16) Measuring Blood Pressure Flashcards
How can arterial blood pressure be measured?
- Directly (invasively) by inserting catheter into artery
- Indirectly (noninvasively) using methods like oscillometry or auscultation
When is invasive blood pressure monitoring used?
- Only in critical care settings
- Due to risk of sudden blood loss from artery
What does Hypertension Canada’s 2020 Guidelines recommend?
- Validated oscillometric upper arm measurements preferred over auscultation
- AOPB preferred for in-office measurement
- Out-of-office measurements essential for white coat/masked hypertension
What percentage of Canadian family physicians still use auscultation?
- 52% still use aneroid/mercury devices with auscultation
- Not following current Canadian guidelines
What does literature say about auscultation vs automated methods?
- Auscultation is more complex, increases human error
- But automated devices have not eliminated human error completely
What is recommended for nurses?
- Electronic measurement should be encouraged
- But know proper technique for both auscultation and automated measurement
Can measuring blood pressure be delegated to unregulated care providers (UCPs)?
- In most provinces/territories, yes
- Nurse is responsible for assessing BP changes
What should the UCP be informed about when delegating BP measurement?
- Appropriate limb for measurement (typically arm, can be leg)
- Appropriate cuff size for extremity
- Frequency of measurement for patient
- Patient’s usual BP values
- Abnormalities to report to provider
What equipment is needed for BP measurement?
- Aneroid sphygmomanometer
- Appropriately sized BP cuff
- Stethoscope
- Alcohol swab
- Pen and vital sign flow sheet/documentation form
What is the first step in the procedure?
- Identify patient using at least two identifiers (e.g. name and date of birth)
- Follows employer policy and improves patient safety
Why determine the need to assess blood pressure?
- Use clinical judgment
- Certain conditions heighten risk for BP alteration
What conditions increase risk for high blood pressure?
- Cardiovascular disease, renal disease, diabetes
- Circulatory shock, acute/chronic pain
- Rapid IV fluids/blood products, increased intracranial pressure
- Postoperative conditions, toxemia of pregnancy
What are signs/symptoms of high blood pressure?
- Headache (usually occipital), flushing, nosebleed, fatigue
- Often asymptomatic until very high
What are signs/symptoms of low blood pressure?
- Dizziness, mental confusion, restlessness
- Pale, dusky, cyanotic skin/mucous membranes
- Cool, mottled skin over extremities
What sites should be avoided for BP cuff?
- IV infusion site, arteriovenous shunt/fistula
- Side of breast/axillary surgery
- Traumatized, diseased extremity or requiring cast/bulky bandage
Why determine previous baseline BP?
- Enables assessment of change in patient’s condition
- Provides comparison for future measurements
What factors can interfere with accurate blood pressure measurement?
- Acute anxiety, stress, pain
- Caffeine and tobacco use within 30 minutes
- Not resting quietly for 5 minutes beforehand
Why should exercise, smoking, and caffeine be avoided before measuring blood pressure?
- Exercise and smoking cause false elevations
- Smoking increases BP immediately, lasting up to 15 minutes
- Caffeine increases BP for up to 3 hours
What preparations are needed before measuring blood pressure?
- Explain procedure to patient
- Have patient rest at least 5 mins (sitting/lying) or 1 min (standing)
- Ask patient not to speak during measurement
Why are these preparations important?
- Allows patient to relax
- Avoids falsely elevated readings
- Enables objective comparison to rested readings
Why is selecting the appropriate cuff size crucial?
- Improper size results in inaccurate readings
- Too small/loose cuff can cause falsely high readings
- Too large cuff can cause falsely low readings
What should be checked regarding the cuff components?
- Release valve is clean and moves freely
- Inflation bulb and tubing are intact and leak-free
Why perform hand hygiene before measuring blood pressure?
- Reduces transmission of microorganisms between patient and nurse
What factors ensure patient comfort during measurement?
- Warm, quiet, relaxing environment
- Patient in sitting or lying position
- Reduces stress affecting the reading
What is the proper patient positioning for blood pressure measurement?
- Sitting or lying position
- Forearm at heart level, thigh flat (provide support)
- For arm: palm up
- For thigh: knee slightly flexed
- If sitting: legs uncrossed, feet on floor
Why is proper positioning important?
- Unsupported extremity can cause isometric exercise, increasing diastolic BP
- Crossed legs can falsely elevate BP readings
What should be done before applying the cuff?
- Expose the extremity by removing constricting clothing
- Ensures proper cuff application
How should the cuff be positioned?
- Palpate brachial (arm) or popliteal (leg) artery
- Center deflated cuff bladder over artery
- Position cuff 2.5cm above pulsation site
- Wrap cuff evenly and snugly around extremity
Why is cuff positioning over artery important?
- Ensures proper pressure is applied during inflation
- Loose cuff causes falsely high readings
What should be avoided when applying the cuff?
- Do not place cuff over clothing
How should the manometer gauge be positioned?
- Position gauge no further than 1 meter away
- Ensures gauge indicates correct readings
What is the purpose of the two-step method?
- Provides estimate of systolic pressure
- Assists in determining level of cuff inflation
- Useful when baseline BP is unknown
What are the steps for the first part of the two-step method?
- Relocate and palpate brachial/popliteal pulse
- Inflate cuff rapidly to 30mmHg above pulse disappearance
- Slowly deflate, note reading when pulse reappears
- Fully deflate cuff, wait 1 minute
Why are these steps important for the 2 step method?
- Relocating prevents false low readings
- Palpation determines maximal inflation point
- Deflating fully prevents venous congestion and false high readings
What should be done with the stethoscope?
- Place earpieces in ears, ensure clear sounds
- Earpieces should follow ear canal angle
- Relocate pulse, place bell/diaphragm over it
- Do not let bell touch cuff or clothing
Why is proper stethoscope placement crucial?
- Ensures optimal sound reception
- Improper placement causes muffled sounds
- Can result in false low systolic, false high diastolic readings
What should be done with the pressure bulb valve?
- Close valve clockwise until tight
- Prevents air leak during inflation
How should the cuff be inflated?
- Rapidly inflate to 30mmHg above previously palpated systolic pressure
- Uses patient’s estimated systolic pressure
How should the cuff be deflated during the two-step method?
- Slowly release pressure bulb valve
- Allow needle to fall at 2-3 mmHg/second
- Ensure no extraneous sounds are audible
Why is the rate of deflation and noise level important?
- Too rapid or slow deflation causes inaccurate readings
- Noise interferes with precise Korotkoff sound determination
What indicates the systolic pressure reading?
- Note point when first clear Korotkoff sound is heard
- The sound will gradually increase in intensity
How is diastolic pressure determined in children?
- Continue deflating cuff
- Note point when sound becomes muffled/dampened
- The fourth Korotkoff sound indicates diastolic in children
How is diastolic pressure determined in adults?
- Continue gradual deflation
- Note point when sound disappears
- Listen 10-20 mmHg after last sound, then quickly release remaining air
- Beginning of fifth Korotkoff sound indicates diastolic in adults
When is the one-step method used?
- For frequent measurements
- When previous systolic inflation level is known
What are the initial steps for the one-step method?
- Place stethoscope in ears, ensure clear sounds
- Relocate brachial/popliteal artery
- Place bell/diaphragm over artery, avoid touching cuff/clothing
- Close bulb valve tightly
How should the cuff be inflated in the one-step method?
- Quickly inflate to 30 mmHg above palpated systolic pressure
- Prevents air leak and ensures accurate systolic measurement
How is diastolic pressure determined in children using the one-step method?
- Continue deflating cuff
- Note point when sound becomes muffled/dampened
- The fourth Korotkoff sound indicates diastolic in children
How is diastolic pressure determined in adults using the one-step method?
- Continue gradual deflation
- Note point when sound disappears
- Listen 10-20 mmHg after last sound, then quickly release remaining air
- Beginning of fifth Korotkoff sound indicates diastolic in adults
What does Hypertension Canada recommend for auscultation?
- Take at least 3 measurements in same arm/position
- Discard first reading
- Average the latter two readings
Why take multiple readings?
- Increases accuracy of blood pressure measurement
When should you repeat on the other arm?
- If assessing patient’s BP for the first time
- Compares readings between extremities to detect circulation problems
What is considered a normal difference between arm readings?
- Difference of 5-10 mmHg between extremities is normal
What should be done after measurement?
- Assist patient to comfortable position
- Cover arm if previously clothed
- Promotes comfort and well-being
How should the cuff be handled?
- Wipe with disinfectant or dispose according to policy
- Reduces transmission of microorganisms between patients
Why discuss findings with the patient?
- Promotes patient participation in care
- Increases understanding of health status
Why perform hand hygiene?
- Reduces transmission of microorganisms between patient and nurse
What should the reading be compared to?
- Previous baseline value
- Acceptable value for patient’s age
- Evaluates change in condition and alterations
In what situations is it necessary to compare blood pressure readings across multiple extremities?
- Critically ill patients
- Patients with peripheral vascular disease
If using upper extremities, which arm should be used for subsequent assessments?
- Use the arm with the higher blood pressure reading
- Unless contraindicated
Why correlate blood pressure with pulse assessment and cardiovascular signs/symptoms?
- Blood pressure and heart rate are interrelated
What should be done if unable to obtain a blood pressure reading?
- Measure pulse and respiratory rate to check for crisis
- Assess for decreased cardiac output signs (weak pulse, confusion, pallor, cyanosis)
- Notify nurse/provider immediately if signs present
- Use alternative sites (lower extremity) or methods (Doppler, palpation)
- Repeat with sphygmomanometer, as electronic devices less accurate with low blood flow
What interventions are needed if blood pressure is insufficient for tissue perfusion?
- Compare to baseline value (systolic 90 mmHg may be acceptable)
- Position patient supine to enhance circulation
- Restrict activity if causing BP decrease
- Assess for decreased cardiac output signs and notify if present
- Increase IV rate or give vasoconstrictor medications if ordered
What should be done if blood pressure is elevated above acceptable range?
- Repeat measurement on other arm and compare
- Verify correct cuff size and placement
- Ask colleague to repeat in 2 minutes
- Observe for symptoms like headache, confusion (may be asymptomatic)
- Report elevated BP to nurse/provider immediately
- Administer antihypertensive medications as ordered
What should be done after obtaining a blood pressure reading?
- Inform patient of the value
- Explain need for periodic reassessment
Where should blood pressure readings be documented?
- Record in nurses’ notes or vital sign flowsheet
- Document in narrative notes after specific therapies
What should be reported regarding blood pressure readings?
- Report any abnormal findings to the nurse in charge or provider
What should be considered for home blood pressure monitoring?
- Assess home noise level to find quietest room
- Consider electronic cuff if patient has hearing difficulties, resources, and dexterity
Why can’t blood pressure be taken on the arm after a mastectomy?
- Lymph node removal can cause lymph fluid buildup in the arm (lymphedema)
- Blood pressure cuff pressure on the arm could worsen or trigger lymphedema
What are potential complications of lymphedema?
- Swelling, puffiness, heaviness
- Aching or burning sensation
- Trouble moving affected limb joint
What are the main components of a sphygmomanometer?
- Pressure manometer
- Inflatable cuff with bladder
- Pressure bulb with release valve
What is the ideal cuff bladder width?
- 40% of the arm’s circumference
Where should the cuff’s lower edge be positioned?
- 3 cm above the antecubital fossa
- To allow room for stethoscope
What should the bladder length of a blood pressure cuff cover?
- 80 to 100% of the arm’s circumference
What should the bladder width be in relation to the arm’s circumference?
Close to 40% of the arm’s circumference
What is the best environment for blood pressure measurement by auscultation?
- Quiet room
- Comfortable temperature
What is the preferred patient position for blood pressure measurement?
- Sitting position
- Lying or standing are alternatives
Why is consistent patient positioning important for routine measurements?
- Enables meaningful comparison of blood pressure values
What factors should be controlled before measuring blood pressure?
- Pain
- Anxiety
- Exertion
Why is it important to minimize perceptions of a stressful environment?
- To reduce any effect on blood pressure measurement
What should be done during the initial blood pressure assessment?
- Measure and record blood pressure in both arms
- Normally pressures differ by 5-10 mmHg between arms
What should be done in subsequent assessments?
- Measure blood pressure in the arm with higher reading
- Report differences >10 mmHg to provider (indicates vascular problems)
What should be done regarding the patient’s usual blood pressure?
- Ask patient to state their usual blood pressure
- If unknown, inform patient of reading after measurement
What patient education is important?
- Educate on optimal blood pressure values
- Educate on risk factors for hypertension
- Educate on dangers of hypertension
How does indirect blood pressure measurement work?
- Inflated cuff collapses artery, blocking blood flow
- Systolic pressure is when blood flow/sound returns on deflation
What are the Korotkoff sounds?
- Described by Nikolai Korotkoff in 1905
- Correspond to systolic onset, turbulence, and diastolic pressure
How are systolic and diastolic pressures recorded?
- Systolic - note first Korotkoff sound
- Diastolic - note 5th sound (disappearance) in adults
Why is obtaining an accurate blood pressure measurement essential?
- Blood pressure findings prompt medical decisions
- Blood pressure findings prompt nursing interventions
What should be done when unsure of a blood pressure reading?
- Ask a colleague to reassess the blood pressure
How can preparing the child help with cooperation?
- Explain the “tight hug” sensation of the cuff
Why are Korotkoff sounds difficult to hear in children?
- Low frequency and amplitude
- Pediatric stethoscope bell can help
Which Korotkoff sound represents diastolic pressure in infants/children?
- The 4th sound, which is typically muffled
When should an ultrasonic stethoscope be used?
- When unable to auscultate sounds due to weakened arterial pulse
What does an ultrasonic stethoscope enable?
- Allows hearing of low-frequency systolic sounds
For whom is an ultrasonic stethoscope commonly used?
- Infants
- Children
- Adults with low blood pressure
When is the indirect palpation technique useful?
- For patients with arterial pulsations too weak for Korotkoff sounds
- Conditions like severe blood loss or decreased heart contractility
What can be assessed by palpation? What is difficult?
- Systolic blood pressure can be assessed
- Diastolic pressure is difficult to assess by palpation
How should palpated blood pressure be recorded?
- Record systolic value and note it was palpated (e.g. “RA 90/—, palpated, supine”)
What is the auscultatory gap?
- Temporary disappearance of sounds in hypertensive patients
- Occurs between 1st and 2nd Korotkoff sounds
Why is the auscultatory gap important?
- May cause underestimating systolic or overestimating diastolic pressure
- Inflate cuff high enough to hear true systolic before gap
How can palpation help determine cuff inflation level?
- Palpate radial artery
- Inflate 30 mmHg above pressure when radial pulse disappeared
How is the auscultatory gap range determined?
- Note pressures when radial pulse disappeared and reappeared
- Record this range (e.g. “gap 180 to 160”)
What is the delegation consideration for palpating blood pressure?
The skill cannot be delegated to unregulated care providers
When might lower extremity blood pressure measurement be needed?
- Upper extremities inaccessible due to dressings, casts, IV catheters, etc.
- Comparing upper and lower pressures for certain conditions
Which artery is used for lower extremity blood pressure?
- Popliteal artery behind the knee
What type of cuff is required for lower extremity blood pressure?
- Wide and long enough for larger thigh girth
What patient position is best for measuring lower extremity blood pressure?
- Prone position
If prone is impossible, during lower extremity blood pressure what should be done?
- Ask patient to flex knee slightly for artery access
How should the cuff be positioned for lower extremity blood pressure?
- 2.5 cm above popliteal artery
- Bladder over posterior midthigh
How does lower extremity blood pressure procedure differ from brachial artery?
- Procedure is identical to brachial auscultation
How does leg systolic pressure typically compare to brachial?
- Usually 10-40 mmHg higher in legs
How does leg diastolic pressure compare to brachial?
- Should be the same as brachial
How is AOBP measurement performed?
- Multiple measurements at 1-2 minute intervals
- First by nurse to verify cuff position/validity
- Rest with patient alone in quiet room
What should be recorded for AOBP?
- Average BP displayed
- Heart rate
- Arm used
- Patient position (supine, sitting, standing)
What are advantages of AOBP over manual?
- Reduces white coat and masked hypertension risk
- Easy to use, no stethoscope knowledge needed
- Enables BP assessment during interactions
- Limits interaction to decrease error risk
What types of portable home devices are recommended?
- Electronic digital readout devices (no stethoscope needed)
- Minimize auscultation-induced errors
What can be evaluated by assessing blood pressure and pulse?
- Patient’s general cardiovascular health state
- Responses to other system imbalances
What are defining characteristics of certain nursing diagnoses related to blood pressure?
- Hypotension
- Hypertension
- Orthostatic hypotension
- Narrow or wide pulse pressures
List some nursing diagnoses related to BP/pulse abnormalities.
- Activity intolerance
- Anxiety
- Decreased cardiac output
- Deficient/excess fluid volume
- Risk for injury
- Acute pain
- Ineffective tissue perfusion
How are nursing interventions determined?
- Based on the identified nursing diagnosis
- And related factors like poor intake, heat exposure, valve disease history
How does the nurse evaluate intervention outcomes?
- By reassessing the patient’s blood pressure after each intervention
