4.1 Vital Signs, Intake/Output, and Observation
Key Takeaways
- Missouri CNA basic nursing care tests data collection as a bedside safety skill: measure accurately, record promptly, and report changes without diagnosing.
- For Missouri skill testing, pulse must be within 4 beats, respirations within 2 breaths, and manual blood pressure within 6 mmHg of the RN Test Observer readings.
- Intake and output errors are usually technique errors: read graduates at eye level, measure in the assigned unit, and include only what the care plan or skill scenario requires.
- A CNA reports objective changes such as new shortness of breath, chest pain, confusion, poor intake, dark urine, dizziness, swelling, or skin changes to the nurse promptly.
Why This Section Matters in Missouri
Missouri's current nurse aide knowledge test is a 75-question exam built from state-approved subject areas. For this chapter, the important pieces are Basic Nursing Skills, Data Collection, Personal Care, Safety, and Aging Process and Restorative Care. The candidate handbook lists Basic Nursing Skills and Personal Care at eight questions each and Data Collection at four questions. That means measuring, observing, recording, and reporting are not side details; they are a large part of how Missouri checks whether a new CNA can work safely.
The Missouri CNA role is not to diagnose. The job is to observe what is happening, collect assigned data, compare it with the resident's usual condition when you know it, record what you measured, and report changes through the chain of command. On the written exam, the safest answer is often the one that stays within CNA scope: recheck if reasonable, protect the resident, report to the nurse, and document according to facility procedure.
Vital Signs as Data Collection
Vital signs are objective measurements that help the nurse judge a resident's condition. Common CNA measurements include temperature, pulse, respirations, blood pressure, pain reporting, oxygen saturation when assigned, weight, and intake/output. A CNA may collect these measurements, but the nurse interprets them and decides what they mean clinically.
| Measurement | CNA focus | Common Missouri exam trap |
|---|---|---|
| Temperature | Use the assigned route and device; report fever or unusual low temperature. | Retaking after hot or cold drinks too soon and treating the number as reliable. |
| Pulse | Use fingertips, assess rate and rhythm, count longer if irregular. | Using the thumb or reporting only a number when the rhythm is irregular. |
| Respirations | Count quietly while watching chest rise and fall. | Telling the resident you are counting breathing and changing the pattern. |
| Blood pressure | Use correct cuff placement and arm support. | Incorrect cuff size or arm position causing a misleading reading. |
| Weight | Use same scale, similar clothing, and same time when possible. | Ignoring sudden gain or loss because the resident looks unchanged. |
| Intake/output | Measure fluids in the required unit and record promptly. | Estimating from memory at the end of the shift. |
Missouri's skills checklist makes accuracy concrete. For pulse and respirations, the candidate may count for 60 seconds or count 30 seconds and multiply by two if allowed by the scenario, but must tell the RN Test Observer when the count starts and stops. The recorded pulse must be within 4 beats of the observer's rate, and the recorded respiratory rate must be within 2 breaths. For manual blood pressure, both systolic and diastolic readings must be within 6 mmHg. Those tolerances are a study signal: practice the mechanics until they are automatic.
Intake, Output, and Observation
Intake and output, often called I&O, tracks fluids going in and fluids leaving the body. Intake can include water, juice, milk, soup, ice chips after conversion, supplements, or tube feeding if the care plan tells the CNA to count them. Output can include urine, emesis, drainage, or stool measurements when assigned. Do not invent categories; follow the care plan and facility form.
For urine measurement, technique matters. Place the graduate on a flat surface, read it at eye level, and record immediately. If a urinary drainage bag is involved, keep the drainage pathway clean and avoid contaminating the drain or graduate. Missouri's urine-output skill gives a 25 mL tolerance from the RN Test Observer's premeasured output, so casual guessing is unsafe for both the exam and the resident.
Observation is broader than measurement. A resident who normally eats most breakfast but now takes two bites, sleeps through care, has dry lips, and produces dark urine may be showing dehydration, infection, medication effects, or something else. The CNA does not name the condition. The CNA reports the observations: poor intake, change in alertness, dry mouth, dark urine, and amount of output.
Scenario Traps and Reporting Language
Scenario trap: Mr. Cole's blood pressure is much lower than yesterday and he says he feels dizzy when sitting up. A poor answer is to walk him to the dining room because breakfast is starting. A better CNA response is to keep him safe, ask him to remain seated or lying as appropriate, call the nurse, and report the measured blood pressure, dizziness, position, skin color, and any other observed signs.
Another trap is charting a conclusion instead of a fact. Write and report, "Resident ate 25% of meal, drank 120 mL, and coughed twice after thin liquids," not "Resident is aspirating." Say, "New reddened area on right heel," not "pressure ulcer," unless the nurse has identified it that way. Objective language protects the resident and keeps the CNA within scope.
Quick Measurement Rules
- Prepare the resident: knock, identify yourself, explain, provide privacy, and position correctly.
- Measure with the right equipment and route.
- Repeat or recheck only when it is safe and reasonable; do not delay urgent reporting.
- Record in the assigned place, in the assigned unit.
- Report changes promptly, especially breathing trouble, chest pain, fall, fainting, new confusion, severe pain, bleeding, abnormal vital signs, or significant intake/output changes.
Basic nursing care is not only hands-on help. It is the daily noticing system of the facility. Missouri expects a CNA to be accurate enough to trust and humble enough to report rather than interpret.
A Missouri CNA candidate is assigned to count and record a resident's pulse and respirations during the skills test. Which approach best matches safe measurement practice?
While measuring urinary output from a drainage bag, which action best protects accuracy and infection control?
A resident who is usually alert becomes pale, short of breath, and newly confused while you are taking vital signs. What is the CNA's best first response?