1. Initial clinical assessment - rapid ABCDE assessment, history, examination, recognition of deterioration.
2. Airway and respiratory monitoring - airway patency, work of breathing, oxygenation, ventilation, blood gases, chest examination.
3. Cardiovascular assessment - perfusion, shock, fluid status, ECG, invasive/non-invasive blood-pressure monitoring, cardiac output.
4. Neurological assessment - consciousness, pupils, GCS/sedation assessment, delirium, seizures.
5. Renal, metabolic and temperature monitoring - urine output, fluid balance, electrolytes, glucose, acid-base state, temperature.
6. Infection and sepsis surveillance - examination for source, cultures, lactate, organ dysfunction trends.
7. Lines, devices, skin and nutrition - checking vascular access, ventilator settings, drains, pressure injuries, enteral feeding.
8. Trend-based interpretation and documentation - escalation triggers, frequency of observations, communicating change using structured handover.

ABCDE assessment of the critically ill patient

• A - Airway
• B - Breathing
• C - Circulation
• D - Disability
• E - Exposure / Environment

Exception: If the patient has catastrophic external haemorrhage, control it immediately before or alongside airway management. In suspected trauma, protect the cervical spine while managing the airway.

Core principles before starting

1. Ensure safety: use appropriate PPE; consider hazards to patient, staff, and others.
2. Recognise critical illness quickly: observe appearance, skin colour, posture, work of breathing, and conscious level. Ask an awake patient, “How are you?” A normal verbal response suggests a patent airway, breathing, and cerebral perfusion at that moment.
3. Call for help early: senior clinician, critical-care/outreach team, anaesthesia, emergency team, or trauma team according to setting.
4. Start monitoring simultaneously: pulse oximetry, ECG, non-invasive blood pressure, respiratory rate, temperature, and if available capnography.
5. Use a team: one person assesses while others obtain IV/IO access, prepare oxygen, take bloods, obtain medications, and document.
6. Address life-threatening findings before moving forward.
7. Use trends, not isolated values: deterioration in respiratory rate, oxygen need, mental status, urine output, lactate, or perfusion may precede hypotension or cardiac arrest.
8. If cardiac arrest is present: activate resuscitation response and begin CPR according to current life-support guidance rather than completing ABCDE first.

A - Airway

Question

Assess

• Facial, oral, neck, or upper-airway trauma
• Blood, vomitus, secretions, foreign material, loose teeth, dentures
• Tongue obstruction, swelling of tongue/lips, burns, soot, drooling
• Paradoxical chest-abdominal movement or reduced consciousness
• Signs of impending obstruction: agitation, inability to speak, cyanosis, exhaustion

• Snoring or gurgling: tongue or secretions
• Stridor: upper-airway narrowing, potentially rapidly progressive
• Hoarseness, muffled voice, weak cough
• Silence in a patient making visible respiratory effort: may indicate complete obstruction

• Air movement at mouth and nose
• Consider neck swelling or surgical emphysema where relevant

• Conscious level and ability to manage secretions
• Cough and gag where appropriate
• Vomiting or aspiration risk
• Rapidly declining GCS or loss of protective reflexes

Immediate management

• Position the patient appropriately. Use head tilt-chin lift if no concern for cervical trauma.
• If trauma or possible cervical-spine injury: use manual in-line stabilization and jaw thrust. Do not let cervical precautions delay life-saving airway opening.
• Suction secretions, blood, or vomitus.
• Remove only visible, easily retrievable foreign material. Do not perform blind finger sweeps.
• Give high-concentration oxygen if critically unwell.
• Use an airway adjunct if trained and appropriate:
  • Oropharyngeal airway in an unconscious patient without an intact gag reflex
  • Nasopharyngeal airway when appropriate, but avoid if suspected basal skull fracture or major mid-face trauma
• Prepare early for definitive airway management if airway patency or protection is uncertain:
  • Call anaesthesia/critical care
  • Prepare bag-mask ventilation, suction, capnography, intubation equipment, and a rescue airway plan
  • Anticipate a difficult airway and have a surgical-airway rescue pathway where relevant

Red flags requiring immediate escalation

• Stridor, rapidly increasing facial/neck swelling, inhalational injury
• Inability to speak, silent airway obstruction, or copious secretions
• Reduced consciousness with loss of airway protection
• Recurrent vomiting or aspiration
• Anticipated difficult airway or failed basic airway manoeuvres

B - Breathing

Question

Assess

1. Observe the patient

• Respiratory rate, depth, rhythm, and pattern
• Ability to speak: full sentences, short phrases, single words, or unable to speak
• Work of breathing: accessory-muscle use, tracheal tug, nasal flaring, intercostal recession, abdominal breathing
• Chest expansion and symmetry
• Cyanosis, sweating, agitation, drowsiness, fatigue
• Position: sitting upright, tripod position, inability to lie flat
• Devices: oxygen delivery system, flow rate, ventilator settings, tubing, disconnections, alarms, chest drains

2. Measure

• SpO₂ and oxygen delivery device/flow or FiO₂
• Respiratory rate
• End-tidal CO₂ if available, especially in intubated, sedated, or ventilated patients
• Arterial or venous blood gas where indicated:
  • pH
  • PaCO₂: ventilation
  • PaO₂ / oxygenation
  • HCO₃⁻ and base excess
  • lactate
• Peak airway pressures and tidal volumes in ventilated patients

3. Examine the chest

• Inspect chest wall injury, asymmetry, wounds, drain sites
• Palpate tracheal position, chest expansion, tenderness, surgical emphysema
• Percuss:
  • Hyper-resonance may indicate pneumothorax
  • Dullness may indicate pleural fluid, blood, or consolidation
• Auscultate both lungs:
  • Reduced/absent unilateral breath sounds: pneumothorax, effusion, mainstem intubation, collapse
  • Wheeze: bronchospasm
  • Crackles: pulmonary oedema, pneumonia, atelectasis
  • Bronchial breathing: consolidation

Consider immediately reversible causes

• Upper-airway obstruction
• Bronchospasm/asthma or COPD exacerbation
• Pneumothorax, especially tension pneumothorax
• Pulmonary oedema
• Pneumonia, aspiration, ARDS
• Pulmonary embolism
• Pleural effusion or haemothorax
• Opioid/sedative-induced hypoventilation
• Ventilator or oxygen-equipment failure

Immediate management

• Give oxygen, titrated to the clinical context:
  • Most critically ill patients initially require high-concentration oxygen.
  • In patients at risk of hypercapnic respiratory failure, oxygen should still not be withheld in critical illness, but saturation targets and blood gases should be reviewed promptly.
• Sit the patient upright if compatible with their condition.
• Correct simple problems: reconnect oxygen/ventilator circuit, relieve tube kinking, check mask fit, suction if required.
• Assist ventilation with bag-mask ventilation if inadequate spontaneous ventilation, while preparing definitive airway support.
• Treat cause:
  • Nebulised bronchodilator for bronchospasm where indicated
  • Needle decompression followed by chest drainage for suspected tension pneumothorax, without waiting for imaging if unstable
  • Non-invasive ventilation or invasive ventilation only with appropriate expertise and monitoring
  • Treat pulmonary oedema, infection, embolism, or aspiration according to the clinical diagnosis

Red flags

• Severe distress, exhaustion, reduced consciousness
• “Silent chest,” stridor, or unilateral absent breath sounds
• Rising CO₂, worsening acidosis, falling SpO₂ despite oxygen
• Sudden hypotension with respiratory distress: consider tension pneumothorax or massive pulmonary embolism
• Any worsening after intubation: check tube position, ventilator circuit, pneumothorax, and haemodynamic consequences

C - Circulation

Question

Assess

• Skin colour: pale, mottled, cyanosed, flushed
• Sweating, peripheral shutdown
• External haemorrhage, surgical drains, wound bleeding
• Distended neck veins, oedema
• Signs of fluid loss: vomiting, diarrhoea, burns, polyuria
• Urine output and fluid-balance chart

• Central and peripheral pulse rate, rhythm, volume
• Peripheral temperature: warm or cold
• Capillary refill time, interpreted in context of ambient temperature, age, and vasopressor use
• Skin mottling and limb perfusion

• Blood pressure, repeated frequently or invasively if indicated
• Continuous ECG monitoring
• Heart rate and rhythm
• Urine output, usually measured with a catheter in the unstable critically ill patient
• Blood gas and lactate
• Blood tests as clinically indicated: FBC, U&E, creatinine, glucose, coagulation tests, group-and-save/crossmatch, troponin, cultures

• Heart sounds, murmurs
• Lung signs of pulmonary oedema
• Abdomen for distension, tenderness, rigidity, pulsatile mass, concealed bleeding
• Pelvis and long bones in trauma
• Legs for DVT signs when relevant
• Bedside ultrasound/echo, where trained personnel and equipment are available, may rapidly identify cardiac dysfunction, pericardial fluid, major intravascular-volume abnormalities, intra-abdominal free fluid, or pneumothorax.

Think of shock by mechanism

Immediate management

• Control catastrophic external haemorrhage:
  • Direct pressure, haemostatic dressing, tourniquet where appropriate
  • Activate major-haemorrhage protocol when indicated
  • Warm the patient and blood products
• Obtain two large-bore IV cannulas. If this is delayed or impossible, use intraosseous access in an emergency.
• Draw urgent bloods during cannulation.
• Give a carefully assessed fluid bolus when hypovolaemia is likely, then reassess perfusion and signs of fluid overload.
• For haemorrhagic shock, prioritize rapid haemorrhage control and blood-component resuscitation rather than repeated large volumes of crystalloid.
• Start vasopressors only with appropriate expertise, monitoring, and attention to likely cause of shock. They do not substitute for fluid resuscitation or source control where these are needed.
• Obtain and interpret an ECG promptly for arrhythmia, ischaemia, or electrolyte-related changes.
• Insert urinary catheter when clinically appropriate to measure output accurately.

Red flags

• Persistent systolic hypotension or rapidly falling BP
• New tachyarrhythmia/bradyarrhythmia with instability
• Mottling, cold peripheries, delayed capillary refill, oliguria
• Lactate rising or metabolic acidosis worsening
• Active bleeding, suspected internal haemorrhage
• Suspected tamponade, tension pneumothorax, or massive pulmonary embolism

D - Disability

Question

Assess

• Use AVPU for rapid assessment:
  • A - Alert
  • V - responds to Voice
  • P - responds to Pain
  • U - Unresponsive
• Use Glasgow Coma Scale (GCS) for serial, detailed assessment, documenting eye, verbal, and motor components.
• For sedated/intubated patients, document sedation level and the limitation of verbal scoring.

• Size, symmetry, reactivity to light
• New fixed/dilated pupil or anisocoria may suggest intracranial pathology, but check for drugs, eye injury, or pre-existing differences.

• New focal weakness, facial asymmetry, speech disturbance
• Seizure activity or post-ictal state
• Agitation, delirium, confusion, headache, meningism
• Posture and motor response

• Glucose: test immediately in altered consciousness, seizures, unexplained deterioration, or shock
• Oxygenation and ventilation: hypoxaemia and hypercapnia can reduce consciousness
• Drugs: opioids, sedatives, alcohol, toxins
• Electrolyte disorders, especially sodium, calcium, and magnesium
• Temperature
• Sepsis, hepatic/renal encephalopathy, intracranial bleeding, stroke, trauma

Immediate management

• Correct hypoxaemia and inadequate ventilation first.
• Check bedside glucose and treat hypoglycaemia promptly according to local protocol.
• Treat active seizures using an emergency seizure pathway, support airway/breathing, and seek urgent senior help.
• Consider naloxone for suspected clinically significant opioid toxicity, while maintaining ventilation and observing for recurrent toxicity.
• Protect the airway if consciousness is impaired.
• Urgent neuroimaging and specialist input are needed for suspected acute stroke, intracranial haemorrhage, significant head injury, new focal deficit, or unexplained coma.

Red flags

• Falling GCS/AVPU score
• New focal neurological deficit
• Seizures or persistent post-ictal depression
• Unequal or non-reactive pupils
• Agitation progressing to drowsiness, especially with hypoxia, hypercapnia, sepsis, or raised intracranial pressure

E - Exposure and environment

Question

Assess

• Temperature, including trend
• Skin colour, rashes, petechiae/purpura, urticaria, cellulitis, pressure damage
• Full body for bleeding, wounds, burns, bruising, surgical sites, drains, stomas
• Abdomen, back, groin, perineum, and limbs as clinically indicated
• Leg swelling/asymmetry, calf tenderness, ischaemia
• Signs of infection or source control problem: line sites, catheter site, wounds, drains
• Fluid balance, nutrition, pressure-area risk
• Medication chart, allergies, recent procedures, transfusion history, and relevant devices

Immediate management

• Treat hypothermia: warm blankets, warmed fluids/blood where appropriate, warm environment.
• Treat hyperthermia while identifying its cause.
• Cover the patient once examination is complete.
• Reposition and provide pressure-area care when stable enough.
• Maintain dignity and use a chaperone for intimate examination when possible.
• Check lines, drains, tubes, and devices for position, patency, infection, or complications.

Reassessment and ongoing monitoring

1. What was abnormal?
2. What intervention was given?
3. Did the patient improve objectively?
4. What remains the likely underlying cause?
5. What level of care is required now?

Minimum monitoring in an unstable patient

• Continuous SpO₂
• Continuous ECG
• Frequent or continuous BP monitoring
• Respiratory rate and work of breathing
• Conscious level
• Temperature
• Urine output and fluid balance
• Serial blood gases, lactate, electrolytes, and glucose when indicated
• Capnography for intubated or deeply sedated patients, and where clinically appropriate during procedural sedation

Escalation and communication

• Situation: who the patient is and what is happening now
• Background: diagnosis, key history, treatment, ceiling of care
• Assessment: ABCDE findings, vital-sign trends, blood gas/lactate, response to treatment
• Recommendation: what help is required now, for example review, intubation, vasopressors, imaging, transfer to ICU

• Time of deterioration and observations
• ABCDE findings
• Interventions and doses/fluids/blood given
• Response and repeat observations
• Who was contacted and agreed plan
• Ongoing review frequency and escalation ceiling

One-line examination answer

“I would ensure safety, call for help, apply monitoring, and perform a structured ABCDE assessment. I would treat any life-threatening abnormality immediately before progressing, reassess after every intervention, seek the underlying cause, communicate using SBAR, document findings and response, and escalate to critical care if instability persists.”