5.1 Measuring & Recording Vital Signs

Measuring & Recording Vital Signs

Vital signs—body temperature, pulse, respirations, and blood pressure—are the foundational physiological indicators of a resident's immediate health and homeostatic status. In the state of Oregon, the Oregon Board of Nursing (OSBN) regulates the scope of practice for Certified Nursing Assistants (CNAs), stipulating that while CNAs are responsible for the accurate measurement and documentation of vital signs, they must immediately report any abnormal findings to a licensed nurse. CNAs do not independently interpret vital sign trends or make clinical decisions based on them (such as withholding medication), but their role as data collectors is critical to resident safety and early intervention.

Body Temperature

Body temperature reflects the balance between heat produced and heat lost by the body. The hypothalamus in the brain regulates this balance. As a CNA, you will measure temperature using several routes, depending on the resident's cognitive status, safety, and facility policy.

• Oral (Sublingual): The oral route is common, convenient, and reliable for cooperative, conscious adults. The normal range is 97.6°F to 99.6°F (36.5°C to 37.5°C). To measure oral temperature, the thermometer probe (covered with a disposable sheath) must be placed in the sublingual pocket at the base of the tongue, on either side of the frenulum. The resident must keep their mouth closed around the probe. If a resident has recently eaten food, chewed gum, smoked, or drank hot or cold liquids, you must wait 15 to 20 minutes before taking the temperature to avoid an inaccurate reading.
• Tympanic (Ear): The tympanic membrane shares the same blood supply as the hypothalamus, providing an accurate core temperature. The average tympanic temperature is 98.6°F (37.0°C). For an adult, gently pull the pinna of the ear up and back to straighten the ear canal before inserting the probe.
• Axillary (Underarm): The axillary route is the least accurate and is typically used only when other routes are contraindicated. The normal range is 96.6°F to 98.6°F (36.0°C to 37.0°C), which is approximately 1°F lower than the oral temperature. The probe must be placed in the center of a dry armpit, and the resident's arm must be held close to the body.
• Rectal: The rectal route is the most accurate core temperature measurement but is highly invasive. The normal range is 98.6°F to 100.6°F (37.0°C to 38.1°C), approximately 1°F higher than oral. It is contraindicated for residents with active diarrhea, rectal bleeding, recent rectal surgery, or severe cardiac conditions (due to the risk of stimulating the vagus nerve, which can dangerously slow the heart rate).
• Temporal Artery (Forehead): Measures infrared heat over the temporal artery. It is non-invasive and highly accurate when performed correctly, sliding the scanner across the forehead to the hairline.

Pulse Rate

The pulse represents the rhythmic expansion and contraction of an artery as the heart pumps blood.

• Radial Pulse: Located on the thumb side of the inner wrist. This is the most common site for checking a pulse. Under Oregon TMU skills testing standards, you must count the radial pulse for one full minute (60 seconds). You cannot count for 30 seconds and multiply by two. Your recorded value must be within 4 beats per minute of the observer's reading to pass the skill.
• Apical Pulse: Measured by listening directly to the heart using a stethoscope. It is located at the fifth intercostal space at the left midclavicular line (the apex of the heart). You must count the apical pulse for a full 60 seconds. This method is used for residents with irregular heartbeats, infants, or prior to administering certain cardiac medications (such as digoxin), as delegated by the nurse.
• Ranges and Terms: The normal adult pulse range is 60 to 100 beats per minute (bpm).
  • Tachycardia: A heart rate greater than 100 bpm. This can indicate pain, fever, dehydration, anxiety, or infection.
  • Bradycardia: A heart rate less than 60 bpm. While normal in highly conditioned athletes, it can indicate cardiac disease or medication toxicity in elderly residents.

Respiration Rate

Respiration is the act of breathing, which involves inspiration (breathing in) and expiration (breathing out). One respiration consists of one full rise and one full fall of the resident's chest.

• Normal Range: The normal adult respiratory rate is 12 to 20 breaths per minute.
• Counting Technique: Because breathing is partially under voluntary control, residents may alter their breathing patterns if they know they are being observed. To prevent this, count respirations immediately after counting the radial pulse. Keep your fingers on the resident's wrist as if you are still counting the pulse, but instead, observe the chest rise and fall.
• Oregon TMU Skills Note: You must count respirations for one full minute (60 seconds). Your recorded rate must be within 2 breaths per minute of the observer's reading.
• Terms to Know:
  • Tachypnea: Rapid breathing, greater than 20 breaths per minute.
  • Bradypnea: Slow breathing, less than 12 breaths per minute.
  • Dyspnea: Difficult or labored breathing.
  • Apnea: The absence of breathing.

Blood Pressure

Blood pressure (BP) is the force exerted by the blood against the walls of the arteries. It is recorded as a fraction: Systolic over Diastolic in millimeters of mercury (mmHg).

• Systolic Pressure: The pressure when the heart muscle contracts and pumps blood out of the chambers. It is the top number and represents the first sound heard (Korotkoff phase I) when deflating the cuff.
• Diastolic Pressure: The pressure when the heart muscle relaxes and fills with blood. It is the bottom number and represents the point where the sound disappears (Korotkoff phase V).
• Normal and Abnormal Ranges:
  • Normal: Systolic < 120 mmHg AND Diastolic < 80 mmHg.
  • Elevated: Systolic 120–129 mmHg AND Diastolic < 80 mmHg.
  • Stage 1 Hypertension: Systolic 130–139 mmHg OR Diastolic 80–89 mmHg.
  • Stage 2 Hypertension: Systolic ≥ 140 mmHg OR Diastolic ≥ 90 mmHg.
  • Hypotension: Systolic < 90 mmHg OR Diastolic < 60 mmHg. Hypotension can cause dizziness and increase fall risks.
• Manual Measurement Steps (TMU Skill Standards):
  1. Clean the earpieces and diaphragm of the stethoscope with antiseptic wipes.
  2. Position the resident's arm, fully supported, at heart level, palm up. Expose the upper arm.
  3. Palpate the brachial artery on the inner aspect of the elbow (antecubital fossa).
  4. Apply the blood pressure cuff snugly, 1 inch above the antecubital fossa, with the cuff's sensor arrow aligned over the brachial artery.
  5. Locate the radial pulse. Inflate the cuff until you can no longer feel the radial pulse (radial obliteration). Note this number and add 30 mmHg. This is your inflation target.
  6. Place the diaphragm of the stethoscope over the brachial artery.
  7. Inflate the cuff to your target pressure.
  8. Deflate the cuff slowly and steadily at 2 to 3 mmHg per second.
  9. Note the first clear tapping sound (systolic pressure) and the point where the sound completely disappears (diastolic pressure).
  10. Deflate the cuff completely and remove it. Record the measurements immediately.
  • Oregon TMU Skills Note: Your reading must be within 8 mmHg (both systolic and diastolic) of the observer's reading.