01Purpose and principlesWhat the assessment is for and the core concepts behind it.
The Paediatric Assessment Triangle converts the doorway impression into three explicit observations. Appearance includes tone, interaction, consolability, look or gaze and speech or cry. Work of breathing includes abnormal sounds, positioning, recession, nasal flaring and visible effort. Circulation to skin includes pallor, mottling and cyanosis. Observe before oxygen, restraint or crying changes the picture. A normal triangle is reassuring only for that moment and does not exclude early sepsis, ingestion or evolving intracranial disease.
PAT patterns guide priority. Isolated abnormal breathing with normal appearance and circulation is respiratory distress. When appearance becomes abnormal, respiratory failure is developing. Isolated abnormal circulation suggests compensated shock; abnormal appearance alongside it suggests decompensated shock. Abnormal appearance alone can reflect neurological, metabolic or toxic disease. Abnormality in all three indicates cardiopulmonary failure. These labels mobilise resources while ABCDE defines treatable life threats.
Airway assessment asks whether air moves freely and whether the child can vocalise. Listen for snoring, gurgling and stridor and look for recession or paradoxical movement. Open with head position and chin lift or jaw thrust; infants' large occiput may flex the neck when supine, so use a neutral position with shoulder support if needed. Suction visible secretions and remove only a clearly visible obstruction. Use age-sized adjuncts and early anaesthetic or paediatric help when patency is threatened.
Breathing assessment combines rate, pattern, chest expansion, effort, air entry, added sounds, oxygen saturation and mental state. A high rate with recession can progress to slower irregular effort as fatigue develops; apparent improvement with reduced alertness is dangerous. Give high-concentration oxygen in critical illness, while targeted saturation ranges apply after stabilisation to selected conditions. Use bag-mask ventilation with an appropriate mask and rate when ventilation is inadequate, watching chest rise and avoiding excessive pressure or gastric inflation.
Circulatory assessment recognises compensation before hypotension. Tachycardia, cool peripheries, prolonged capillary refill, weak peripheral pulses and reduced urine can occur while central blood pressure remains maintained. Compare central and peripheral pulses, measure blood pressure with a correctly sized cuff and interpret in context. Control external bleeding. Obtain IV access, but move promptly to intraosseous access when shock is severe and venous attempts delay treatment. Send glucose, gas, lactate, FBC, culture and cause-directed tests without delaying resuscitation.
Fluid is a treatment trial, not a fixed sequence. Current UK paediatric emergency guidance uses 10 mL/kg isotonic crystalloid aliquots for shock with immediate reassessment of heart rate, perfusion, mental state, breathing, hepatomegaly and lung signs. In sepsis, seek senior or critical-care help early when repeated boluses are needed. Haemorrhage needs early blood and source control. Cardiogenic shock may worsen with rapid fluid and needs smaller, specialist-directed aliquots and vasoactive support.
Disability includes consciousness, pupils, tone, posture, focal signs, seizure, pain and glucose. AVPU is rapid; a detailed age-adjusted Glasgow Coma Scale follows when needed. A child responding only to pain or unresponsive has a threatened airway. Check glucose early because hypoglycaemia is reversible and can mimic sepsis, seizure or brain injury. Treat ongoing convulsive seizure by the paediatric emergency algorithm and consider ingestion, trauma, infection and metabolic disease.
Exposure requires enough undressing to find the cause while actively preventing heat loss. Inspect the entire skin for non-blanching rash, urticaria, injury, burns, swelling, bleeding and device problems. Palpate abdomen and assess limbs, back and fontanelle when relevant. Measure temperature with an age-appropriate method. Preserve dignity, use a chaperone and consider safeguarding if injury distribution or explanation is concerning. Replace clothes and warming promptly.
Reassessment is the engine of ABCDE. After airway positioning, confirm air movement; after ventilation, confirm chest rise, heart rate and saturation; after fluid, reassess perfusion and signs of overload; after glucose or anticonvulsant, reassess consciousness. Record time, intervention, dose and response. A child who transiently improves and deteriorates again has not completed resuscitation and needs renewed A-to-E review and senior escalation.
Parallel tasks improve safety: one clinician leads ABCDE, one monitors and records, one establishes access and prepares medicines and one obtains focused history. Use closed-loop communication and state weight, allergies and calculated doses aloud. Involve parents when this calms the child and ask about baseline behaviour, but give them a clear safe role during procedures. Escalate early because paediatric airway, vascular access and drug calculations become harder after physiological collapse.
Key points
- The Paediatric Assessment Triangle is a no-equipment first look at appearance, work of breathing and circulation to skin, completed in seconds before hands-on ABCDE.
- PAT identifies a physiological pattern and urgency; it does not provide a diagnosis, replace observations or delay resuscitation.
- Abnormal work of breathing with preserved appearance suggests respiratory distress; abnormal appearance as effort fails suggests respiratory failure.
- Abnormal skin circulation with preserved appearance suggests compensated shock; abnormal appearance or hypotension indicates decompensation.
- Start ABCDE with airway patency and position; use neutral positioning in infants and slight extension in older children while protecting the cervical spine when indicated.
- For breathing, assess rate, effort, air entry, chest movement, saturation and signs of exhaustion; give oxygen and assist ventilation when effort is inadequate.
- For circulation, assess heart rate, central and peripheral pulses, capillary refill, skin temperature, blood pressure, urine and mental state; obtain IV or intraosseous access according to urgency.
- Give a 10 mL/kg isotonic crystalloid bolus for paediatric shock under current UK pathways, reassess immediately and use smaller or cautious aliquots in cardiac or renal disease.
- For disability, assess AVPU or Glasgow Coma Scale, pupils, posture, seizure and bedside glucose; treat hypoglycaemia and seizures promptly.
- For exposure, examine fully while preserving dignity and temperature, looking for rash, injury, bleeding, swelling, medical devices and safeguarding findings.
- Treat each life threat when found rather than completing the alphabet first, and repeat ABCDE from the beginning after every intervention or deterioration.
- Use weight in kilograms, age-adjusted equipment and independent dose checks; if weight is unavailable in a true emergency, use an approved length-based system.
02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.
Increased effort or abnormal sounds with preserved interaction and skin circulation suggests compensation that can still deteriorate rapidly.
Exhaustion, poor air entry, cyanosis, irregular breathing or reduced responsiveness indicates inadequate oxygenation or ventilation.
Tachycardia, cool mottled skin, weak peripheral pulses and prolonged refill occur before blood pressure necessarily falls.
Abnormal appearance, weak central pulses, hypotension or bradycardia marks late circulatory failure and peri-arrest risk.
Abnormal appearance without primary breathing or skin-circulation signs directs early glucose, neurological and toxicological assessment.
Abnormality across appearance, breathing and circulation signals immediate resuscitation-team activation and simultaneous ABC support.
03Method and interpretationA systematic approach to the test and its findings.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
First-line: Paediatric Assessment TriangleFirst stepFirst line - Why
- Identify severity and physiological domain within seconds without touching the child.
- Interpretation and limitations
- Classify appearance, breathing and skin circulation separately; any abnormal domain accelerates hands-on ABCDE and monitoring.
- 02
First-line: continuous observationsFirst line - Why
- Track oxygenation, heart rate, respiratory rate, blood pressure, temperature and consciousness.
- Interpretation and limitations
- Use age-adjusted ranges and trends; a falling heart or respiratory rate during exhaustion may represent deterioration rather than recovery.
- 03
Bedside glucose and blood gas - Why
- Detect reversible hypoglycaemia and measure ventilation, acid-base disturbance, lactate and electrolytes.
- Interpretation and limitations
- Treat low glucose immediately; rising lactate or worsening acidosis supports impaired perfusion but is interpreted with clinical response.
- 04
Cause-directed blood tests and cultures - Why
- Identify infection, anaemia, metabolic disturbance and organ dysfunction after initial stabilisation.
- Interpretation and limitations
- Sampling must not delay antibiotics or other time-critical treatment in a high-risk child.
- 05
Focused imaging - Why
- Define pneumonia, pneumothorax, trauma, obstruction or intracranial pathology when findings warrant.
- Interpretation and limitations
- Use bedside imaging when transfer is unsafe; imaging never precedes treatment of an immediately reversible life threat.
- 06
Repeated documented ABCDE - Why
- Determine whether each intervention improved physiology and expose new priorities.
- Interpretation and limitations
- Failure to improve or recurrent abnormality triggers senior, critical-care and cause-specific escalation rather than repeated identical treatment.
04Clinical next stepsHow the result changes management or prompts escalation.
01Doorway assessmentPAT before contactFirst stepA child is first seen in any acute setting.+
- 1Observe appearance, work of breathing and circulation to skin without disturbing the child.
- 2Name the physiological pattern and decide whether resuscitation-team activation is immediate.
- 3Move directly to hands-on ABCDE, monitoring and age-appropriate equipment when any domain is abnormal.
02Airway or breathing threatOxygenate and ventilate earlyAirway noise, poor air movement, hypoxaemia, exhaustion or reduced consciousness is present.+
- 1Position and open the airway, suction visible secretions and give high-concentration oxygen for critical illness.
- 2Use airway adjuncts and bag-mask ventilation with chest-rise assessment when ventilation is inadequate.
- 3Call senior airway and critical-care support early and reassess airway, chest movement, heart rate and saturation after each action.
03ShockAccess, aliquot and reassessPerfusion is abnormal through pulse, refill, skin, consciousness, urine or blood pressure.+
- 1Control bleeding, obtain IV or prompt intraosseous access, check glucose and send cause-directed samples.
- 2Give 10 mL/kg isotonic crystalloid when appropriate, or early blood for haemorrhage, with caution for cardiac or renal disease.
- 3EscalationReassess immediately for perfusion response and fluid overload and escalate early for repeated boluses or vasoactive support.
04Reduced consciousnessProtect airway and reverse causesAVPU is abnormal, a seizure continues or neurological status falls.+
- 1Re-open airway, support oxygenation and ventilation and check bedside glucose immediately.
- 2Treat hypoglycaemia or seizure through the weight-based emergency algorithm and assess pupils, trauma and focal signs.
- 3Seek urgent paediatric, anaesthetic and neurological or toxicological support and repeat neurological observations.
05After interventionReturn to AAny airway, breathing, circulation or neurological treatment has been delivered.+
- 1Repeat the entire ABCDE rather than checking only the treated variable.
- 2Record intervention, dose, time, physiological response and any adverse effect.
- 3EscalationEscalate level of care if improvement is incomplete, short-lived or dependent on intensive support.
05Risks, monitoring and follow-upComplications, safety checks and further assessment.
- Use continuous pulse oximetry and ECG in critical illness, cycling blood pressure at a frequency appropriate to instability.
- Record respiratory effort and air entry alongside saturation because oxygen can normalise saturation without correcting ventilation or exhaustion.
- After every fluid aliquot, document heart rate, refill, pulses, blood pressure, consciousness, urine, respiratory signs and liver enlargement.
- Repeat glucose after treatment and during ongoing altered consciousness, sepsis, liver disease or prolonged poor intake.
- Trend PEWS and individual observations, but escalate on clinical concern even if an aggregate score remains below a threshold.
- During transfer or handover, state current ABC support, weight, access, cumulative fluids, medicines, allergies and the last response explicitly.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
PAT is deliberately visual
Touching a frightened child can change crying, pulse, respiratory effort and colour before the first-look physiology is captured.
Hypotension is late
Children maintain blood pressure through vasoconstriction and tachycardia, so normal pressure does not exclude clinically important shock.
Falling effort can be worse
A tiring child may become quieter and breathe more slowly as respiratory failure develops, creating false reassurance.
Intraosseous access is timely
It is a rapid vascular route for fluids and emergency medicines when repeated venous attempts would prolong severe shock.
Oxygen does not equal ventilation
Supplemental oxygen can improve saturation while carbon dioxide rises, making effort, air entry and consciousness essential monitoring.
Reassessment tests the diagnosis
The direction and durability of response to position, ventilation, fluid or glucose help refine physiology while treatment continues.
07Common pitfallsFrequent interpretation and management errors.
- 01
Do not treat PAT as a substitute for hands-on ABCDE and observations.
- 02
Do not finish a full examination before treating an airway or breathing threat.
- 03
Do not interpret quieter breathing as improvement when alertness and air entry are falling.
- 04
Do not wait for hypotension before recognising paediatric shock.
- 05
Do not persist with repeated peripheral cannulation attempts during severe shock instead of using intraosseous access.
- 06
Do not give serial fluid boluses without documented reassessment for response and overload.
- 07
Do not use an estimated weight when an accurate recent weight is available and time permits verification.
- 08
Do not expose the child for examination without preventing hypothermia and preserving dignity.
- 09
Do not hand over a score alone without the concerning signs and trajectory that produced it.