Vital Signs

Why vital signs matter

Vital signs are the cheapest early-warning system in nursing. A patient deteriorates in the numbers before they deteriorate in appearance. The skill being tested is rarely "what is normal" — it is noticing a trend and acting on it.

Record the number, then ask two questions every time: is this different from this patient's baseline, and is this moving in one direction over several readings.

Normal adult ranges

Sign	Normal adult range	Escalate when
Temperature	36.5–37.5 °C	> 38.0 °C or < 35.0 °C
Heart rate	60–100 bpm	< 50 or > 120
Respiratory rate	12–20 breaths/min	< 8 or > 24
Blood pressure	~120/80 mmHg	Systolic < 90 or > 180
SpO₂	95–100 %	< 92 % on room air

Ranges shift with age, pregnancy, and chronic disease. A COPD patient may live at 88–92 % and that is their normal.

Respiratory rate is the one people skip

Respiratory rate is the most sensitive early indicator of deterioration and the most frequently estimated rather than counted. Count for a full 30 seconds and double it. Do it while you still appear to be taking the pulse — telling a patient you are counting their breathing changes their breathing.

A rising respiratory rate with everything else still normal is often the first sign of sepsis, and it is the single most commonly missed cue.

Order of assessment

1. General appearance from the doorway — colour, work of breathing, position
2. Respiratory rate
3. Pulse — rate, rhythm, strength
4. Blood pressure
5. Temperature
6. SpO₂
7. Pain

Common errors that change the number

• Cuff too small — falsely high blood pressure
• Arm below heart level — falsely high
• Patient just walked in — rest five minutes before recording
• Cold fingers or nail polish — unreliable SpO₂
• Talking during BP — falsely elevated

Escalate

Escalate on a pattern, not a single reading. Report using SBAR: the number, the baseline, the trend, and what you have already done.