7.1 Vital Signs Overview

What Vital Signs Are and Why They Matter

Vital signs are objective measurements that reflect how the body's essential systems are working. They are called "vital" because a meaningful change can be the first warning of infection, heart failure, bleeding, or respiratory failure, often before the patient looks sick. The four primary vital signs are memorized together as TPR (Temperature, Pulse, Respirations) plus Blood Pressure (BP).

The Four Primary Vital Signs

Two measurements are often added: pain (the "fifth vital sign") and oxygen saturation (SpO2), measured by pulse oximetry, with a normal value of 95-100%.

When CNAs Measure Vital Signs

Routine timing is set by the care plan, but you also re-check vitals any time the patient changes. Routine triggers: on admission, at the start of a shift, before and after a procedure, and before certain medications when the nurse asks. Extra checks: after a fall, when consciousness changes, when the patient says they feel unwell, before and after activity or transfers, and any time the nurse directs.

Baseline, Accuracy, and the CNA Scope

A baseline is the patient's own normal value when stable and healthy. Many patients live outside textbook ranges yet are fine: a conditioned athlete may rest at a pulse of 50, and a stable 90-year-old may run a blood pressure of 145/85. Compare every reading first to the patient's baseline, then to recent prior readings, then to standard ranges.

Factors That Shift Vital Signs

Because activity inflates readings, let the patient rest 5 minutes before measuring, seated and calm.

Accuracy Is Scored on the Skills Exam

The NNAAP (National Nurse Aide Assessment Program), administered in most states by Credentia/Pearson VUE, tests vital signs hands-on. Your documented number must fall within the evaluator's tolerance: about +/- 4 beats/min for pulse and +/- 8 mmHg for blood pressure (systolic and diastolic). Miss the band and the skill is failed even if your technique looked correct, so never round or guess, count the full required time, and record immediately rather than from memory.

Report Abnormals Immediately

Trap: A CNA records and reports but never interprets. Saying "the patient has a fever from a urinary infection" or holding a medication is outside scope; report the number and the patient's complaints, and let the nurse decide.

Putting Vitals Together on the Job and on the Test

On the NNAAP skills exam you are given five randomly selected skills, and at least one is almost always a vital sign or a measurement. The single most common reason candidates fail a vitals skill is not technique but the recorded number falling outside the tolerance band, so build habits now that protect accuracy. Wash and glove appropriately, gather working equipment, count the full required time, and write the number on your worksheet the moment you read it rather than carrying it in your head while you finish the rest of the steps.

A Worked Example

A resident returns from a walk and sits down. The CNA who measures immediately gets pulse 104, respirations 24, BP 148/88. Are these abnormal? Possibly not. Activity raises all four vital signs, so the correct move is to seat the resident, wait the standard 5 minutes, and re-measure. After rest the values read pulse 82, respirations 16, BP 126/80, all within normal limits. Reporting the first set as an emergency would have been a false alarm caused by skipping the rest period.

Order of Measurement

Many programs teach a deliberate sequence so one reading does not contaminate the next:

1. Temperature first (an oral route also tells you whether the mouth is clear for talking).
2. Pulse next, counting at the radial site.
3. Respirations immediately after, with your fingers still on the wrist so the count stays natural.
4. Blood pressure last, since the cuff is the most disruptive step.

Documentation and Communication

Document with the route or site and any quality note, not just a bare figure: "T 99.2 F oral," "P 88 radial, regular," "R 18, unlabored," "BP 132/82 right arm, sitting." When you report an abnormal value to the nurse, use a clear pattern: state who the patient is, the abnormal number, the patient's baseline, and any symptom you observed. For example, "Mr. Lee's pulse is 118, his baseline is in the 70s, and he says his heart is racing." That gives the nurse exactly what is needed to act, and it keeps you firmly inside the CNA scope of observe, measure, record, and report rather than interpret or treat.