Vital Signs¶
Category: Core Concepts Sources: UCLA EMT Ultimate Study Guide (2026) Last updated: 2026-05-06 San Juan College EMT-B Program — New Mexico
Overview¶
Vital signs are objective, measurable indicators of a patient's physiologic status. A single set of vital signs is a snapshot. Two sets show a trend. Three sets show a direction — and direction is what drives your transport and treatment decisions.
EMT-B measures six vital signs: blood pressure, pulse, respirations, skin signs, pupils, and oxygen saturation (SpO2). Some sources list five and omit pupils; include all six. Some sources add blood glucose as a 7th — check it in any patient with altered mental status.
The Six Vital Signs¶
1. Blood Pressure (BP)¶
What it measures: the force of blood against arterial walls during ventricular contraction (systolic) and relaxation (diastolic). Recorded as systolic/diastolic in mmHg.
Normal adult: 90–140 mmHg systolic / 60–90 mmHg diastolic. Generally written as < 140/90 for adults at rest.
How to measure: - Auscultated (preferred): Apply cuff 1 inch above antecubital fossa, inflate to 180 mmHg (or 30 mmHg above expected systolic), place stethoscope over brachial artery, slowly deflate (2–3 mmHg/sec). First Korotkoff sound = systolic. Sound disappears = diastolic. - Palpated (backup when auscultation is impossible — noise, motion): Inflate cuff while palpating radial pulse, deflate until pulse returns = systolic. Report as "110 systolic by palpation." Diastolic cannot be determined by palpation.
Abnormal findings: - Hypertension (SBP > 140): Concern for end-organ damage in chronic hypertension; acute severe HTN in pregnancy (pre-eclampsia); elevated after pain or anxiety - Hypotension (SBP < 90): Shock, hemorrhage, dehydration, vasodilation, cardiac failure — always a red flag; priority transport - Narrowing pulse pressure (systolic–diastolic gap <25 mmHg): Early shock, pericardial tamponade - Widening pulse pressure (gap >50 mmHg): Increased intracranial pressure, aortic regurgitation
2. Pulse¶
What it measures: heart rate and rhythm, assessed by palpating an arterial pulse.
Sites: - Radial (wrist): preferred for non-critical patients; reflects peripheral perfusion - Carotid (neck): used in CPR, unconscious patients, or if radial is absent - Brachial (antecubital fossa): used in infants for pulse checks; also for BP auscultation
How to measure: Count for 30 seconds × 2 for regular rhythms. Count for full 60 seconds for irregular rhythms. Note rate, rhythm (regular vs. irregular), and quality (strong vs. weak/thready).
Normal ranges by age:
| Age Group | Normal Pulse Rate (bpm) |
|---|---|
| Adult (> 12 yrs) | 60–100 |
| School-age child (6–12) | 70–110 |
| Preschool (1–5) | 80–120 |
| Infant (< 1 year) | 100–160 |
Abnormal findings: - Bradycardia (< 60 adult): vagal response, heart block, hypothyroidism, medications (beta-blockers), hypoxia — in children, bradycardia is a pre-arrest rhythm; treat immediately - Tachycardia (> 100 adult): pain, fever, dehydration, shock, anxiety, stimulant drugs, cardiac dysrhythmia - Weak/thready pulse: Shock, poor cardiac output, significant hemorrhage - Irregular: Atrial fibrillation, PVCs, other dysrhythmias — document and monitor
3. Respirations¶
What it measures: respiratory rate and quality.
How to measure: Count for 30 seconds × 2. Observe chest rise — do not tell the patient you are counting (they will consciously alter their rate). After counting pulse, keep fingers in place and count respirations while appearing to continue pulse check.
Note: rate, depth (adequate/shallow/deep), and effort (labored/unlabored, accessory muscle use, nasal flaring, retractions).
Normal ranges by age:
| Age Group | Normal Respiratory Rate (breaths/min) |
|---|---|
| Adult (> 12 yrs) | 12–20 |
| School-age child (6–12) | 18–30 |
| Preschool (1–5) | 22–34 |
| Infant (< 1 year) | 30–60 |
Abnormal findings: - Bradypnea (< 12 adult): Opiate/CNS depression, herniation, late shock - Tachypnea (> 20 adult): Pain, fever, anxiety, hypoxia, acidosis, compensatory respiratory drive in shock - Apnea: No breathing — BVM immediately - Agonal respirations: Slow, gasping, ineffective — treat as apnea; BVM immediately - Shallow/inadequate depth without airway obstruction: May need BVM even if rate is normal
4. Skin Signs¶
What it measures: perfusion status and autonomic nervous system response. Assessed by color, temperature, and moisture.
How to assess: Inspect skin (nail beds, mucous membranes, conjunctiva for darker skin tones), palpate skin temperature and moisture.
Normal: Warm, pink, dry
| Finding | Clinical Meaning |
|---|---|
| Pale, cool, diaphoretic | Shock, hemorrhage, sympathetic (fight-or-flight) response |
| Red (flushed), hot, dry | Hyperthermia, heat stroke, fever |
| Cyanotic (blue/gray) | Hypoxia — inadequate oxygenation or perfusion |
| Mottled | Shock, sepsis, hypothermia |
| Jaundiced (yellow) | Liver disease |
| Cool, dry | Hypothermia, vagal response |
Skin signs often change before blood pressure drops — diaphoresis and pallor with tachycardia = early shock even with normal BP.
5. Pupils¶
What it measures: neurological status, medication effects, brainstem function.
Normal: Equal, round, and reactive to light (PERRL). In normal light, 2–5 mm. Brisk constriction to light.
| Finding | Abbreviation | Clinical Meaning |
|---|---|---|
| Equal and reactive | PERRL | Normal |
| Dilated, sluggish or fixed | — | Hypoxia, herniation, death |
| Constricted (pinpoint) | — | Opiate/narcotic intoxication |
| Unequal (anisocoria) | — | Herniation (ipsilateral dilation on side of bleed), pre-existing condition, trauma |
| Non-reactive (fixed) | — | Brain herniation, death, atropine effect |
| Dilated bilaterally | — | Stimulant drugs (cocaine, amphetamine), sympathetic response, head injury |
Note: approximately 20% of people have naturally unequal pupils (benign anisocoria). Ask family or check baseline if unclear.
6. SpO2 (Pulse Oximetry)¶
What it measures: oxygen saturation of hemoglobin, expressed as a percentage.
Normal adult: ≥ 94%. For COPD patients, 88–92% is an acceptable target (hypoxic drive consideration).
See pulse-oximetry for full detail on the technique, normal values by age, and critical limitations (CO poisoning, shock, anemia, nail polish, motion artifact).
Clinical rule: Treat the patient, not the number. If SpO2 reads 97% but the patient is in obvious respiratory distress with labored breathing — treat for respiratory distress. The number can be wrong (see pulse-oximetry). Your assessment overrides any single monitor reading.
Normal Ranges Quick Reference Table¶
| Vital Sign | Infant (< 1 yr) | Preschool (1–5) | School-age (6–12) | Adult (> 12) |
|---|---|---|---|---|
| Pulse (bpm) | 100–160 | 80–120 | 70–110 | 60–100 |
| Respirations (/min) | 30–60 | 22–34 | 18–30 | 12–20 |
| Systolic BP (mmHg) | 80–100 | 80–110 | 80–120 | 90–140 |
| SpO2 | ≥ 94% | ≥ 94% | ≥ 94% | ≥ 94% |
Pediatric BP lower limit (systolic): rough rule = 70 + (2 × age in years). Below this = hypotension for age.
Trending¶
One set of vitals = a snapshot. Tells you where the patient is now.
Two sets = early trend. HR went from 88 to 104, BP from 120 to 102 — this patient is deteriorating.
Three or more sets = a direction. You can now predict where the patient is heading and escalate or de-escalate your intervention level accordingly.
Timing: - Unstable / critical patients: Repeat every 5 minutes - Stable patients: Repeat every 15 minutes - After every significant intervention: Repeat to assess effect
Critical Vitals Requiring Immediate Action¶
| Finding | Action |
|---|---|
| No respirations (apnea) | BVM immediately |
| Agonal respirations | BVM immediately |
| Respiratory rate < 8 adult (bradypnea) | Assist ventilations with BVM |
| SpO2 < 94% | Supplemental oxygen; upgrade to NRB or BVM as needed |
| SBP < 90 adult | Shock position, high-flow O2, priority transport |
| Pulse absent | CPR, AED |
| HR < 60 in a child | BVM oxygen; treat as pre-arrest |
| Fixed, dilated pupils | Herniation or death; airway and circulation priority |
NREMT Differentiators¶
Normal Vital Signs by Age — High-Yield Table¶
| Age Group | Pulse (bpm) | Respirations (/min) | Systolic BP (mmHg) |
|---|---|---|---|
| Infant (<1 yr) | 100–160 | 30–60 | 80–100 |
| Toddler (1–3) | 80–130 | 24–40 | 80–110 |
| Preschool (3–5) | 80–120 | 22–34 | 80–110 |
| School-age (6–12) | 70–110 | 18–30 | 80–120 |
| Adult (>12) | 60–100 | 12–20 | 90–140 |
Pediatric BP shortcut: Minimum acceptable systolic = 70 + (2 × age in years)
KEY DIFFERENTIATOR — Bradycardia in Children: In adults, HR 50 is concerning but often tolerated. In children, bradycardia is a pre-arrest rhythm — treat immediately with airway/O2. Children compensate until they crash; bradycardia means they are losing the fight.
KEY DIFFERENTIATOR — Hypotension is a LATE sign of shock: A pediatric or adult patient can lose up to 30% of blood volume while maintaining near-normal BP (compensated shock). Tachycardia + pale/cool/diaphoretic skin = shock even with normal BP. BP drops last — when it drops, the patient is decompensating.
Shock Vital Sign Progression¶
| Stage | BP | HR | Skin | LOC |
|---|---|---|---|---|
| Compensated (early) | Normal | ↑ (tachycardic) | Pale, cool, diaphoretic | Alert or anxious |
| Decompensated (late) | ↓ (hypotensive) | ↑↑ or slowing | Mottled, cyanotic | Confused, obtunded |
| Irreversible | Absent or barely palpable | Absent or agonal | Cold, ashen | Unresponsive |
NREMT RULE: Don't wait for hypotension to call shock. Tachycardia + poor skin signs = treat for shock now, regardless of BP.
Respiratory Rate Extremes — Action Required¶
| Rate | Meaning | Action |
|---|---|---|
| <8 /min (adult) | Hypoventilation — CO2 retention | BVM assist ventilations |
| 8–11 /min | Borderline — watch closely | O2 + consider BVM |
| 12–20 /min | Normal adult | O2 if SpO2 <94% |
| >30 /min | Severe distress or compensation | High-flow O2, ALS intercept |
| Agonal | Pre-arrest — gasping | BVM immediately |
| Absent | Arrest | BVM + CPR |
Related¶
- pulse-oximetry — SpO2 technique, limitations, and clinical decision rules
- avpu — level of consciousness correlates with vital sign abnormalities
- glasgow-coma-scale — neurological trending using scored motor, verbal, eye components
- reassessment — vital sign trending frequency (5-min critical, 15-min stable)