On-call isn’t rare diagnoses.

It’s the same 20 problems… again and again.

Most bleeps fall into predictable patterns.

If you learn how to handle these confidently, 80% of your shift becomes much easier.

This guide focuses on:

👉 What you’ll actually get bleeped about at 2am — and what to do first

Not theory.
Not long differentials.
Just safe, practical action.

How to use this page

For any bleep:

Always:

1️⃣ Ask for observations
2️⃣ Get NEWS
3️⃣ Decide urgency
4️⃣ A–E at bedside
5️⃣ Treat first, diagnose later

Then use the quick guides below.

🔴 “Doctor, NEWS is high / patient looks unwell”

What this usually means

Undifferentiated deterioration.

Could be:

sepsis
hypoxia
bleeding
dehydration
anything

Treat as sick until proven otherwise.

What to do immediately

Go now
Full A–E
Oxygen
IV access
Bloods
Fluids if hypotensive
Escalate early

Common mistake

Trying to diagnose before stabilising.

🔴 “BP low” / Hypotension

Think first

Shock until proven otherwise.

Common causes:

sepsis
bleeding
dehydration
meds
cardiac

What to do

A–E
Repeat manual BP
2 IV cannulas
Bloods + lactate
Fluid bolus
Check meds
Escalate if not improving

Red flags

SBP < 90 or not responding to fluids → call senior early

🔴 “Chest pain”

Think first

ACS until proven otherwise.

What to do

ECG immediately
obs
oxygen if needed
IV access
troponin
aspirin (if appropriate)
senior review

Never miss

ECG first, not bloods first

Time = myocardium

🟠 “Short of breath / low sats”

Common causes

pneumonia
COPD
PE
pulmonary oedema
asthma

What to do

A–E
oxygen
ABG if unwell
chest exam
CXR
treat cause (neb/diuretics/antibiotics)

Escalate if

Increasing oxygen needs or tiring

🟠 “Confused / delirious”

Think first

Delirium = underlying medical problem

Often:

infection
hypoxia
retention
constipation
meds
metabolic

What to do

A–E
glucose
urine check
bloods
review meds
treat cause

Common mistake

Calling psych before ruling out medical causes

🟠 “Temp 38.5 / ?sepsis”

Think first

Early sepsis until proven otherwise

What to do

A–E
Sepsis 6
blood cultures
antibiotics early
fluids
lactate
monitor closely

Golden rule

Antibiotics early > perfect diagnosis later

🟠 “Low urine output”

Common causes

dehydration
AKI
obstruction
sepsis

What to do

check fluid balance
bladder scan
bloods/U&E
fluids if dry
review meds
catheter if needed

Escalate if

Rising creatinine or persistent oliguria

🟠 “Glucose low/high”

Hypo

give glucose immediately
don’t wait

Hyper/DKA suspicion

ketones
VBG
start protocol
senior early if severe

Common mistake

Delaying treatment for labs

🟢 “Need cannula / bloods / fluids”

What to do

ask urgency
batch jobs by ward
don’t interrupt sick patient reviews

These are routine tasks unless unstable.

🟢 “Rewrite drug chart / TTO / discharge summary”

Reality

Admin, not emergency

Safe to delay

Night shift = patient safety, not paperwork perfection

Do last

🔴 “I’m worried about this patient”

This phrase is very important.

If an experienced nurse says this:

Treat as RED.

Even if obs look okay.

Clinical intuition from nurses is often very accurate.

Go see them.

Pattern you’ll notice

Most bleeps fit into:

airway/breathing
circulation
infection
confusion
pain
admin

Very few are rare or complex.

Confidence comes from handling these basics well.

Senior mindset

Good on-call doctors don’t memorise rare diagnoses.

They:

recognise sick early
use A–E
treat basics fast
escalate early

Same structure every time.

Simple. Safe. Effective.

Take-home concept

On-call medicine isn’t about being clever.

It’s about being systematic.

If you handle common bleeps calmly and consistently, the whole shift feels manageable.

Master the basics and 80% of nights become straightforward.

Rare problems are rare.

Common problems are common.

Be excellent at common.