2.1 Pediatric Assessment Triangle (PAT)

Why the PAT matters on the PALS exam

Pediatric cardiac arrest is usually the end stage of progressive respiratory failure or shock, not a sudden primary coronary event. That pathophysiologic difference is why PALS places so much weight on early recognition. The Pediatric Assessment Triangle (PAT) is the first formal step of the systematic approach: a hands-off, from-the-doorway impression that takes roughly 30–60 seconds and answers the operational question, "Is this child sick or not sick?"

You form the PAT before you touch the patient, place a pulse oximeter, or start a full set of vitals. The purpose is not to replace the primary assessment; it is to set urgency, call for help early, and decide whether you need immediate life-support interventions while a fuller exam continues.

The PAT has three sides (sometimes called "legs"):

1. Appearance
2. Work of breathing
3. Circulation to the skin

Each side can be normal or abnormal. Combinations of abnormal sides map to major physiologic categories (respiratory, circulatory, or both/cardiopulmonary failure) and prepare you for the evaluate–identify–intervene loop covered in the next section.

Appearance: the "TICLS" features

Appearance is the most important single side of the PAT for predicting serious illness. A child can still look "alert" early in compensated shock, but a clearly abnormal appearance is a red flag that the brain is not receiving adequate oxygen or perfusion.

Use the TICLS mnemonic to structure what you see and hear:

Exam traps related to appearance:

• A quiet infant who is not crying may look "good" to an inexperienced provider but may be obtunded—always interpret quietness with tone and gaze.
• Agitation can be a sign of hypoxia; do not dismiss a combative child as "just scared" without checking work of breathing and oxygenation.
• Developmental baseline matters: a nonverbal child with known disability is judged against their baseline, not a typical peer.

Work of breathing

Work of breathing is a visual and auditory assessment of how hard the child is working to move air. It is not the same as counting the respiratory rate (rate comes later in the hands-on primary assessment). Abnormal work of breathing suggests a respiratory problem and often appears before oxygen saturation falls.

Look and listen for four classic findings:

1. Abnormal airway sounds — stridor (upper airway), wheezing (lower airway), grunting (often a sign of significant lower-airway or lung disease; the child is trying to create positive end-expiratory pressure), snoring (partial upper-airway obstruction, including depressed consciousness), or muffled voice ("hot potato" voice with possible peritonsillar/epiglottic pathology).
2. Abnormal positioning — tripoding, refusal to lie flat, head bobbing in infants, sniffing position, or the child insisting on sitting upright in a caregiver's arms.
3. Retractions — suprasternal, intercostal, subcostal, or sternal; the younger the child, the more compliant the chest wall and the more dramatic retractions can appear.
4. Nasal flaring — especially useful in infants who are obligate nasal breathers; flaring means the child is recruiting accessory efforts to increase airflow.

Important distinctions:

• Increased work of breathing with relatively preserved appearance often means respiratory distress (still compensating).
• Decreased effort with poor appearance (slow or shallow breathing, quiet chest) may mean respiratory failure or impending arrest—the child is tiring out, not "improving."
• Absent breath sounds on one side with severe distress can signal pneumothorax, foreign body, or mainstem issues; that finding belongs to the hands-on exam but your doorway impression may already show extreme work of breathing or cyanosis.

Circulation to the skin

Circulation to the skin is a visual estimate of perfusion using skin color—not blood pressure, not capillary refill (those are hands-on). Skin findings that matter on the PAT:

Caveats the exam likes to test:

• Cold extremities alone are common in febrile children who are vasoconstricted; interpret color with appearance and work of breathing, not in isolation.
• Cyanosis may be hard to see in children with darker skin tones—inspect lips, tongue, and mucous membranes, and do not wait for dramatic blue skin before acting on other PAT abnormalities.
• A child with pure compensated hypovolemic shock may still have a relatively normal appearance early, but pallor or mottling often appears as a warning.

Combining the three sides: sick vs not sick

Think of the PAT as a traffic light for urgency:

Key teaching point: You do not need a complete set of vital signs to declare a child sick. A limp, poorly interactive infant with retractions and mottling is already in a high-urgency category. Conversely, a playful toddler with normal color and effort who is crying vigorously is usually not sick on general impression—even if the parent is very anxious.

How PAT drives the next 60 seconds of care

Once you form the PAT impression:

1. Call for help / activate resources proportional to how sick the child looks (additional clinicians, airway equipment, monitor/defibrillator, length-based tape).
2. Do not delay life-saving interventions for a perfect history. If the PAT shows severe distress or failure, begin oxygen, positioning, and support while the primary assessment starts.
3. Hand off a clear general impression to the team: for example, "PAT shows abnormal appearance and work of breathing—treat as respiratory emergency."
4. Move immediately into the hands-on primary assessment (ABCDE) and the continuous evaluate–identify–intervene sequence.

Scenario practice (exam-style thinking)

• Scenario A: A 2-year-old sits on a parent's lap, cries loudly when you approach, reaches for a toy, has no retractions, and has pink skin. PAT: all sides essentially normal → not sick on general impression → complete primary assessment and focused history without panic interventions.
• Scenario B: A 6-month-old is limp, does not track your face, has nasal flaring and intercostal retractions, and looks mottled. PAT: abnormal appearance, work of breathing, and circulation → cardiopulmonary failure risk → high-flow oxygen/support ventilation readiness, rapid primary survey, prepare for possible CPR if pulse/HR and perfusion collapse.
• Scenario C: A 4-year-old is interactive and pink but sits tripod, drooling, with audible stridor. PAT: abnormal work of breathing (and possibly speech/cry), relatively preserved circulation → upper-airway emergency → keep the child calm, do not force supine exam or oropharyngeal inspection that may worsen obstruction, prepare advanced airway expertise.

Master the PAT vocabulary—TICLS, the four work-of-breathing findings, and pallor/mottling/cyanosis—because PALS written items and megacode scenarios repeatedly start with a doorway impression before any algorithm branch.