Fundamentals of Nursing · Vital Signs

How to Perform Vital Signs

7 min read

On this page 9 sections

In 30 seconds
Why this matters
The college version
Eli explains
Worked example
Key takeaway
Check yourself
Study tools
Sources & references

In 30 seconds

Measuring vital signs looks simple, but it is a skill with technique — and technique determines accuracy. A wrong-size cuff, a wrong route, a 15-second pulse multiplied, respirations counted while the patient knows they are watched: each produces a number that looks real but is wrong, and wrong numbers drive wrong decisions. This topic covers how each vital sign is measured and documented.

This guide is an educational overview of widely taught techniques — not a substitute for faculty-supervised practice in your skills lab. Procedures, equipment, and delegation vary by institution and scope of practice; always follow your program's and facility's protocols.

Why this matters

Every downstream decision — escalating care, calling the provider, adjusting the plan — begins with a number you produced; if technique made it wrong, the decision is wrong too. Consistency matters too: comparing today's reading to yesterday's only works if both were taken the same way. Measurement is also an infection-control moment (, clean equipment) and a relationship moment (explaining, privacy). Technique errors are classic exam traps: the best answer protects accuracy or safety.

The college version

Core Concepts

Prepare the person and the environment

Before any measurement: identify the patient with two identifiers per facility policy, explain what you are doing, and obtain permission. Provide privacy, comfort, and a quiet environment. Facility protocols may specify rest before measuring and avoiding recent food, drink, caffeine, smoking, or vigorous activity. Gather clean, working equipment — hand hygiene before and after, and between patients, is non-negotiable.

Temperature: pick the route, use it correctly

Routes include oral (under the tongue, mouth closed), tympanic (in the ear canal), axillary (in the armpit, generally lower), rectal (the most invasive — used only per facility policy; some conditions rule out certain routes), and temporal (scanned across the forehead). Each route has its own expected range and pitfalls: hot or cold drinks before oral, ear wax for tympanic, sweat for temporal. The number means nothing without the route — document it.

Pulse: count, and count long enough

The most common site is the at the wrist, palpated with the pads of the fingers. Count for 30 seconds and multiply by two when the rhythm is regular; count a full 60 seconds when irregular or unusual — a common policy and exam point. Note rhythm and strength (bounding, strong, weak, thready). For infants and when the radial pulse is hard to assess, use the , auscultated over the heart.

Respirations: count without being counted

Position yourself to see the chest rise and fall and count respirations — often right after the pulse, fingers still on the wrist so the patient does not realize you are counting breaths. Count for 30–60 seconds per facility protocol, observing rate, depth (shallow or deep), rhythm, and effort (labored breathing, noise, accessory muscles).

Blood pressure: size, position, and Korotkoff sounds

Blood pressure is usually measured by with a stethoscope and cuff (). The critical first step is cuff size: the bladder must fit the arm circumference — too small reads falsely high, too large falsely low. Position the patient with the arm supported near heart level; the patient should not talk. Locate the brachial artery at the inner elbow, place the stethoscope over it, inflate above the expected pressure, and deflate slowly. appear during deflation: the first tap (Phase 1) marks systolic; the point where sounds disappear (Phase 5, commonly used in adults) marks diastolic. Document the reading with arm and position, and follow facility protocol for verifying unusual values.

Pulse oximetry: the oxygenation estimate

A passes light through a well-perfused site (commonly a fingertip) to estimate oxygen saturation (SpO₂). Choose a warm, well-perfused site, follow the device's placement instructions, and let the reading stabilize. Readings can be unreliable with motion, poor perfusion, cold fingers, or certain conditions and nail coverings — follow device instructions and facility policy.

Document and communicate

Record each value with specifics: temperature route, pulse site, blood pressure arm and position, whether the pulse was counted a full minute, and factors that could affect the readings. Compare with the baseline and report changes per facility policy — a structured handoff (such as SBAR) is the standard.

Common Confusions

Do Not Confuse	With	Difference
Radial pulse	Apical pulse	Radial is palpated at the wrist; apical is auscultated over the heart — used for infants and when the radial is weak or irregular
Palpated blood pressure	Auscultated blood pressure	Palpation gives only a systolic estimate (when the pulse is felt again during deflation); auscultation gives systolic and diastolic via Korotkoff sounds
Cuff too small	Cuff too large	Too small → falsely high reading; too large → falsely low reading
Oral temperature	Axillary temperature	Different routes measure different sites with different expected values — always document the route
Counting 15 seconds × 4	Counting a full minute	Short counts multiply small errors, and irregular rhythms need a full 60-second count
Korotkoff Phase 1	Korotkoff Phase 5	Phase 1 (first tap) = systolic; Phase 5 (disappearance) = diastolic, commonly in adults
Measuring	Interpreting	Measuring is the technique that produces the number; interpreting compares it to baseline and context — the nurse must do both

Eli explains

The same idea, in plain words

Explain it like I’m 10

Taking vital signs is like baking from a recipe: you use the right-size measuring cup (the cuff must fit the arm), follow the steps in order, and read the numbers at the right moment. Use the wrong cup or skip a step, and the cake — or the reading — comes out wrong.

Worked example

The nurse prepares to measure Ms. Park's blood pressure:

Prepare: Two identifiers confirmed, the procedure explained, Ms. Park seated with her back supported, feet flat, arm on the table near heart level, resting quietly per facility protocol.
Size the cuff: The nurse measures her arm circumference and chooses the correct cuff — the bladder covers the right proportion of the arm, preventing a falsely high or low reading.
Position the stethoscope: The nurse palpates the brachial artery at the inner elbow and places the stethoscope bell over it.
Inflate and deflate: The cuff is inflated above the expected systolic pressure, then deflated slowly. The nurse notes the first tapping sound (systolic) and the point where sounds disappear (diastolic).
Document: The reading is recorded with arm and position, compared with baseline, and — if outside the expected pattern — rechecked and reported per facility policy.

Common errors: cuff over a thick sleeve, talking, the arm hanging below heart level, or deflating the cuff too fast.

Key takeaways

Identify the patient and explain before measuring.
Cuff size is the classic error: too small → falsely high; too large → falsely low.
Document the route and site — oral and axillary temperatures are not interchangeable, and neither are readings from different arms.
Count a full 60 seconds for irregular or unusual pulses.
Count respirations unobtrusively — patients alter their breathing when watched.
Hand hygiene and clean equipment before and after.
Korotkoff Phase 1 = systolic; Phase 5 (disappearance) = diastolic, commonly.
Follow facility policy and faculty instruction — procedures and delegation vary by setting and scope of practice.

Check yourself

6 review questions from the chapter. Try each one, then open the answer.

Why is cuff size critical in blood pressure measurement?
Show answer
Because a too-small cuff produces falsely high readings and a too-large cuff falsely low readings — the error silently corrupts the data every decision depends on.
When would a nurse use an apical pulse instead of a radial pulse?
Show answer
For infants and small children, and when the radial pulse is difficult to feel or the rhythm is irregular — the apical pulse is auscultated over the heart.
Why are respirations counted without telling the patient?
Show answer
Because patients often change their breathing when observed; counting unobtrusively produces a more accurate rate.
What are Korotkoff sounds, and what do Phase 1 and Phase 5 indicate?
Show answer
Korotkoff sounds are the tapping sounds heard through the stethoscope as the cuff deflates — Phase 1 (first tap) marks systolic pressure, and Phase 5 (disappearance of sounds) marks diastolic pressure, commonly in adults.
Why must the nurse document which route or site was used for a measurement?
Show answer
Because different routes and sites have different expected values and are not interchangeable — an oral temperature cannot be compared to an axillary one, and readings from different arms or positions cannot be compared directly.
Name three factors that can make a vital-sign reading inaccurate.
Show answer
Any of: wrong-size cuff, talking during the reading, recent food/drink/exercise/caffeine, counting a pulse too briefly, counting respirations while the patient knows they are watched, poor pulse-oximeter site or motion, or hot/cold drinks before an oral temperature.

Keep learning

Ready to build on this? Continue to the next lesson.

Study toolsKey vocabulary

Key vocabulary

Palpation: Using the sense of touch to examine — e.g., feeling the pulse with the fingers
Auscultation: Listening to internal body sounds, usually with a stethoscope
Korotkoff sounds: The sounds heard through a stethoscope as a blood pressure cuff deflates
Radial pulse: The pulse palpated at the wrist
Apical pulse: The heartbeat auscultated directly over the heart
Sphygmomanometer: The blood pressure cuff and gauge
Pulse oximeter: A device that estimates oxygen saturation (SpO₂) by passing light through tissue
Hand hygiene: Cleaning hands before and after patient contact

Sources & references

openstax.org — Fundamentals Nursing

This lesson was adapted from the open educational references above; their licenses and attributions are preserved. See Copyright & Licensing.

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