2.4 Secondary Assessment, SAMPLE & Vitals by Age
Key Takeaways
- Secondary assessment includes a SAMPLE history and a focused head-to-toe exam after life threats are addressed
- SAMPLE stands for Signs/Symptoms, Allergies, Medications, Past medical history, Last meal/liquids, and Events leading to the illness or injury
- Normal heart rate, respiratory rate, and blood pressure change substantially with age—use age-based ranges rather than adult defaults
- Hypotension is a late sign in many pediatric shock states; teach age-based systolic thresholds including the 70 + (2 × age in years) rule for ages 1–10
- Capillary refill, urine output, and indicated diagnostics support serial reassessment but never replace the evaluate–identify–intervene loop
When secondary assessment begins
The secondary assessment happens after immediate life threats from the PAT and primary ABCDE survey are controlled—or it runs in parallel when enough trained helpers are present. You never postpone CPR, airway opening, or treatment of respiratory failure to finish a perfect history.
Secondary assessment has three practical parts:
- SAMPLE history
- Focused physical examination
- Vital signs and adjuncts (including age-based interpretation, capillary refill, urine output, and indicated tests)
SAMPLE history
SAMPLE is the standard PALS history mnemonic:
| Letter | Meaning | High-yield pediatric questions |
|---|---|---|
| S | Signs and symptoms | Onset of breathing difficulty, fever, vomiting, lethargy, rash, trauma pain |
| A | Allergies | Medications, foods, latex; prior anaphylaxis |
| M | Medications | Home meds, recent steroids/inhalers, anticoagulants, possible ingestions |
| P | Past medical history | Prematurity, congenital heart disease, asthma, seizures, technology dependence (trach/vent/G-tube) |
| L | Last meal / last liquids | Aspiration risk; timing for procedures; hypoglycemia risk in infants who have not fed |
| E | Events leading up to present illness/injury | Choking episode, known ingestion, submersion, progressive illness over hours/days |
History sources: caregivers, EMS, medical alert jewelry, medication bottles, and—when appropriate—the child. For non-accidental trauma concerns, document carefully and follow mandatory reporting rules without delaying resuscitation.
Focused physical examination
After ABCDE, expand the exam based on the working identification:
- Head/neck: trauma, JVD (limited utility in infants), tracheal deviation, meningismus signs if relevant.
- Chest: injuries, equal breath sounds, heart murmurs/gallops (cardiogenic clues).
- Abdomen: distention, peritonitis signs, organomegaly (hepatomegaly can support cardiogenic shock or fluid overload after boluses).
- Skin: rashes (petechiae/purpura), burns, hydration (skin turgor—interpret cautiously), perfusion.
- Neuro: more detailed mental status, focal deficits, fontanelle in infants.
- Extremities: deformity, pulses distal to injury, edema.
Reassess any abnormal primary findings after each intervention.
Vital signs by age (typical PALS teaching ranges)
Pediatric vital signs are age-dependent. Using adult "normal" values is a classic error. The numbers below are widely used PALS/teaching approximations for study purposes; institutional references and the current AHA provider materials may present slightly different tables, and clinical judgment always incorporates the whole picture (fever, pain, crying, and chronic baseline).
Heart rate (approximate awake rates)
| Age group | Typical awake HR (beats/min) | Clinical notes |
|---|---|---|
| Neonate (0–28 days) | ~100–205 | Sleeping rates lower; persistent bradycardia is ominous |
| Infant (1–12 months) | ~100–180 | Sinus tachycardia common with fever/dehydration |
| Toddler (1–2 years) | ~98–140 | Fear/pain elevate rate |
| Preschool (3–5 years) | ~80–120 | |
| School-age (6–12 years) | ~75–118 | |
| Adolescent | ~60–100 | Approaches adult norms |
Bradycardia in a child is often secondary to hypoxia until proven otherwise—support oxygenation and ventilation first. Heart rate <60/min with poor perfusion is a CPR trigger (primary assessment rule).
Respiratory rate (approximate normal ranges)
| Age group | Typical RR (breaths/min) |
|---|---|
| Neonate / infant | ~30–60 (infants often taught ~30–53 in some tables) |
| Toddler | ~22–37 |
| Preschool | ~20–28 |
| School-age | ~18–25 |
| Adolescent | ~12–20 |
Count for a sufficient interval in quiet children when possible; interpret rate with effort and air entry. A "normal" rate with extreme retractions is still abnormal physiology. A falling rate in a tiring asthmatic may signal impending failure, not recovery.
Blood pressure and hypotension thresholds (teaching rules)
Blood pressure requires a properly sized cuff (bladder width ~40% of mid-upper-arm circumference is a common teaching target). Hypotension definitions used widely in PALS teaching:
| Age | Systolic BP suggesting hypotension (approximate teaching thresholds) |
|---|---|
| Term neonate (0–28 days) | <60 mm Hg |
| Infants (1–12 months) | <70 mm Hg |
| Children 1–10 years | <70 + (2 × age in years) mm Hg |
| Children >10 years | <90 mm Hg |
Example: A 4-year-old hypotensive threshold ≈ 70 + (2×4) = 78 mm Hg systolic. A 4-year-old with SBP 82 mm Hg may still be in compensated shock if perfusion signs are poor—do not wait for hypotension to treat shock.
Compensated vs hypotensive shock reminder: children maintain blood pressure with intense vasoconstriction and tachycardia until late. Abnormal appearance, prolonged CRT, weak pulses, and cool/mottled skin can indicate shock with a "normal" BP.
Capillary refill and urine output
| Parameter | Typical teaching expectation | Use in PALS |
|---|---|---|
| Capillary refill | Often ≤2 seconds centrally when warm and well perfused | Serial marker of systemic perfusion; interpret with ambient temperature and the whole exam |
| Urine output | Often cited goal ~1 mL/kg/h in children (infants may be higher, e.g., ~1.5–2 mL/kg/h in some teaching references) | Useful during ongoing resuscitation/post-stabilization; not available in the first seconds of care |
Neither parameter alone rules shock in or out. Rising urine output after fluids supports improving renal perfusion; anuria with ongoing hypotension demands continued aggressive management and cause search.
Diagnostic tests as indicated
Order tests that change management, not a shotgun panel that delays care:
- Point-of-care glucose early with altered mental status.
- Pulse oximetry and cardiac monitoring as soon as available in sick children.
- ETCO2 when bagging or with advanced airway—ventilation quality and, during CPR, a marker of quality/ROSC trends (do not use a single low ETCO2 alone to stop resuscitation).
- ECG for arrhythmia evaluation when pulse is present and rhythm diagnosis matters.
- Blood gas, lactate, electrolytes, CBC, cultures, imaging based on the identified problem (sepsis, trauma, respiratory failure, metabolic crisis).
- Length-based tape / weight estimate for drug and energy dosing when weight is unknown.
Putting secondary assessment into the loop
Secondary findings refine identify without abandoning evaluate–identify–intervene:
- SAMPLE reveals known adrenal insufficiency → shock plan includes stress-dose steroid consideration per protocol.
- Exam shows hepatomegaly and crackles after fluids → reconsider cardiogenic physiology; slow fluids and support blood pressure carefully.
- Vitals show HR 220 in an infant with poor perfusion → identify unstable tachycardia pathway rather than simple fever tachycardia.
- BP falls below age threshold during observation → reclassify compensated shock as hypotensive shock and escalate.
Exam-style practice items to self-check
- Math check: 7-year-old SBP threshold ≈ 70 + 14 = 84 mm Hg. An SBP of 88 with cool mottled extremities can still be shock.
- History check: A toddler with sudden coughing/cyanosis while eating → events history points to foreign-body airway obstruction even if SAMPLE allergies are negative.
- Rate check: Adolescent RR 14 may be normal; the same rate in a neonate is apnea-range pathology.
Common traps
- Treating every tachycardic child as SVT without comparing rate to age norms and clinical context (fever, pain, dehydration).
- Declaring a child "stable" solely because BP is above the hypotension line.
- Forgetting glucose in the secondary/disability workup.
- Inventing false precision—remember that published tables vary slightly; PALS expects age-aware interpretation and the standard hypotension formulas, not memorization of every research percentile curve.
When you can take a SAMPLE history efficiently, perform a focused exam, and correctly label HR/RR/BP as normal, abnormal, or prearrest for the child's age, you complete the assessment foundation used in every later PALS algorithm chapter.
What does the "L" in SAMPLE history represent?
Using standard PALS teaching thresholds, which systolic blood pressure is at the approximate hypotension cutoff for a 5-year-old child?
A school-age child has tachycardia, cool mottled extremities, capillary refill of 4 seconds, and altered interactiveness, but systolic blood pressure is still above the age-based hypotensive threshold. What is the best interpretation?