Blood Pressure, Height & Weight Measurement
Key Takeaways
- Normal adult blood pressure is approximately systolic below 120 mmHg and diastolic below 80 mmHg; report readings outside ordered parameters or symptomatic changes immediately.
- Blood pressure is measured with cuff size appropriate to arm circumference—bladder width 40% and length 80% of arm; too-small cuff falsely elevates reading.
- Height is measured standing against flat wall; weight on calibrated scale with resident in light clothing, same time of day when tracking trends.
- CNAs record measurements on flow sheets and report abnormal findings; they do not adjust antihypertensive medications.
- Blood pressure, weight, and urinary output measurement are among the NNAAP skills that satisfy Prometric one-measurement-skill requirement.
Quick Answer: Use the correct cuff size, position the resident feet flat/back supported/arm at heart level, take BP after 5 minutes rest, record both numbers, and report abnormal readings—never change medications.
Blood Pressure Basics
Blood pressure reflects force of blood against artery walls.
| Term | Meaning |
|---|---|
| Systolic | Pressure during heart contraction (top number) |
| Diastolic | Pressure during relaxation (bottom number) |
Normal adult (approx.): systolic <120 and diastolic <80 mmHg.
Cuff Size Matters
| Error | Result |
|---|---|
| Cuff too small | Falsely high reading |
| Cuff too large | Falsely low reading |
Bladder should encircle 80% of arm; width 40% of arm circumference.
BP Measurement Steps
- Resident seated, back supported, feet flat, leg uncrossed 5 minutes
- Expose upper arm; select proper cuff
- Apply cuff 1 inch above elbow; artery marker over brachial artery
- Palpate radial pulse; inflate cuff ~30 mmHg above where pulse disappears
- Place stethoscope bell over brachial artery (not under cuff)
- Inflate 20–30 mmHg above estimated systolic
- Open valve slowly (2–3 mmHg drop per second)
- Note first Korotkoff sound = systolic; disappearance = diastolic
- Deflate completely; remove cuff; record both numbers with arm used and position
Do not take BP on arm with IV, dialysis fistula, mastectomy side, or injury unless ordered.
Korotkoff Sounds (Awareness)
The first tapping sound heard as cuff deflates is systolic pressure. The point where sounds disappear is diastolic. If sounds persist to zero, note and report per facility policy—do not guess diastolic.
Hypertension and Hypotension Reporting
| Reading Category | Typical CNA Action |
|---|---|
| Systolic ≥180 or diastolic ≥100 | Report immediately |
| Systolic <90 with symptoms | Report immediately; stay with resident |
| New headache with elevated BP | Report before giving PRN on your own |
CNAs never adjust antihypertensive medications or tell residents to skip doses.
Height Measurement
Standing height against wall-mounted stadiometer:
- Shoes off; heels together, back flat to wall
- Head in Frankfurt plane (ear canal level with lower eye orbit)
- Read at top of head
For non-ambulatory residents, knee-height or arm-span formulas may be used by nursing—follow care plan.
Weight Measurement
| Principle | Application |
|---|---|
| Same scale | Consistency for trends |
| Same time of day | Reduces fluid variation |
| Light clothing | Remove shoes, heavy outerwear |
| Zero balance | Check scale before use |
| Safety | Use chair or bed scale if ambulation unsafe |
Sudden weight gain may signal fluid retention—report per policy.
Bed and Chair Scales
For residents who cannot stand, use bed scale or chair scale per facility equipment. Lock wheelchair brakes on chair scales; ensure resident safety straps used only per policy—not as restraints.
Reporting Abnormal Values
| Finding | CNA Action |
|---|---|
| BP >180/100 or <90/60 (symptomatic) | Report now |
| Dizziness with low BP | Stay with resident; report |
| 3+ lb gain in 24 hours or 5+ lb in week | Report (possible fluid issue) |
Worked Scenario
You obtain BP 198/104, resident reports headache. First action?
Report immediately to nurse; stay with resident. Do not administer antihypertensive or tell resident it is "just stress."
Prometric Skills Notes
If blood pressure is your measurement skill:
- Critical steps include proper cuff placement, stethoscope placement, accurate reading, recording on form
- Resident identification and hand hygiene frame the skill
Orthostatic Hypotension Awareness
Some residents drop BP when moving from lying to sitting. If dizziness occurs during dangling before ambulation, stop the transfer, lower resident safely, and report—do not complete stand pivot.
Exam Traps
- Legs crossed during BP (elevates reading)
- Cuff over clothing
- Talking during measurement
- Recording only systolic
- Taking BP on affected mastectomy arm by default
- Deflating cuff too quickly (inaccurate diastolic)
Vital Sign Trends and NY Reporting Thresholds
Single readings matter less than patterns. Report trends across shifts: rising BP, falling weight, sudden gain.
Orthostatic Vital Signs (Awareness)
Nurses may order lying, sitting, standing BP for dizziness. CNAs assist positioning and may obtain readings when delegated. Drop in systolic ≥20 mmHg or diastolic ≥10 mmHg on standing is significant—report.
Automated vs Manual BP
Many NY facilities use automated cuffs for routine rounds. Prometric skills test manual auscultation—practice both. Automated cuffs can be inaccurate with arrhythmias or very large arms.
Weight Scale Types
| Scale | Resident Type |
|---|---|
| Standing platform | Ambulatory |
| Chair scale | Cannot stand safely |
| Bed scale | Bedbound |
| Lift scale | Bariatric with mechanical lift |
Weigh at same time daily—before breakfast is standard for fluid balance tracking.
Height for BMI (Awareness)
Nurses calculate BMI from height and weight. Accurate height on admission matters for nutrition assessment. CNAs obtain measurements; nurses interpret.
Reporting Weight Changes to Charge Nurse
| Change | Report |
|---|---|
| +2 lb in 24 hours | Possible fluid retention |
| +5 lb in 7 days | CHF exacerbation concern |
| -5 lb in 30 days | Malnutrition workup |
Auscultation Tips for Skills Exam
In noisy test environments, palpate radial pulse while deflating to confirm systolic if Korotkoff sounds are faint. Keep stethoscope earpieces angled forward. If you cannot obtain reading, report difficulty—do not invent numbers on the skills form or in clinical practice.
Height Loss in Osteoporosis
Elderly residents lose height with spinal compression. Compare to admission height; report significant change. Kyphosis may require seated height measurement per nursing protocol.
NY Facility Parameter Sheets
Most nursing homes post vital sign parameters at the nurses station. Learn your clinical site's thresholds during training—they may be stricter than textbook normals. When in doubt on the exam, report abnormal findings to the nurse immediately rather than monitoring silently.
A blood pressure cuff that is too small for the resident arm will most likely produce:
Before measuring blood pressure, the resident should be seated with feet flat and back supported for at least:
On which arm should the nurse aide avoid routine blood pressure measurement without a specific order?
After obtaining a blood pressure reading, the nurse aide should: