Delay and Deterioration
Understanding what happens physiologically when intervention is delayed — the countdown your casualty is on
Why Understand Deterioration?
Knowing what to do is one skill. Understanding why timing matters is another. When you understand how the body fails, you’ll recognize the urgency and make faster decisions.
The Core Insight: Every minute of delay has physiological consequences. Deterioration is predictable — and so is prevention.
Hemorrhage: The Clock is Running
What Happens
The human body contains approximately 5 liters of blood. Here’s what happens as it’s lost:
| Blood Loss | Effect |
|---|---|
| 15% (~750ml) | Anxiety, slight heart rate increase |
| 15-30% (~1500ml) | Tachycardia, confusion, pale skin |
| 30-40% (~2000ml) | Severe tachycardia, hypotension, altered consciousness |
| Over 40% (~2000ml+) | Loss of consciousness, imminent death |
A severed femoral artery can lose 1 liter per minute. You have 2-3 minutes before irreversible shock begins.
The Cascade
- Blood loss → Decreased oxygen delivery
- Decreased oxygen → Cells switch to anaerobic metabolism
- Anaerobic metabolism → Lactic acid buildup
- Acidosis → Coagulation dysfunction (blood can’t clot)
- More bleeding → Accelerating cycle
This is the lethal triad: hypothermia, acidosis, coagulopathy. Once established, it’s extremely difficult to reverse.
The Implication
Every second without hemorrhage control pushes the casualty further into the cascade. A tourniquet at 0 minutes saves a life. At 5 minutes, you’re fighting uphill.
Airway Obstruction: Minutes to Brain Death
What Happens
Without oxygen, brain cells begin dying in 4-6 minutes. Survival is possible up to about 10 minutes, but with increasing neurological damage.
Common causes in trauma:
- Tongue relaxation in unconscious casualties
- Blood or vomit in the airway
- Facial/neck injuries
- Swelling from burns or allergic reaction
The Timeline
| Time Without Oxygen | Effect |
|---|---|
| 0-1 minute | Anxiety, increased breathing effort |
| 1-3 minutes | Confusion, cyanosis (blue skin) |
| 4-6 minutes | Loss of consciousness, brain damage begins |
| 6-10 minutes | Severe brain damage, death likely |
The Implication
Airway obstruction is immediately visible (or audible). If the casualty is making abnormal sounds, struggling, or turning blue — you have minutes to act. A simple NPA or positioning change can be the difference.
Tension Pneumothorax: Pressure Kills
What Happens
A chest wound can act as a one-way valve: air enters the chest cavity but can’t escape. Pressure builds with each breath.
- Air accumulates in the pleural space
- Pressure collapses the injured lung
- Pressure shifts the heart and great vessels
- Venous return to the heart is impeded
- Cardiac output falls → Shock → Death
The Timeline
Tension pneumothorax can kill in minutes. Unlike hemorrhage, you can’t see it happening externally until late signs appear.
Progressive signs:
- Increasing respiratory distress
- Decreasing breath sounds on affected side
- Hypotension
- Tracheal deviation (very late)
- Distended neck veins (may not be visible if hypovolemic)
The Implication
Any penetrating chest injury can develop tension pneumothorax. A chest seal that doesn’t vent can cause tension pneumothorax. Monitor. Reassess. Be ready to decompress.
Hypothermia: The Slow Killer
What Happens
Trauma casualties lose heat from:
- Blood loss (warm blood leaving the body)
- Exposure (wet clothing, ground contact, wind)
- Decreased metabolism (shock reduces heat production)
- IV fluids (room temperature fluids are cold relative to body temp)
Core temperature doesn’t have to drop much to cause problems:
| Core Temp | Effect |
|---|---|
| 36°C (96.8°F) | Shivering begins |
| 35°C (95°F) | Coagulation impaired |
| 34°C (93.2°F) | Severe coagulopathy, cardiac irritability |
| Below 32°C (89.6°F) | Risk of cardiac arrest |
The Cascade
Hypothermia feeds back into the lethal triad:
- Cold → Coagulopathy → More bleeding
- More bleeding → Less oxygen delivery → Less heat production
- Less heat → Worsening hypothermia
The Implication
Hypothermia prevention isn’t a “nice to have” — it’s essential to survival. A casualty kept warm has better clotting, better cardiac function, and better outcomes. Cover them early and often.
Head Injury: Secondary Damage
What Happens
Primary brain injury occurs at the moment of impact. You can’t undo it.
Secondary brain injury occurs afterward and is preventable:
- Hypoxia (low oxygen) → More brain cells die
- Hypotension (low blood pressure) → More brain cells die
- Hypoglycemia (low blood sugar) → More brain cells die
- Increased intracranial pressure → More brain cells die
The Implication
With head injury, your job is preventing secondary damage:
- Maintain airway and oxygenation
- Maintain blood pressure (normal targets, not permissive hypotension)
- Avoid anything that increases intracranial pressure
- Expedite evacuation
The Bottom Line
Every component of MARCH exists because delay causes predictable, progressive harm:
| Delay In… | Leads To… |
|---|---|
| Hemorrhage control | Irreversible shock, lethal triad |
| Airway management | Brain death |
| Treating pneumothorax | Cardiovascular collapse |
| Shock treatment | Organ failure |
| Hypothermia prevention | Coagulopathy, worse outcomes |
Understanding deterioration isn’t about fear — it’s about informed urgency. When you know what’s at stake, you act faster and with more conviction.
Takeaway: Time is tissue. The best intervention is the one performed now.