NCLEX-RN cheat sheet · Labs and diagnostics

Vital signs and deterioration

Ranges by age, oximetry limits, orthostatics, early warning signs and escalation

AI-checkedChecked by AI against current guidelines, with spot-checks by a registered nurse.

Vital signs are quick to take and easy to get wrong. Most clients who crash in hospital warn us first, often hours before: the skill is noticing the quiet signs, and acting on them.

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At a glance

Heart rate by age (resting examples)

Age	Heart rate
Newborn	100 to 160 bpm
Infant	About 80 to 140 bpm
Toddler	80 to 130 bpm
School age	70 to 100 bpm
From adolescence	60 to 100 bpm

References differ: Resting examples; rates run lower asleep. In infants and children up to five, the apical pulse is best practice.

Breathing

Newborns and infants: 30 to 60 breaths a minute; irregular breathing is common.
Adults commonly breathe 12 to 20 times a minute, though references differ (MedlinePlus gives 12 to 18). Don't call 10 a minute normal without context.
Distress: nasal flaring, neck and chest muscles working, noisy breathing, leaning forward on the arms.
Count the breathing rate for a real minute: a rising rate is an important clue.

Measuring it right

Sign	Normal, and getting it right
Temperature	Oral about 35.8 to 37.3 C (96.4 to 99.1 F). Document the route: ear and rectal run higher than oral; armpit and forehead lower. After eating, a hot or cold drink, or smoking, follow the device and protocol (MedlinePlus advises waiting 20 to 30 minutes)
Ear and infants	Skip the ear with a suspected ear infection. Under 3, pull the outer ear down; older children and adults, up and back. In infants, rectal is the most accurate, but not always recommended: newborn protocols often use the armpit
Pulse	Count a full 60 seconds, especially if irregular: rate, rhythm, force and equality. The apical pulse (fifth space, left midclavicular line, a full minute) is the most accurate, and is used before heart medicines
Pulse oximetry	Adult target 94 to 100%. COPD with carbon dioxide retention risk: oxygen often targets 88 to 92%, pending a blood gas. It's an estimate: severe anemia can look normal; poor circulation, nail polish, movement and bright light can mislead; readings may be less accurate on darker skin
Blood pressure	Cuff width about 40% of the arm's circumference; bladder covers 80 to 100%. Rest at least 5 minutes. Avoid an arm with a dialysis fistula, clot, lymphedema, wound or IV. Palpate while inflating first, or a silent gap can make it falsely low; then deflate slowly

Pulse deficit: A weak beat may not reach the wrist, as in atrial fibrillation. Count apical and radial for a full minute, subtract, and report the difference.

Blood pressure

Range	Reading
Normal	Under 120/80 mmHg
Elevated	Systolic 120 to 129 mmHg
Stage 1	130 to 139, or 80 to 89 mmHg
Stage 2	140 or more, or 90 or more mmHg
Severe	Systolic over 180, or diastolic over 120 mmHg
Hypotension	Under 90/60 mmHg

Report: Readings out of range for age, or with symptoms, at once. Under 3: not routine at checkups; measure if at risk or ill.

Orthostatic vital signs

Orthostatic hypotension: a drop of at least 20 mmHg systolic, or at least 10 mmHg diastolic, within 3 minutes of standing.
Take the baseline lying down, then stand the client, if able, and repeat pressure and pulse at 1 and 3 minutes.
Use the same arm and equipment, and stay close: dizziness can cause a fall, and some clients drop only after 3 minutes.
Dizzy, with a drop that meets the definition: help the client sit or lie down, and report it.

Early, quiet signs of deterioration

	Early signs	What it means
Low oxygen	Anxiety, restlessness, new confusion; then the breathing and heart rate climb	The saturation falls; blue skin is a late sign. Never sedate a restless client before you've checked oxygen and breathing
Rising carbon dioxide	Sleepier, with slower, shallower breaths, while the saturation can look normal	A blood gas shows PaCO2 over 45 mmHg and acidic blood. A normal saturation isn't proof, especially with lung disease, opioids or sedation
Sepsis	Fever or chills, a fast heart rate or weak pulse, shortness of breath, confusion, clammy skin, extreme pain, low blood pressure	A medical emergency (life-threatening organ dysfunction): alert the provider at once, follow your sepsis protocol, and reassess often. Minutes matter

Same client, four checks

Time	Pulse	Breaths	BP	Mental status
0800	84	16	128/76	Alert
1000	96	20	122/74	Alert
1200	108	24	110/70	Restless
1400	118	28	98/64	Confused

Read the trend: The pulse and breathing climbed first, and the pressure fell later; the time to act was before noon. Compare every set with the baseline and the last set.

Rapid response: example triggers (AHRQ PSNet; facilities set their own)

Sign	Call when
Heart rate	Over 140 or under 40 bpm
Breathing	Over 28 or under 8 breaths a minute
Systolic BP	Over 180 or under 90 mmHg
Saturation	Under 90% despite oxygen
Before any cutoff	An acute change in mental status, low urine output, or a nurse who is worried

Call early: Any staff member can call; some hospitals let clients and families call too. Teams work best called early, not as a last resort.

Priority and safety calls

★ Restless or newly confused? Think oxygen: assess the airway and breathing, give oxygen as ordered, and escalate, before any sedative.
★ Sleepy, with slow, shallow breathing and a normal saturation: the saturation may hide rising carbon dioxide, so escalate.
If you're worried, that alone is reason enough to call rapid response.
Quiet signs count too: falling urine output, new or extreme pain, cool and clammy skin. In older adults, new confusion may be the first sign of infection.
Escalate with SBAR: situation, background, assessment, recommendation. Have results and medicines ready if you can, but don't delay an urgent call to find them.
Cold hands in shock can give a misleading low reading: assess the client, and try the earlobe or forehead.
Delegate the measuring, not the meaning: the nurse analyzes and reports the numbers.
Never press both carotid pulses at once: it can cut blood flow to the brain.

How the NCLEX tests it

Vital signs stems: orthostatic numbers, an irregular pulse, an oximeter you shouldn't trust, a toddler's ear, and the arm to avoid.
Traps: a 30-second count of an irregular pulse, trusting the oximeter over the client, coffee before an oral reading, a fistula arm.
Deterioration stems: new restlessness or confusion, a creeping breathing rate, a sleepy client with a normal saturation, a worrying trend.
Traps: one reassuring number, sedating before assessing, waiting for the next scheduled check, calling it anxiety.
Trends beat single numbers; compare with baseline.
Severe anemia with an SpO2 of 97%: the reading may look normal even though too little oxygen is being carried, so assess the client.

Practice it next

This sheet comes from Vital signs: measuring and interpreting and Recognizing deterioration across body systems in our NCLEX-RN course. Try free practice questions, or see the lessons it was written from.

Free NCLEX practice questions The NCLEX-RN course

Quick self-quiz

Count an irregular pulse for a full ___ seconds.
Show answer
60
Orthostatic hypotension: a systolic drop of at least ___ mmHg within 3 minutes of standing.
Show answer
20
For a child under 3, pull the outer ear ___ for a tympanic reading.
Show answer
down
The cuff's width is about ___% of the arm's circumference.
Show answer
40
On a blood gas, rising carbon dioxide shows as a PaCO2 over ___ mmHg.
Show answer
45
Blue skin is a ___ sign of low oxygen.
Show answer
late
SBAR: situation, background, assessment, ___.
Show answer
recommendation

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Sources

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