Why the A-E Assessment Is the Most Important Clinical Framework You'll Learn
The A-E (Airway, Breathing, Circulation, Disability, Exposure) assessment is the systematic approach to any acutely unwell patient. It appears in OSCEs as a simulated emergency station, in acute medicine ward calls, in A&E, and in resuscitation scenarios. More importantly, it is the framework that will keep your patients safe on the wards from the first day of your foundation year.
The A-E approach works because it prioritises life-threatening problems in order of how quickly they will kill the patient. Airway obstruction kills in minutes; sepsis kills in hours. Treat each problem as you find it — don't move to B until A is secured.
💡 Tip
The single most important habit: Call for help early. In an OSCE, saying "I would call for senior support and ask for a crash trolley to be brought to the bedside" within the first 30 seconds of a deteriorating patient scenario scores marks and reflects safe clinical practice. Struggling alone is not heroic — it is dangerous.
Before You Start — The 30-Second Approach
- 1Introduce yourself and confirm the patient's identity
- 2General impression — look at the patient from the door. Do they look well or about to arrest?
- 3Ask the patient — "How are you feeling?" A confused response, no response, or agitation tells you immediately this is serious
- 4Call for help if you are concerned: "I would call 2222 for the crash team / bleep the registrar"
- 5Request monitoring: "I would attach pulse oximetry, continuous cardiac monitoring, and automated BP"
- 6Establish IV access and take blood cultures, FBC, U&E, LFTs, coagulation, glucose, lactate, and a VBG if not already done
A — Airway
Goal: Is the airway patent? If not, open it.
Assess:
- Look: Is the chest moving? Any cyanosis?
- Listen: Any stridor (harsh inspiratory noise = partial upper airway obstruction), gurgling (secretions/fluid), or silence?
- Feel: Air movement at the mouth and nose
Findings and responses:
| Finding | Intervention |
|---|---|
| Patent airway, patient talking | Reassess; move to B |
| Snoring (tongue obstruction) | Head-tilt chin-lift or jaw thrust; consider airway adjunct |
| Gurgling (fluid/secretions) | Suction; recovery position if unconscious and breathing |
| Stridor (partial obstruction) | Call for anaesthetics/senior immediately; prepare for emergency intubation |
| Silent, no movement | Complete obstruction — call arrest team; begin BLS |
⚠️ Red Flag
Never perform a blind finger sweep in a suspected foreign body obstruction. In a conscious adult who is choking, give up to 5 back blows followed by up to 5 abdominal thrusts (Heimlich manoeuvre). If they become unconscious, begin CPR.
Airway adjuncts:
- Nasopharyngeal airway (NPA): soft rubber tube inserted into the nostril — better tolerated in semi-conscious patients; contraindicated in suspected base of skull fracture
- Oropharyngeal airway (Guedel): rigid plastic tube inserted into the mouth — only tolerated in unconscious patients; insert upside down, rotate 180° into position
B — Breathing
Goal: Is ventilation adequate? Is there a life-threatening respiratory cause?
Assess (in this order):
- 1Respiratory rate — the most sensitive early marker of deterioration. Normal: 12–20/min. Rate >25 = concerning; >30 = critical
- 2Oxygen saturations — normal ≥95%; in known COPD, target 88–92%
- 3Inspection — chest movement symmetric? Use of accessory muscles? Tracheal position?
- 4Palpation — tracheal deviation, chest expansion
- 5Percussion — dull (consolidation/effusion) vs hyperresonant (pneumothorax/emphysema)
- 6Auscultation — air entry bilaterally, added sounds
💎 Clinical Pearl
RR is the most underused vital sign. Studies consistently show that a rising respiratory rate is the first vital sign to deteriorate in ward patients heading for ICU admission. If the patient is breathing faster than 20, take it seriously.
Life-threatening B emergencies and their signs:
| Emergency | Signs | Immediate action |
|---|---|---|
| Tension pneumothorax | Tracheal deviation away, absent breath sounds, hypotension, raised JVP | Needle decompression — 2nd ICS, MCL — do not wait for CXR |
| Massive haemothorax | Dull to percussion, absent breath sounds, haemodynamic compromise | Senior/thoracics; chest drain |
| Acute severe asthma | Silent chest, use of accessory muscles, SpO₂ <92%, unable to speak | High-flow O₂, back-to-back salbutamol nebs, IV hydrocortisone, call ITU |
| Pulmonary oedema | Bibasal crackles, frothy sputum, elevated JVP, orthopnoea | Sit upright, high-flow O₂, IV furosemide, GTN if BP allows |
Oxygen prescribing:
- Target SpO₂ 94–98% for most patients
- Target SpO₂ 88–92% for patients with known hypercapnic (type 2) respiratory failure
- Use 15L/min via non-rebreather mask if the patient is critically unwell
C — Circulation
Goal: Is there adequate tissue perfusion? Is there haemodynamic compromise?
Assess:
- 1Heart rate — normal 60–100. Tachycardia is a non-specific but sensitive sign of shock
- 2Blood pressure — systolic <90 mmHg is hypotension; MAP <65 = shock
- 3Capillary refill time (CRT) — press the finger pad for 5 seconds; >2 seconds = reduced peripheral perfusion
- 4Skin — cold/clammy = shock; warm/vasodilated = sepsis or anaphylaxis
- 5Urine output — should be >0.5 ml/kg/hr; catheterise if not already done
- 6JVP — raised in cardiac failure/tamponade; flat in hypovolaemia
Types of shock — distinguish them:
| Type | HR | BP | CRT | JVP | Skin | Causes |
|---|---|---|---|---|---|---|
| Hypovolaemic | ↑ | ↓ | ↑ | ↓ | Cold, pale | Haemorrhage, dehydration |
| Septic | ↑ | ↓ | Variable | ↓ | Warm, vasodilated | Infection |
| Cardiogenic | ↑ | ↓ | ↑ | ↑ | Cold, pale | MI, arrhythmia, tamponade |
| Anaphylactic | ↑ | ↓ | ↑ | ↓ | Flushed, urticaria | Allergen exposure |
| Neurogenic | ↓ | ↓ | ↑ | ↓ | Warm | Spinal cord injury |
🧠 Mnemonic
Sepsis Six (within 1 hour of suspected sepsis):
- 1Oxygen — high flow if SpO₂ <94%
- 2Blood cultures — before antibiotics
- 3Antibiotics — IV broad spectrum (e.g. piperacillin-tazobactam + gentamicin per local protocol)
- 4Fluids — 500ml IV crystalloid bolus if hypotensive
- 5Lactate — serum lactate (>2 = elevated; >4 = severe)
- 6Urine output — catheterise and monitor hourly
Mnemonic: O BAF LU — "Oh BAFL you!"
IV fluid resuscitation:
- Give 500ml 0.9% NaCl or Hartmann's over 15 minutes
- Reassess after each bolus — does HR fall? Does BP rise? Does CRT improve?
- In cardiogenic shock, fluid is potentially harmful — be cautious; involve senior
D — Disability
Goal: What is the neurological status? Is there a CNS cause?
Assess:
- 1AVPU scale — quick and reliable:
- Alert
- Voice — responds to voice
- Pain — responds to pain only
- Unresponsive
*AVPU P or U = GCS ≤8 = consider airway protection*
- 1GCS — if time allows, score Eyes (1–4) + Verbal (1–5) + Motor (1–6) = 3–15
- 1Blood glucose — always check glucose in any unwell patient. Hypoglycaemia (<4 mmol/L) is reversible and rapidly fatal if missed
- 1Pupils — size, equality, reactivity to light
- Fixed, dilated: raised ICP, herniation, or atropine/mydriatics
- Pinpoint: opioid toxicity
- Unequal (anisocoria): herniation, Horner's syndrome, third nerve palsy
- 1Posture — decorticate (flexion) or decerebrate (extension) = severe brain injury
⚠️ Red Flag
Hypoglycaemia mimics almost everything. A patient who appears drunk, agitated, confused, post-ictal, or having a stroke may simply be hypoglycaemic. Check blood glucose in every unwell patient before drawing conclusions. Treatment: 150ml of 10% glucose IV or Glucogel buccally if able to swallow.
E — Exposure
Goal: Is there something being missed on clinical examination?
Expose the patient fully, maintaining dignity:
- Temperature — fever (infection, malignancy) or hypothermia (<35°C)
- Skin — rashes (petechiae = meningococcal; urticaria = anaphylaxis; erythema = cellulitis/NF)
- Wounds and surgical sites — dehiscence, infection, haematoma
- Drains and lines — what is draining, what colour, how much
- Calves — DVT (swollen, warm, tender unilateral calf)
- Abdomen — quickly reassess if C assessment suggests abdominal cause
Escalation — SBAR
After completing your A-E assessment, escalate using SBAR:
| Situation | "I'm calling about [patient name], a [age]-year-old on [ward], who has acutely deteriorated." |
|---|---|
| Background | "They were admitted for [reason] and have a history of [relevant PMH]." |
| Assessment | "On assessment: RR 28, SpO₂ 88%, BP 88/60, HR 124, GCS 14. My impression is septic shock secondary to [source]." |
| Recommendation | "I have started the Sepsis Six and given 500ml IV fluid. I need you to review urgently — can you come now?" |
💡 Tip
Practise SBAR out loud until it is fluent. In an OSCE emergency scenario, calling for help and handing over clearly using SBAR will score marks even if your clinical assessment was imperfect. Communication during a crisis is assessed just as rigorously as the clinical skills.
The NEWS2 Score
The National Early Warning Score 2 (NEWS2) is used across NHS hospitals to standardise the identification of deteriorating patients. It scores 6 physiological parameters:
| Parameter | Score 3 | Score 2 | Score 1 | Score 0 | Score 1 | Score 2 | Score 3 |
|---|---|---|---|---|---|---|---|
| RR | ≤8 | 9–11 | 12–20 | 21–24 | ≥25 | ||
| SpO₂ (Scale 1) | ≤91 | 92–93 | 94–95 | ≥96 | |||
| BP (systolic) | ≤90 | 91–100 | 101–110 | 111–219 | ≥220 | ||
| HR | ≤40 | 41–50 | 51–90 | 91–110 | 111–130 | ≥131 | |
| Consciousness | Alert | CVPU | |||||
| Temperature | ≤35.0 | 35.1–36.0 | 36.1–38.0 | 38.1–39.0 | ≥39.1 |
NEWS2 ≥5 = urgent clinical review. NEWS2 ≥7 = emergency response.
Common Examiner Follow-Up Questions
"You've identified septic shock — what are your immediate priorities?"
"I would initiate the Sepsis Six immediately: high-flow oxygen, blood cultures before antibiotics, IV broad-spectrum antibiotics per local protocol, 500ml crystalloid bolus, serum lactate, and urinary catheter for hourly output. I would alert ITU early and reassess continuously."
"The patient's GCS has dropped from 15 to 10 — what do you do?"
"I would first reassess A and B — is the airway patent and ventilation adequate? I would check blood glucose immediately to exclude hypoglycaemia. I would examine pupils for signs of raised ICP, review medications for sedating drugs, and consider urgent CT head if no reversible cause is found. I would escalate to ITU/anaesthetics regarding airway protection."
"What is the difference between AVPU and GCS?"
"AVPU is a rapid 4-point scale used in the primary survey — it is quick but less granular. GCS is a 15-point scale that scores eyes, verbal, and motor responses separately — it is more precise for monitoring trends in neurological status. AVPU P roughly equates to GCS 8, which is the threshold below which airway protection should be considered."