Big Sick or Little Sick? A First Aid Assessment Guide

A Fast and Focused Way to Assess Casualties

At RealMed First Aid there’s one idea we always come back to:

Big Sick or Little Sick? — a rapid, intuitive approach to assessing a casualty.

This model isn’t just for beginners. It’s used by everyone from new First Aiders to Consultant Anaesthetists. It helps you make fast decisions by asking: "Is it normal?"

🚨 Common Mistake: Judging by Injuries

We’re hardwired to react to blood and visible trauma. But remember:

• Big injuries ≠ Big Sick

• Small injuries ≠ Little Sick

A person may have a serious-looking injury and still be "Little Sick" — stable and not dying. Another may have no visible injury but be pale, struggling to breathe, and likely to deteriorate fast. That’s Big Sick.

👁️ Vital Signs: Your Guide to "Normal"

When someone tells you they feel "unwell," or they’re unconscious, how do you judge if they’re in serious trouble?

Use the 5 Basic Vital Signs to assess:

1. Level of Response (AVPU)

2. Breathing

3. Colour

4. Temperature

5. Capillary Refill

🔎 1. Level of Response (AVPU)

Instead of just asking "Are they conscious?" — use AVPU:

• A - Alert

  • Knows where they are, what’s happening, speaks clearly.

• V - Responds to Voice

  • Groans, flinches, or mumbles when you talk to them.

• P - Responds to Pain

  • Reacts only when you apply gentle but real pain (e.g., jaw pressure).

• U - Unresponsive

  • No reaction to voice or pain.

If they’re not Alert, that’s not normal, and that’s bad.

🧐 2. Breathing: Not Just "Yes or No"

Don’t just ask "Are they breathing?" — instead, assess how they are breathing:

• Rate — Too fast? Too slow?

• Effort — Are they struggling?

• Depth — Shallow or deep?

• Rhythm — Irregular?

• Noise — Wheezing, gurgling, rasping?

Any abnormal breathing = Big Sick

💅 3. Colour: Trust Your Eyes

Skin colour is a key visual clue:

• Pale — Blood is being pulled to the core. Shock, blood loss, or oxygen shortage.

• Blue (cyanosis) — Dangerously low oxygen.

• Red — Could be exercise or fever. Ask: "Is it normal for the situation?"

• Yellow — Jaundice.

• Green — Yep, they might actually look green before vomiting!

Note: In darker skin tones, check conjunctiva (eyes) or nail beds for colour changes.

🌡️ 4. Temperature: Feel It

No thermometer? Use your hands like Mum used to:

• Feel their forehead, neck, chest.

• Ask: "Is this temperature normal for the weather, activity, or clothing?"

For more accurate monitoring (especially in illness or hypothermia), consider using:

• Tympanic (ear) thermometer — most accurate

• Infrared forehead thermometer — small, easy

⏰ 5. Capillary Refill: Fast and Simple

Forget the pulse. Capillary refill is easier:

• Press on the forehead or sternum for 5 seconds

• Let go. Does colour return within 2 seconds?

🔹 If yes = Normal 

🔹 If delayed = Could indicate shock or blood loss 

🔹 If instantaneous = Too much blood at skin surface (sepsis, anaphylaxis, head injury)

Note: On darker skin, press and observe the fingernail instead.

🎥 Quick Case Study

Imagine a casualty:

• Only responds to voice (not alert)

• Breathing is noisy and deep

• Skin looks pale

That’s 3 abnormal signs. That’s Big Sick — even if you don’t know what’s wrong yet.

📱 If calling emergency services, be specific:

• Instead of "They’re conscious and breathing"

• Say: "They respond to voice, their breathing is noisy, and they look pale."

This helps professionals make better decisions faster.

✅ Wrap Up: Ask "Is it normal?"

Use this checklist every time:

• ✉️ Alert?

• 💨 Breathing?

• 💅 Colour?

• 🌡️ Temperature?

• ⏰ Capillary Refill?

🤔 If it’s not normal, it’s bad. That’s Big Sick.

📍 We Come to You
RealMed First Aid delivers interactive, group first aid courses across New Zealand. Our hands-on, scenario-based training builds real confidence for real emergencies.