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May.27.2021

Blood Pressure (Systolic): Palpation (Ambulatory) - CE

ALERT

If unable to palpate an artery because of a weakened pulse, use an ultrasonic stethoscope (Figure 1)Figure 1.

OVERVIEW

Blood pressure (BP) is the force exerted by blood against the vessel walls. During a normal cardiac cycle, BP reaches a peak, followed by a trough. The peak pressure occurs when the heart’s ventricular contraction, or systole, forces blood under high pressure into the aorta. When the ventricles relax, the blood remaining in the arteries exerts a trough, or diastolic, pressure against the arterial wall. Diastolic pressure is the minimum pressure exerted against the arterial wall.

Patients at risk for alterations in BP measurement include those who have:

  • Circulatory shock (hypovolemic, septic, cardiogenic, or neurogenic)
  • Acute or chronic pain
  • Rapid IV infusion of fluids or blood products
  • Increased intracranial pressure
  • Postoperative status
  • Preeclampsia of pregnancy

The standard unit for measuring BP is millimeters of mercury (mm Hg). The measurement indicates the height to which BP can sustain the column of mercury.

The most common methods for measuring BP are auscultation, using a sphygmomanometer and a stethoscope, and measurement using an electronic BP monitor. Palpation may be used to obtain an estimate of systolic BP before using the auscultation method.

During auscultation, as the sphygmomanometer cuff is deflated, five different sounds, called Korotkoff sounds, are heard over the artery. Each sound has a distinct characteristic (Figure 2)Figure 2. BP is recorded with the systolic reading (first Korotkoff sound) before the diastolic reading (beginning of the fifth Korotkoff sound). The difference between systolic pressure and diastolic pressure is the pulse pressure. For a BP of 120/80 mm Hg, the pulse pressure is 40 mm Hg, the difference between 120 mm Hg and 80 mm Hg.

Cuff size should be proportionate to the arm’s circumference. Most adults require a large adult cuff. An improper-size cuff can produce an inaccurate BP measurement. Studies show that using a cuff that is too narrow results in an overestimation of BP, whereas using a cuff that is too wide results in an underestimation of BP.undefined#ref1">1

When measuring BP in the upper arm is not possible—for example, when the available BP cuffs do not fit the upper arm properly—BP may be measured in the forearm. To obtain the most accurate reading, the proper size BP cuff for the forearm should be used; it typically has a smaller circumference than the upper arm. BP measurements in the forearm and upper arm are not interchangeable. Systolic blood pressure readings tend to be higher in more distal arteries, such as those in the forearm, whereas diastolic blood pressure readings tend to be lower in the more distal arteries.6,7 The thigh or calf can be used if measurement of the upper arms and forearms is not possible.1 Palpation of BP in the patient’s leg has limited reliability.

EDUCATION

  • Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
  • Explain the equipment and the procedure to the patient.
  • Instruct the patient about ambulatory BP threshold guidelines. In adults, normal BP is less than 120/80 mm Hg3,4 (Table 1)Table 1.
  • Educate the patient about the risk factors for hypertension.
    • Family history of hypertension, premature heart disease, lipidemia, or renal disease
    • Obesity
    • Cigarette smoking
    • Heavy alcohol consumption
    • High blood cholesterol and triglyceride levels
    • Prolonged stress from psychosocial and environmental factors
    • Sedentary lifestyle
  • Educate the patient regarding the primary strategies for preventing hypertension.2
    • Managing weight
    • Limiting sodium and saturated fat in the diet
    • Taking medications as prescribed
    • Maintaining adequate intake of dietary potassium and calcium
    • Engaging in daily exercise
    • Limiting alcohol intake
    • Avoiding tobacco products
  • Teach the patient the signs and symptoms of high BP (e.g., shortness of breath, severe headache, severe anxiety, pulsations in neck or head) and provide instructions on when to seek additional care.
  • Instruct the patient to get adequate rest before BP measurements. Tell the patient the measurements will be performed the same time each day using the same arm with the patient in the same position, either sitting or lying down.
  • Explain that the patient must remain still and quiet during the procedure.
  • Encourage questions and answer them as they arise.

PROCEDURE

  1. Perform hand hygiene. Don appropriate personal protective equipment (PPE) based on the patient’s need for isolation precautions or risk of exposure to bodily fluids.
  2. Introduce yourself to the patient.
  3. Verify the correct patient using two identifiers.
  4. Explain the procedure and ensure that the patient agrees to treatment.
  5. Ensure that evaluation findings are communicated to the clinical team leader per the organization’s practice.
  6. Review the patient’s medical record for a history of cardiovascular disease, renal disease, diabetes, and other factors that may influence BP (e.g., weight, smoking, medications).
  7. Evaluate the patient for signs and symptoms of BP alterations.
    1. Determine if the patient is at risk for high BP if the patient is experiencing these signs and symptoms:
      1. Headache (usually occipital)
      2. Facial flushing
      3. Nosebleed
      4. Fatigue
    2. Determine if the patient is at risk for low BP if the patient is experiencing these signs and symptoms.
      1. Dizziness
      2. Mental confusion
      3. Restlessness
      4. Pale, dusky, or cyanotic skin and mucous membranes
      5. Cool, mottled skin over the extremities
  8. Determine the best site for BP measurement. Avoid applying the cuff to the patient’s arm when:
    1. IV fluids are infusing.
    2. An arteriovenous shunt or fistula is present.
    3. An ipsilateral breast or axillary surgery has been performed.
    4. The arm has been traumatized.
    5. The arm has known infections or medical conditions (e.g., those causing vasoconstriction or a tumor pressing on the vascular supply).
    6. The arm has a cast or bulky bandage.
  9. If available, review the previous baseline BP and site from the patient’s record.
  10. Ensure that the patient has not exercised, ingested caffeine, or smoked immediately before BP measurement.3 Ensure that the patient does not have to void.
  11. Rationale: The urge to void can significantly increase BP. 5
  12. Ensure that the room is warm.
  13. Rationale: Exposure to cold can significantly increase systolic BP. 5
  14. Measure the patient’s arm circumference and select the appropriate-size cuff (Figure 3)Figure 3.
  15. Rationale: Proper cuff size is necessary for an accurate reading. The cuff must be wide and long enough to allow for the size of the arm or thigh. Narrow cuffs can cause an artificially high reading.
  16. Inform the patient that BP is going to be taken and that the cuff will squeeze the arm.
  17. Have the patient sit or lie down. Record the patient’s position when performing orthostatic vital signs.
    1. Rationale: BP is generally higher in the supine position than the sitting position. 5
    2. Position the patient’s arm, supported, at the heart level with the palm facing up (Figure 4)Figure 4.
    3. Rationale: If the patient’s arm is not supported at the heart level, a lower BP will be recorded when the arm is above heart level, and a higher BP will be recorded when the arm is below heart level. 1
    4. If sitting, ensure that the patient’s back is supported5 and instruct the patient to keep the feet flat on the floor with legs uncrossed.
    5. Rationale: Leg crossing can falsely increase systolic and diastolic BP.
    6. If supine, ensure the patient’s legs are not crossed.
    7. Rationale: Leg crossing can artificially increase systolic and diastolic BP.
  18. Expose the patient’s arm fully by removing constricting clothing. Do not place the BP cuff over clothing.
  19. Rationale: Placing the cuff over clothing may affect the BP measurement.
  20. Apply the BP cuff to the patient’s arm.
    1. Upper arm
      1. Palpate the brachial artery for a pulse (Figure 5)Figure 5.
      2. Position the cuff above the antecubital fossa.
      3. Apply the cuff by centering the arrows marked on the cuff over the brachial artery so that the end of the cuff is 2 to 3 cm (about 1 inch) above the antecubital fossa and allows room for placement of the stethoscope (Figure 6)Figure 6.1 If the cuff has no center arrows, estimate the center of the bladder and place it over the artery.
      4. Rationale: Positioning the cuff bladder directly over the brachial artery ensures that proper pressure is applied during inflation.
      5. Wrap the fully deflated cuff evenly and snugly around the patient’s upper arm (Figure 6)Figure 6.
      6. Rationale: A loose-fitting cuff causes false-high readings.
    2. Forearm
      1. Palpate the radial artery for a pulse.
      2. Position the cuff below the antecubital fossa.
      3. Apply the cuff by centering arrows marked on the cuff over the radial artery with the upper edge of the cuff positioned 2 to 3 cm (about 1 inch) below the antecubital fossa.1 If the cuff has no center arrows, estimate the center of the bladder and place it over the artery.
      4. Rationale: Positioning the cuff bladder directly over the radial artery ensures that proper pressure is applied during inflation.
      5. Wrap the fully deflated cuff evenly and snugly around the patient’s forearm.
      6. Rationale: A loose-fitting cuff can cause an artificially high reading.
  21. Position the manometer vertically at eye level.
  22. Rationale: Looking up or down at the scale can result in distorted, incorrect readings.
  23. Ask the patient not to speak while BP is being measured.
  24. Locate and continually palpate the brachial artery (upper arm BP) or radial artery (forearm BP) with the fingertips of one hand (Figure 5)Figure 5.
  25. Palpate the artery distal to the cuff with the fingertips of the nondominant hand while inflating the cuff rapidly to a pressure above the point at which the pulse disappears.
  26. If unable to palpate the artery because of a weakened pulse, use an ultrasonic stethoscope.
  27. Slowly release the pressure bulb valve, allowing the manometer needle to fall slowly and continuously at a rate of 2 to 3 mm Hg per second.5
  28. Observe the point on the manometer at which the pulse reappears. This point is the palpated estimate of systolic BP.
  29. Rationale: Too rapid or too slow a decline in the mercury level can cause an inaccurate measurement.
  30. Deflate the cuff fully and wait a short time.
  31. Rationale: The estimate of systolic BP determines the maximal inflation point for accurate reading by palpation. Completely deflating the cuff prevents venous congestion and an artificially high reading.
  32. Remove the cuff from the patient’s arm unless a repeat measurement is needed.
  33. Rationale: Continuous cuff inflation causes arterial occlusion, resulting in numbness and tingling of the arm.
  34. If this is the patient’s first BP evaluation, repeat the procedure on the other arm. If there is a consistent difference between the BP in the patient’s arms, use the arm with the higher pressure.
  35. Rationale: Comparison of BP in both arms helps detect cardiovascular, neurologic, and musculoskeletal abnormalities. A normal difference of up to 10 mm Hg may exist between arms. 1
  36. Assist the patient with resuming a comfortable position and return any removed clothing. Inform the patient of the BP reading, as appropriate.
  37. Clean the BP cuff per the manufacturer’s instructions and the organization’s practice. Clean the earpieces and diaphragm of the stethoscope per the organization’s practice.
  38. Return the equipment to its assigned storage space.
  39. Remove any PPE and perform hand hygiene.
  40. Document the procedure in the patient’s record.

EXPECTED OUTCOMES

  • BP is within acceptable range for patient’s age and body size.
  • Patient tolerates procedure.
  • No significant difference exists between left arm and right arm BP readings.

UNEXPECTED OUTCOMES

  • BP is above acceptable range for the patient’s age and body size.
  • BP is below acceptable range or insufficient for adequate perfusion and oxygenation of tissues for the patient’s age and body size.
  • BP reading cannot be obtained.
  • Patient experiences orthostatic hypotension.
  • A significant difference exists between left arm and right arm BP readings.

DOCUMENTATION

  • BP measurement
  • Method
  • Site used and patient’s position
  • Abnormal findings
  • BP measurement after administration of specific therapies
  • Signs and symptoms of BP alterations
  • Unexpected outcomes and related interventions
  • Education
  • Evaluation findings communicated to the clinical team leader per the organization’s practice

PEDIATRIC CONSIDERATIONS

  • The right arm is preferred for BP measurements in children for consistency and comparison with standardized BP measurement tables for age and weight.8
  • BP measurement may frighten children. A child should be prepared for the squeezing feeling of an inflated BP cuff by comparing the sensation to an elastic band on a finger or a tight hug on the arm.
  • The child’s BP should be measured before performing anxiety-producing tests or procedures.
  • A child’s or adolescent’s awareness of body size and age should be considered during the BP measurement.
    • Heavier and taller children have higher BPs than smaller children of the same age.
    • During adolescence, BP continues to vary according to body size.
  • An acceptable chart should be used for expected ranges that are based on age, height, and weight.
  • Korotkoff sounds are difficult to hear in children because of their low frequency and amplitude. Using a pediatric stethoscope is helpful.
  • Though the beginning of the fifth Korotkoff sound indicates diastolic pressure in adults, the fourth Korotkoff (distinct muffling sound) indicates diastolic pressure in children.

OLDER ADULT CONSIDERATIONS

  • Older adults, especially frail older adults, typically have lost upper arm mass, requiring special attention to BP cuff size.
  • Older adults’ skin is more fragile and susceptible to damage from cuff pressure when BP measurements are frequent. More frequent evaluations of the skin under the cuff or rotation of BP sites is recommended.
  • Older adults have increased systolic pressure because of decreased vessel elasticity.
  • In most cases, older adults experience a fall in BP after eating.
  • Older adults should be instructed to change position slowly and to wait after each change to avoid postural hypotension and prevent injuries.

REFERENCES

  1. American Association of Critical-Care Nurses (AACN). (2016). AACN practice alert: Obtaining accurate noninvasive blood pressure measurements in adults. Critical Care Nurse, 36(3), e12-e16. doi:10.4037/ccn2016590 (Level VII)
  2. American Heart Association (AHA). (2017). Changes you can make to manage high blood pressure. Retrieved April 8, 2021, from https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure
  3. American Heart Association (AHA). (2017). Monitoring your blood pressure at home. Retrieved April 8, 2021, from https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings/monitoring-your-blood-pressure-at-home#.Wuct7ExFwy9 (Level VII)
  4. American Heart Association (AHA). (2021). Understanding blood pressure readings. Retrieved April 8, 2021, from https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings#.Wucr9UxFwy9 (Level VII)
  5. Kallioinen, N. and others. (2017). Sources of inaccuracy in the measurement of adult patients’ resting blood pressure in clinical settings: A systematic review. Journal of Hypertension, 35(3), 421-441. doi:10.1097/HJH.0000000000001197 (Level I)
  6. Muntner, P. and others. (2019). Measurement of blood pressure in humans: A scientific statement from the American Heart Association. Hypertension, 73(5), e35-e66. doi:10.1161/HYP.0000000000000087 (Level VII)
  7. Pickering, T. and others. (2004). Recommendations for blood pressure measurement in humans and experimental animals. Part 1: Blood pressure measurement in humans: A statement for professionals from the subcommittee of professional and public education of the American Heart Association Council on High Blood Pressure Research. (classic reference)* Retrieved April 8, 2021 from, https://www.ahajournals.org/doi/full/10.1161/01.HYP.0000150859.47929.8e (Level VII)
  8. Schroeder, M.L. and others. (2019). Chapter 27: The child with cardiovascular dysfunction. In M.J. Hockenberry, D. Wilson, C.C. Rodgers (Eds.), Wong’s nursing care of infants and children (11th ed., pp. 958-1019). St. Louis: Elsevier.

ADDITIONAL READINGS

American Heart Association (AHA). (2017). What is high blood pressure? Retrieved April 8, 2021, from https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/what-is-high-blood-pressure (Level VII)

*In these skills, a “classic” reference is a widely cited, standard work of established excellence that significantly affects current practice and may also represent the foundational research for practice.

Elsevier Skills Levels of Evidence

  • Level I - Systematic review of all relevant randomized controlled trials
  • Level II - At least one well-designed randomized controlled trial
  • Level III - Well-designed controlled trials without randomization
  • Level IV - Well-designed case-controlled or cohort studies
  • Level V - Descriptive or qualitative studies
  • Level VI - Single descriptive or qualitative study
  • Level VII - Authority opinion or expert committee reports
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