5.3 Baseline Vital Signs Without Delay

What a Baseline Set Includes

After the immediate life threats of airway, breathing, and circulation are managed, the EMR obtains baseline vital signs — the first measurable snapshot that every later reading is compared against. A complete baseline includes:

• Respirations — rate, rhythm, depth, effort
• Pulse — rate, strength, regularity
• Blood pressure — when equipment and time allow
• Skin — color, temperature, moisture
• Pupils — equal, round, reactive to light (PERRL)
• Pulse oximetry (SpO2) — percent oxygen saturation
• plus level of consciousness (AVPU) and pain as supporting findings

The governing rule is in the section title: without delay, but also without delaying care. You take vitals as soon as it is safe and practical, but you never withhold ventilation, bleeding control, or CPR to count a pulse rate. A single set of numbers is a photograph; the trend across repeated sets is the movie that tells you whether the patient is improving or deteriorating.

Normal Vital-Sign Ranges

These numbers are the most heavily tested facts in the chapter. Know the adult values cold, and know the direction pediatric values move (faster heart/respiratory rates, lower blood pressure).

Pediatric vital signs by age (resting):

A quick field estimate for a child's minimum acceptable systolic BP is 70 + (2 x age in years). SpO2 below 94% suggests hypoxia and prompts oxygen; below 90% is an emergency requiring aggressive oxygenation and possible ventilation.

Pulse Oximetry Pitfalls

The pulse oximeter (SpO2) is convenient but easy to misread. It can give a falsely high or unreliable reading when the patient has poor perfusion (cold, shocky fingers), is wearing nail polish, is in carbon-monoxide poisoning (the device reads CO-bound hemoglobin as if it were oxygen, so it shows a normal number on a hypoxic patient), or has heavy motion or bright ambient light. The exam point: treat the patient, not the number. A patient who looks blue and labored gets oxygen even if the oximeter reads 96%, and a low reading on a cold, perfused-poorly finger is rechecked before you trust it.

Gathering and Interpreting the Baseline

Measure respirations without telling the patient (people change their breathing when watched): count for 30 seconds and double, or a full 60 seconds if irregular. Count the pulse the same way and note its strength (bounding, normal, weak/thready). Blood pressure can be taken by auscultation (stethoscope) or palpation (feeling the radial pulse return — gives only a systolic number, charted as "110/P"). Check pupils for size, equality, and reaction; the normal finding is PERRL — pupils equal, round, and reactive to light.

Unequal pupils can suggest a head injury or stroke; pinpoint (constricted) pupils suggest opioid use or a brainstem problem; dilated, fixed pupils suggest severe hypoxia, drug effects, or brain injury; pupils that do not react to light are an ominous neurologic sign. Note skin temperature with the back of your hand and ask about or measure body temperature when relevant, especially in environmental emergencies and possible infection.

The most important interpretation rule for the exam: one normal vital sign never cancels a sick appearance or a dangerous mechanism of injury. A trauma patient ejected from a car who has a normal blood pressure is not stable — they may be compensating and about to crash. Likewise, a normal SpO2 does not rule out a serious problem if the patient looks distressed or the story is alarming. Treat the patient and the trend, not a single number.

Reassessment intervals

• Unstable patient: repeat vitals every 5 minutes.
• Stable patient: repeat every 15 minutes.
• After any major intervention (oxygen, BVM, bleeding control), recheck to confirm the patient is responding.

Common baseline errors to avoid

• Counting respirations while the patient watches — they change their pattern; observe discreetly.
• Trusting a cuff over the patient — a sick-looking patient with a normal BP is still sick.
• Skipping skin and mental status — these are fast, free, and among the earliest perfusion clues.
• Taking only one set — a lone reading cannot show a trend; repeat and compare.
• Letting vitals delay a life-saving intervention — airway, breathing, circulation, and bleeding control always come first.

Used correctly, the baseline is the anchor point: every reassessment is read against it to answer the one question that matters between scene and hospital — is this patient getting better or worse?

Worked scenario

A pale, sweaty 4-year-old has a heart rate of 150 and a "normal" systolic BP of 95. Trap: "BP is normal, so the child is fine." Using 70 + (2 x 4) = 78 as the floor, 95 is technically above it — but the tachycardia plus pale, clammy skin is early shock. Children keep their blood pressure normal until they suddenly decompensate, so the EMR treats for shock, gives oxygen, keeps the child warm, and expedites transport.