Measurement of blood pressure is an important part of vital sign measurement, identification of a patient's baseline status, and identification of changes in a patient's status (Taylor et al., 2023). Normal blood pressure is defined as a systolic pressure ;120 mm Hg and 80 mm Hg (Whelton et al., 2018). Table 2-2 identifies the categories for blood pressure levels in adults.

Automated, electronic oscillometric blood pressure devices determine blood pressure by analyzing the sounds of blood flow or measuring the amplitude of the oscillations (fluctuations) in blood flow upon deflation or inflation of the cuff (Figure 1). These devices can be set to take and record blood pressure readings at preset intervals. There has been a shift away from manual auscultatory blood pressure measurement to the use of oscillometric measurement method, supported by improved device technology, as well as the recommendation to obtain multiple blood pressure readings to increase accuracy (Muntner et al., 2019). The measurement of blood pressure using the manual auscultatory method is described in Skill 2-8 on page 85. Systolic blood pressure can also be estimated by palpation or using a Doppler ultrasound device (refer to the Skill Variation in Skill 2-8 on page 93).

The nurse must know the appropriate equipment to use, including choosing the appropriate blood pressure cuff (Table 2-3), how to accurately obtain the measurement, and which site to choose to accurately assess blood pressure. Refer to Box 2-3 for important considerations related to accurate blood pressure measurement.

Oscillometric devices are commonly used to measure blood pressure in a variety of settings, including clinics, ambulatory, home, and acute care (Muntner et al., 2019). Many of these devices have additional integrated equipment, such as a thermometer and pulse oximetry, to perform multiple vital sign measurements.

Regardless of the method used to measure blood pressure, health care providers must ensure the use of careful, accurate technique to avoid errors in blood pressure measurement (Muntner et al., 2019; Pickering et al., 2005; Whelton et al., 2018). Box 2-4 identifies potential sources of blood pressure measurement error.

Various sites can be used to assess blood pressure. The brachial artery and the popliteal artery are used most commonly. This skill discusses using the brachial artery site to obtain a blood pressure measurement.

At times, it is necessary to assess a patient for orthostatic hypotension (postural hypotension). Assessment for orthostatic hypotension may be accomplished using either an automated, electronic oscillometric blood pressure device or the auscultatory method of measuring blood pressure. Box 2-5 outlines the procedure to assess for orthostatic hypotension.

Assessment

Assess the brachial pulse, or the pulse appropriate for the site being used. Assess for an intravenous infusion or breast or axilla surgery on the side of the body corresponding to the arm used. Assess for the presence of a cast, arteriovenous shunt, or injured or diseased limb. If any of these conditions are present, do not use the affected arm to monitor blood pressure. Assess the size of the limb so that the appropriate-sized blood pressure cuff can be used (see Table 2-3). Assess for factors that could affect blood pressure reading, such as the patient's age, physical activity, weight, fluid balance, medications, and presence of disease and/or health conditions. Note baseline or previous blood pressure measurements. Assess the patient for pain. If the patient reports pain, give pain medication as ordered before assessing blood pressure. If the blood pressure is taken while the patient is in pain, make a notation concerning the pain if the blood pressure is elevated.

Actual or Potential Health Problems and Needs

Many actual or potential health problems or needs may require the use of this skill as part of related interventions. An appropriate health problem or need may include:

• Impaired Cardiac Output
• Hypertension risk
• Hypotension risk

Outcome Identification and Planning

The expected outcome to achieve when measuring blood pressure is that the patient's blood pressure is measured accurately without injury. Other outcomes may be appropriate depending on the patient's health problems or issues.

Implementation

Action	Rationale
1. Check the prescribed interventions or plan of care for frequency of blood pressure measurement. More frequent measurement may be appropriate based on nursing judgment.	Provides for patient safety.
2. Perform hand hygiene and put on PPE, if indicated.	Hand hygiene and PPE prevent the spread of microorganisms. PPE is required based on transmission precautions.
3. Identify the patient.	Identifying the patient ensures the right patient receives the intervention and helps prevent errors.
4. Close the curtains around the bed and close the door to the room, if possible. Discuss the procedure with the patient and assess patient's ability to assist with the procedure. Validate that the patient has relaxed for several minutes.	This ensures the patient's privacy. Explanation relieves anxiety and facilitates cooperation. Activity immediately before measurement can result in inaccurate results.
5. Put on gloves, if indicated.	Gloves prevent contact with blood and body fluids. Gloves are usually not required for measurement of blood pressure, unless contact with blood or body fluids is anticipated.
6. Select the appropriate arm (or alternate site) for measurement and blood pressure cuff (refer to Table 2-3).	Decision on measurement site and cuff size is based on the nurse's assessment of individual patient circumstances. Incorrect cuff size contributes to the most frequent error in measurement in nonacute care settings (Muntner et al., 2019).
7. Have the patient assume a comfortable lying or sitting position with the forearm supported at the level of the heart and the palm of the hand upward (Figure 2). If the measurement is taken in the supine position, support the arm with a pillow. In the sitting position, support the arm yourself or by using the bedside table. If the patient is sitting, have the patient sit back in the chair so that the chair supports their back. In addition, make sure the patient keeps the legs uncrossed.	The position of the arm can have a major influence when the blood pressure is measured; if the upper arm is below the level of the right atrium, the readings will be too high. If the arm is above the level of the heart, the readings will be too low (Muntner et al., 2019; Pickering et al., 2005). This position places the brachial artery on the inner aspect of the elbow so that the bell or diaphragm of the stethoscope can rest on it easily. Support for the patient's arm prevents isometric exercise that will affect the blood pressure level (Muntner et al., 2019). If the back is not supported, the diastolic pressure may be elevated falsely; if the legs are crossed, the systolic pressure may be elevated falsely (Muntner et al., 2019; Pickering et al., 2005).
8. Expose the brachial artery by removing garments or move a sleeve if it is not too tight, above the area where the cuff will be placed.	Clothing over the artery interferes with the ability to hear sounds and can cause inaccurate blood pressure readings. A tight sleeve would cause congestion of blood and possibly inaccurate readings (Muntner et al., 2019).
9. Palpate the location of the brachial artery. Center the bladder of the cuff over the brachial artery, about midway on the upper arm, so that the lower edge of the cuff is about 2.5 to 5 cm (1 to 2 inches) above the inner aspect of the elbow (Figure 3). Line up the artery marking on the cuff with the patient's brachial artery. The tubing should extend from the edge of the cuff nearer the patient's elbow (Figure 4).	Pressure in the cuff applied directly to the artery provides the most accurate readings. If the cuff gets in the way of the stethoscope, readings are likely to be inaccurate. A cuff placed upside down with the tubing toward the patient's head may give a false reading.
10. Wrap the cuff around the arm smoothly and snugly, and fasten it (Figure 5). Do not allow any clothing to interfere with the proper placement of the cuff.	A smooth cuff and snug wrapping produce equal pressure and help promote an accurate measurement. A cuff wrapped too loosely results in an inaccurate reading.
11. Turn on the machine. If the machine has different settings for infants, children, and adults, select the appropriate setting. Push the start button. Instruct the patient to hold the limb still and refrain from speaking.	Keeping the limb still and refraining from talking provide for accurate measurement of blood pressure levels (Muntner et al., 2019).
12. Wait until the machine beeps and the blood pressure reading appears. Note the reading (Figure 6).	A beep signals the completion of reading.
13. Remove the cuff from the patient's limb and clean and store the equipment.	Cleaning of equipment prevents transmission of microorganisms and prepares equipment for future use.
14. Remove gloves, if worn. Perform hand hygiene. Cover the patient and help them to a position of comfort.	Removing gloves properly reduces the risk for infection transmission and contamination of other items. Hand hygiene prevents the spread of microorganisms. Covering and positioning the patient ensures patient comfort.
15. Remove additional PPE, if used. Perform hand hygiene.	Proper removal of PPE reduces the risk for infection transmission and contamination of other items. Hand hygiene deters the spread of microorganisms.

Evaluation

The expected outcome has been met when the blood pressure has been measured accurately without injury and minimal patient discomfort.