resulting in a twisted ankle.

SCAN 11-2

• Mechanism of injury refers to the force, its intensity, and direction that caused an injury, and understanding it helps predict injury patterns and severity.

• Types of force include direct, twisting, forced flexion/hyperextension, and indirect, each associated with specific injury sites (e.g., direct blows to the clavicle or scapula, twisting injuries to joints and long bones).

• Injuries are often linked to specific situations: falls and vehicle collisions commonly cause bone and joint injuries; burns are associated with fires; penetrating injuries with gunshots or stabbings.

• Mechanism of injury is a guide, not a guarantee—serious injuries can occur even with minor mechanisms, and vice versa; actual assessment and vital signs are crucial.

• Motor-vehicle collisions involve three collisions: the vehicle striking an object, the body striking the vehicle interior, and internal organs striking body surfaces, each contributing to injury.

• Airbags and restraint systems reduce injury but can also cause harm (e.g., abrasions, fractures, or turning objects into projectiles); airbags deploy only once and may not protect in subsequent impacts.

• Patterns of injury in vehicle collisions depend on the type of impact:

  • Head-on: up-and-over (head, neck, chest, abdomen) or down-and-under (knees, legs, hips) injury patterns.

  • Rear-end: common neck and head injuries due to whiplash.

  • Side-impact (T-bone): injuries to neck, head, chest, abdomen, pelvis, and thighs.

  • Rollover: multiple impacts and possible ejection, leading to varied and severe injuries.

  • Rotational: multiple impacts from spinning and secondary collisions.

• Clues from vehicle damage (e.g., steering wheel, dash, windshield) help identify likely injuries and whether the patient was a driver or passenger.

• Motorcycle and ATV crashes are high risk due to minimal protection; helmet use and ejection status are important factors.

• Falls: injury severity depends on height, landing surface, body part impacted, and interruptions during the fall; energy is transmitted along the body, causing injuries beyond the initial impact site.

• A fall from greater than 10 feet is considered significant, but all scene factors and patient assessment findings must be considered.

• Penetrating trauma is classified by the velocity of the object: low-velocity (e.g., knives) usually cause localized injury, but movement of the object can damage multiple organs.* Bullets cause damage in two main ways: direct tissue destruction from the projectile itself and pressure-related damage (cavitation) from the energy wave created as the bullet enters the body. The bullet’s path is unpredictable due to possible deflection by bones or tissues, and fragmentation can increase the extent of injury.

• Blunt-force trauma results from non-penetrating impacts (e.g., being struck by a bat or hitting a steering wheel), which can cause serious internal injuries, organ rupture, hemorrhage, or spillage of organ contents, even if external signs are minimal or delayed.

• Identifying the mechanism of injury is crucial for anticipating possible internal injuries, especially when external signs are absent. Always maintain a high index of suspicion based on the mechanism, as even minor incidents can cause significant trauma.

• National trauma triage guidelines prioritize anatomic and physiologic criteria (such as penetrating injuries, skull or spinal injuries, unstable chest wall, pelvic fractures, multiple long bone fractures, mangled extremities, amputations, active bleeding, altered mental status, abnormal vital signs) over mechanism of injury for determining transport to trauma centers.

• Red criteria indicate high risk for serious injury and require transport to the highest-level trauma center available. These include specific injuries, vital sign abnormalities, and inability to follow commands.

• Yellow criteria indicate moderate risk based on mechanism of injury (e.g., high-risk auto crashes, significant falls, ejections, need for extrication, telemetry data, or special considerations like anticoagulant use, child abuse suspicion, pregnancy, or burns with trauma). Patients meeting yellow but not red criteria should be transported to a trauma center as available.

• For medical patients, identifying the nature of illness involves gathering information from the patient, family, bystanders, and the scene itself (such as medications or living conditions), especially when the patient is unconscious or disoriented. Use all available information to guide assessment and care.

Number of Patients and Adequacy of Resources

• Always assess if you have enough resources to manage the situation at the scene. If there are multiple patients or the potential for more, request additional ambulances or personnel immediately.

• Actively look for clues indicating additional patients, such as other passengers, pedestrians, or bystanders who may be involved but not immediately obvious.

• Recognize that seemingly routine calls can quickly escalate and require more resources. Examples include: a second patient at a medical call, a bariatric patient in a difficult location, multiple family members with similar symptoms (suggesting a hazardous environment), or multiple births.

• Call for help as soon as you identify the need, since delays can make it harder for additional resources to arrive in time.

• Anticipate the maximum number of patients and request resources accordingly, following local protocols and procedures.

Think Like an EMT

• Scene size-up is essential for safety and effective response; it involves assessing hazards, determining the number of patients, and identifying the need for additional resources.

• For a vehicle accident in an ice storm (18-wheeler in a ditch), you should check for vehicle stability, risk of further sliding, hazardous materials, and access routes.

• In a multi-vehicle collision (van and passenger car on interstate), look for traffic hazards, fuel leaks, number of patients, and scene control needs.

• At an office building with panicked people and a bloody individual, assess for ongoing threats (e.g., violence), crowd control, and the safety of entry points.

• When responding to a residence with a reported natural gas smell, prioritize evacuation, risk of explosion, and coordination with fire department for scene safety.

• At a construction site fall, evaluate for falling debris, unstable structures, and the need for specialized rescue equipment.