Unit 2: Primary Assessment
Circulation, Shock, & Immediate Interventions
A weak pulse, severe bleeding, or sudden change in mental status may indicate that a patient’s circulatory system is failing. EMTs must recognize these warning signs quickly and take action before the patient’s condition deteriorates. This section of our NREMT study guide explains circulation, tissue perfusion, shock, and emergency bleeding control. You’ll also find five EMT practice questions with answer explanations to reinforce the essential concepts.
The circulatory system transports oxygen and nutrients throughout the body and removes waste products from tissues. When circulation becomes inadequate, vital organs may not receive enough oxygen to function properly.
During the primary assessment, EMTs must identify circulation problems, recognize signs of shock, and treat immediate life threats.
Assessing Circulation
Circulation is assessed by evaluating the patient’s pulse, skin condition, mental status, and signs of significant bleeding.
Pulse
A pulse provides information about the patient’s heart rate, rhythm, and circulation.
Common pulse assessment sites include:
- Radial pulse: Located at the wrist and commonly assessed in responsive patients.
- Carotid pulse: Located in the neck and commonly used to assess circulation in unresponsive adults.
- Brachial pulse: Located on the inner upper arm and commonly used when assessing an infant.
A normal resting adult pulse is generally 60–100 beats per minute.
A rapid, weak pulse may indicate inadequate circulation, while an absent pulse in an unresponsive patient who is not breathing normally indicates cardiac arrest.
Skin Condition
Skin temperature, moisture, and color provide clues about circulation.
Signs of poor perfusion may include:
- Pale or unusually discolored skin.
- Cool, clammy skin.
- Excessive sweating.
- Delayed capillary refill, particularly in children.
Skin findings must be interpreted alongside other assessment results because temperature, lighting, and natural skin pigmentation can affect their appearance.
Mental Status
The brain requires a continuous supply of oxygenated blood. Confusion, restlessness, or decreasing responsiveness may indicate inadequate cerebral perfusion.
A sudden change in mental status should always raise concern for a serious medical condition.
Understanding Perfusion and Shock
Perfusion is the delivery of oxygenated blood to the body’s tissues.
Shock occurs when the circulatory system cannot provide adequate tissue perfusion to meet the body’s needs.
Without adequate perfusion, cells become deprived of oxygen and nutrients, and organs may begin to fail.
Shock can develop from several different causes, including blood loss, heart failure, infection, and severe allergic reactions.
Types of Shock
EMTs should recognize the major categories of shock.
Hypovolemic Shock
Hypovolemic shock occurs when the body loses a significant amount of blood or fluid.
Common causes include:
- Severe external or internal bleeding.
- Extensive burns.
- Severe vomiting or diarrhea.
- Significant dehydration.
Shock caused by blood loss is called hemorrhagic shock.
Cardiogenic Shock
Cardiogenic shock occurs when the heart cannot pump enough blood to meet the body’s needs.
It may result from a severe heart attack or other serious cardiac conditions.
Distributive Shock
Distributive shock occurs when abnormal blood vessel dilation interferes with effective circulation.
Examples include:
- Septic shock: Caused by a severe infection.
- Anaphylactic shock: Caused by a severe allergic reaction.
- Neurogenic shock: Associated with disruption of nervous system control of blood vessels, often following spinal cord injury.
Obstructive Shock
Obstructive shock occurs when a physical obstruction prevents blood from circulating effectively.
Possible causes include tension pneumothorax, cardiac tamponade, and massive pulmonary embolism.
Recognizing the Stages of Shock
Shock may progress through compensatory and decompensatory stages.
Compensated Shock
During compensated shock, the body attempts to maintain blood flow to vital organs by increasing heart rate and constricting blood vessels.
Common signs include:
- Increased heart rate.
- Increased respiratory rate.
- Pale, cool, or clammy skin.
- Anxiety or restlessness.
- Weakening peripheral pulses.
Blood pressure may remain normal during this stage.
Decompensated Shock
As shock worsens, the body can no longer maintain adequate circulation.
Signs may include:
- Falling blood pressure.
- Weak or difficult-to-detect pulses.
- Significant alterations in mental status.
- Increasingly ineffective breathing.
- Loss of consciousness.
Low blood pressure is often a late sign of shock. EMTs must recognize earlier warning signs rather than waiting for hypotension to develop.
Not every type of shock produces the same findings. For example, neurogenic shock may cause a slower heart rate and warm, dry skin rather than the typical signs of compensated hypovolemic shock.
Controlling External Bleeding
Severe external bleeding is an immediate life threat and must be controlled as soon as it is identified.
EMTs use several methods to control bleeding.
Direct Pressure
Apply firm, continuous pressure directly over a bleeding wound using sterile gauze or an appropriate dressing.
If a dressing is not immediately available, a gloved hand can be used to apply direct pressure.
Tourniquets
A tourniquet is used to control life-threatening bleeding from an arm or leg.
Apply a commercial tourniquet according to manufacturer instructions and EMS protocols, generally 2–3 inches above the wound and not directly over a joint.
Tighten the tourniquet until the bleeding stops, and document the application time.
For clearly life-threatening extremity hemorrhage, apply a tourniquet promptly rather than delaying effective bleeding control.
Wound Packing
Deep wounds in areas where a tourniquet cannot be applied, such as the groin or armpit, may require wound packing with appropriate gauze followed by firm pressure.
Use hemostatic dressings when available and authorized by local protocols.
Internal Bleeding
Internal bleeding occurs when blood is lost into body cavities or tissues rather than outside the body.
Possible signs include:
- Abdominal pain or tenderness.
- Abdominal swelling or rigidity.
- Bruising around an injured area.
- Signs of shock without obvious external bleeding.
- A mechanism of injury suggesting significant internal trauma.
Unlike external bleeding, internal bleeding generally cannot be controlled directly by EMTs in the field.
Patients with suspected serious internal bleeding require rapid assessment, appropriate supportive care, and prompt transport to a suitable medical facility.
Emergency Care for Shock
Treatment focuses on supporting circulation, addressing the underlying cause when possible, and preventing further deterioration.
Important interventions include:
- Maintain an open airway and support breathing as needed.
- Control life-threatening external bleeding.
- Administer supplemental oxygen when indicated.
- Position the patient appropriately, generally lying flat if tolerated and not contraindicated by injury or breathing difficulty.
- Prevent unnecessary heat loss by covering the patient with a blanket.
- Request Advanced Life Support (ALS) when appropriate.
- Arrange prompt transport and reassess the patient’s condition frequently.
Do not give food or drinks to a patient experiencing shock.
Specific treatments depend on the cause. For example, anaphylaxis may require epinephrine according to EMS protocols, while hemorrhagic shock requires rapid bleeding control and appropriate transport.
Key Tip
Do not wait for a patient’s blood pressure to fall before suspecting shock. A rapid pulse, increased breathing rate, altered mental status, and cool, clammy skin may be early warning signs. Recognize these findings, treat immediate life threats, and arrange prompt transport.