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Licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.
Bookshelf ID: NBK596728
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Open Resources for Nursing (Open RN); Ernstmeyer K, Christman E, editors. Nursing Skills [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2023.
3.1. BLOOD PRESSURE INTRODUCTION
Learning Objectives
• Accurately measure and document blood pressure using American Heart Association standards
• Adapt the procedure to reflect variations across the life span
• Recognize and report significant deviations from blood pressure norms
The accurate measurement of blood pressure is important for ensuring patient safety and optimizing body system function. Blood pressure measurements are used by health care providers to make important decisions about a patient’s care. Blood pressure measurements help providers make decisions about whether a patient needs fluids or prescription medications. It is crucial to follow the proper steps to obtain a patient’s blood pressure to ensure the care team has accurate data to help make health care decisions and determine a plan of care.
3.2. BLOOD PRESSURE BASICS
What is Blood Pressure?
A blood pressure reading is the measurement of the force of blood against the walls of the arteries as the heart pumps blood through the body. It is reported in millimeters of mercury (mmHg). This pressure changes in the arteries when the heart is contracting compared to when it is resting and filling with blood. Blood pressure is typically expressed as the reflection of two numbers, systolic pressure and diastolic pressure. The systolic blood pressure is the maximum pressure on the arteries during systole, the phase of the heartbeat when the ventricles contract. Systole causes the ejection of blood out of the ventricles and into the aorta and pulmonary arteries. The diastolic blood pressure is the resting pressure on the arteries during diastole, the phase between each contraction of the heart when the ventricles are filling with blood.[1]
Blood pressure measurements are obtained using a stethoscope and a sphygmomanometer, also called a blood pressure cuff. To obtain a manual blood pressure reading, the blood pressure cuff is placed around a patient’s extremity, and a stethoscope is placed over an artery. For most blood pressure readings, the cuff is usually placed around the upper arm, and the stethoscope is placed over the brachial artery. The cuff is inflated to constrict the artery until the pulse is no longer palpable, and then it is deflated slowly. The American Heart Association (AHA) recommends that the blood pressure cuff be inflated at least 30 mmHg above the point at which the radial pulse is no longer palpable. The first appearance of sounds, called Korotkoff sounds, are noted as the systolic blood pressure reading. Korotkoff sounds are named after Dr. Korotkoff, who first discovered the audible sounds of blood pressure when the arm is constricted.[2] The blood pressure cuff continues to be deflated until Korotkoff sounds disappear. The last Korotkoff sounds reflect the diastolic blood pressure reading.[3] It is important to deflate the cuff slowly at no more than 2-3 mmHg per second to ensure that the absence of pulse is noted promptly and that the reading is accurate. Blood pressure readings are documented as systolic blood pressure/diastolic pressure, for example, 120/80 mmHg.
Abnormal blood pressure readings can signify an area of concern and a need for intervention. Normal adult blood pressure is less than 120/80 mmHg. Hypertension is the medical term for elevated blood pressure readings of 130/80 mmHg or higher. See Table 4.2 for blood pressure categories according to the 2017 American College of Cardiology and American Heart Association Blood Pressure Guidelines.[4] Prior to diagnosing a person with hypertension, the health care provider will calculate an average blood pressure based on two or more blood pressure readings obtained on two or more occasions.
For more information about hypertension and blood pressure medications, visit the “Cardiovascular and Renal System” chapter in Open RN Nursing Pharmacology.
Hypotension is the medical term for low blood pressure readings less than 90/60 mmHg.[5] Hypotension can be caused by dehydration, bleeding, cardiac conditions, and the side effects of many medications. Hypotension can be of significant concern because of the potential lack of perfusion to critical organs when blood pressures are low. Orthostatic hypotension is a drop in blood pressure that occurs when moving from a lying down (supine) or seated position to a standing (upright) position. When measuring blood pressure, orthostatic hypotension is defined as a decrease in blood pressure by at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing. When a person stands, gravity moves blood from the upper body to the lower limbs. As a result, there is a temporary reduction in the amount of blood in the upper body for the heart to pump, which decreases blood pressure. Normally, the body quickly counteracts the force of gravity and maintains stable blood pressure and blood flow. In most people, this transient drop in blood pressure goes unnoticed. However, some patients with orthostatic hypotension can experience light-headedness, dizziness, or fainting. This is a significant safety concern because of the increased risk of falls and injury, particularly in older adults.[6] Orthostatic hypotension is also commonly referred to a postural hypotension. When obtaining orthostatic vital signs, the pulse rate may also be collected. If the pulse increases by 30 beats/minute or more while the patient stands (or sits if unable to stand), this indicates a significant change.
Orthostatic Vital Signs: Please follow the following actions when obtaining Orthostatic Vital Signs:
1. Have the patient stand upright for 1 minute if able
2. Obtain the blood pressure measurement while the patient stands using the same arm and the same equipment as the previous measurement that was taken with patient lying or sitting.
3. Obtain the radial pulse again.
4. Repeat the blood pressure and radial pulse measurements again at 3 minutes. Waiting several minutes before repeating the measurements allows time for the autonomic nervous system to compensate for blood volume shifts after position change in the patient without orthostatic hypotension.
5. If the patient has symptoms that suggest orthostatic hypotension but doesn’t have documented orthostatic hypotension, repeat blood pressure measurement.
Pro-Tip: Remember – some patients may not demonstrate significant falls in blood pressure until they stand beyond 3 minutes
Table 4.2
Blood Pressure Categories[7]
| Blood Pressure Category | Systolic mm Hg (upper #) | Diastolic mm Hg (lower #) |
|---|---|---|
| Normal | < 120 and | < 80 |
| Elevated | 120-129 and | < 80 |
| Stage 1 | 130-139 or | 80-89 |
| Stage 2 | At least 140 or | > or = 90 |
| Hypertensive Crisis | > 180 and/or | > 120 |
View Ahmend Alzawi’s Korotkoff Sounds Video on YouTube[8]
Equipment to Measure Blood Pressure
Manual Blood Pressure
A sphygmomanometer, commonly called a blood pressure cuff, is used to measure blood pressure while Korotkoff sounds are auscultated using a stethoscope. See Figure 3.1[9] for an image of a sphygmomanometer.
Figure 3.1
A Sphygmomanometer
There are various sizes of blood pressure cuffs. It is crucial to select the appropriate size for the patient to obtain an accurate reading. An undersized cuff will cause an artificially high blood pressure reading, and an oversized cuff will produce an artificially low reading. See Figure 3.2[10] for an image of various sizes of blood pressure cuffs ranging in size for a large adult to an infant.
Figure 3.2
Sizes of Blood Pressure Cuffs
The width of the cuff should be 40% of the person’s arm circumference, and the length of the cuff’s bladder should be 80–100% of the person’s arm circumference. Keep in mind that only about half of the blood pressure cuff is the bladder and the other half is cloth with a hook and loop fastener to secure it around the arm.
View Ryerson University’s Accurate Blood Pressure Cuff Sizing Video on YouTube[11]
Automatic Blood Pressure Equipment
Automatic blood pressure monitors are often used in health care settings to efficiently measure blood pressure for multiple patients or to repeatedly measure a single patient’s blood pressure at a specific frequency such as every 15 minutes. See Figure 3.3 [12] for an image of an automatic blood pressure monitor. To use an automatic blood pressure monitor, appropriately position the patient and place the correctly sized blood pressure cuff on their bare arm or other extremity. Press the start button on the monitor. The cuff will automatically inflate and then deflate at a rate of 2 mmHg per second. The monitor digitally displays the blood pressure reading when done. If the blood pressure reading is unexpected, it is important to follow up by obtaining a reading using a manual blood pressure cuff. Additionally, automatic blood pressure monitors should not be used if the patient has a rapid or irregular heart rhythm, such as atrial fibrillation, or has tremors as it may lead to an inaccurate reading.
Figure 3.3
Automatic Blood Pressure Monitor
References
- 1.
- This work is a derivative of Vital Sign Measurement Across the Lifespan - 1st Canadian Edition by Ryerson University licensed under CC BY 4.0 ↵.
- 2.
- 3.
- This work is a derivative of Clinical Procedures for Safer Patient Care by British Columbia Institute of Technology licensed under CC BY 4.0 ↵.
- 4.
- American College of Cardiology. Whelton, P. K., Carey, R. M., Aronow, W. S., et al. (2018, May 7). 2017 guidelines for high blood pressure in adults. https://www
.acc.org/latest-in-cardiology /ten-points-to-remember /2017/11/09/11/41 /2017-guideline-for-high-blood-pressure-in-adults ↵. [PubMed: 29466540] - 5.
- National Heart, Lung, and Blood Institute. (n.d.). Low blood pressure. https://www
.nhlbi.nih .gov/health-topics/low-blood-pressure ↵. - 6.
- U.S. National Library of Medicine. (2020, June 23). Orthostatic hypotension. https://ghr
.nlm.nih.gov /condition/orthostatic-hypotension ↵. - 7.
- American College of Cardiology. Whelton, P. K., Carey, R. M., Aronow, W. S., et al. (2018, May 7). 2017 guidelines for high blood pressure in adults. https://www
.acc.org/latest-in-cardiology /ten-points-to-remember /2017/11/09/11/41 /2017-guideline-for-high-blood-pressure-in-adults ↵. [PubMed: 29466540] - 8.
- Alzawi, A. (2015, November 19). Korotkoff+Blood+Pressure+Sights+and+Sounds SD. [Video]. YouTube. All rights reserved. https://youtu
.be/UfCr_wUepxo ↵. - 9.
- 10.
- “BP-Multiple-Cuff-Sizes.jpg” by British Columbia Institute of Technology (BCIT) is licensed under CC BY 4.0. Access for free at https://opentextbc
.ca /vitalsign/chapter/how-is-blood-pressure-measured/ ↵. - 11.
- Ryerson University. (2018, March 21). Blood pressure - Accurate cuff sizing. [Video]. YouTube. All rights reserved. https://youtu
.be/uNTMwoJTfFE ↵. - 12.
3.3. BLOOD PRESSURE ASSESSMENT
Subjective Assessment
Before taking a person’s blood pressure, it is important to determine if they have a history of elevated blood pressure or if they are taking any blood pressure medication. It is helpful to establish a baseline by asking their usual blood pressure reading or reviewing previous records in their chart. It is also important to determine if there are any arm restrictions such as those due to a fistula, mastectomy, stroke, or IV line before measuring blood pressure. See Table 3.3a for sample interview questions associated with the subjective assessment of blood pressure.
Table 3.3a
Interview Questions for Subjective Assessment of Blood Pressure
| Interview Questions |
|---|
| Have you ever been diagnosed with an elevated blood pressure? • Please describe the treatment. |
| Are you currently taking any medications, herbs, or supplements for your blood pressure? • Please identify what you are taking. |
| Do you have any restrictions on taking blood pressure in your arms such as those due to a fistula or mastectomy? • Please describe the restrictions. |
| What is your usual blood pressure reading? |
| Do you take your blood pressure at home? • What time of day do your take the reading? • Where do you obtain the reading from (i.e., cuff location and placement)? • What is the range of results that you commonly receive in the home setting? |
| If applicable: • Are you experiencing any symptoms related to high or low blood pressure now, such as a severe headache, dizziness with position changes, light-headedness, or fainting episodes? |
Objective Assessment
Inspection
Before obtaining a blood pressure reading, it is important to inspect and consider conditions that would prevent the use of a blood pressure cuff, such as a history of clots or presence of current clots, lymphedema, wounds, a fistula, or current IV access lines. If these conditions exist, obtain the blood pressure in an alternative extremity.
Life Span Considerations
Children
Blood pressure measurement is not routinely performed on children under the age of 3 unless there are cardiac concerns.
Older Adults
Blood pressure measurements are sometimes difficult to hear in older adults. For patients who are clinically stable and Korotkoff sound auscultation is difficult, doppler auscultation may be helpful.
Clinical Tips
Blood pressure assessment should be completed after the patient has rested for a minimum of five minutes. If the patient has ingested caffeine or nicotine within 30 minutes before measuring blood pressure, this should be documented with the reading.
There are times when it is difficult to auscultate Korotkoff sounds. As a result, the care team must decide what alternate measures could be performed to obtain accurate blood pressure results. For patients who are critically ill or hemodynamically unstable, an arterial line may be placed directly into an artery to measure blood pressure. This is an invasive procedure and is not used for routine monitoring.
See Table 3.3b for a comparison of expected versus unexpected findings when assessing blood pressure.
Table 3.3b
Expected Versus Unexpected Findings on Blood Pressure Assessment
| Assessment | Expected Findings | Unexpected Findings (Document or notify provider if this is a new finding*) |
|---|---|---|
| Inspection | Not applicable | Evidence of fistula, lymphadenopathy, IVs, clots, deficits from a stroke, or other restrictions from using the arm for blood pressure readings should be documented and communicated in handoff reports for continuity of care. |
| Auscultation | Able to identify Korotkoff sounds and blood pressure reading within expected parameters | Unable to identify Korotkoff sounds or blood pressure readings are outside of expected parameters. |
| Palpation | Able to palpate pulse | Unable to palpate pulse. |
| *CRITICAL CONDITIONS to report immediately | Blood pressure readings are outside of expected parameters for this patient’s age or the patient has symptoms associated with a blood pressure that is out of range. |
3.4. SAMPLE DOCUMENTATION
Sample Documentation of Expected Findings
Blood pressure 120/80 on the left arm with the patient in a seated position using a manual cuff.
Sample Documentation of Unexpected Findings
Blood pressure reading on right arm 160/95. Blood pressure reading left arm 154/93 after patient rested 5 minutes. Reports no history of hypertension and currently not taking any blood pressure medications. Denies dizziness, headache, visual changes, or lightheadedness. Dr. Smith notified of all of above and order for furosemide 20 mg PO now received.
3.5. CHECKLIST FOR MANUAL BLOOD PRESSURE
Use the checklist below to review the steps for obtaining a “Manual Blood Pressure.”
Note: The two-step method includes the first step of inflating the cuff and palpating the radial pulse to estimate the systolic blood pressure before obtaining the blood pressure reading. This procedure is based on current AHA recommendations.[1]
Video Review of Assessing Blood Pressure:[2]
Steps
Disclaimer: Always review and follow agency policy regarding this specific skill.
- 1.
Gather supplies: blood pressure cuff and stethoscope. (Select an appropriately sized cuff for the patient.)
- The width of the cuff should be 40% of the person’s arm circumference, and the length of the cuff’s bladder should be 80–100% of the person’s arm circumference.
- 2.
Perform safety steps:
- Perform hand hygiene.
- Check the room for transmission-based precautions.
- Introduce yourself, your role, the purpose of your visit, and an estimate of the time it will take.
- Confirm patient ID using two patient identifiers (e.g., name and date of birth).
- Explain the process to the patient and ask if they have any questions.
- Be organized and systematic.
- Use appropriate listening and questioning skills.
- Listen and attend to patient cues.
- Ensure the patient’s privacy and dignity.
- Assess ABCs.
- 3.
Cleanse the stethoscope and blood pressure cuff prior to placing it on the patient’s skin.
- 4.
Place the patient in a relaxed reclining or sitting position. The patient should be seated quietly for at least five minutes in a chair prior to blood pressure measurement. Ask the patient which arm they prefer to use. Be aware of conditions that contraindicate the use of an arm for blood pressure measurement, such as a previous mastectomy or the presence of a fistula. During the procedure, both feet should be on the floor and the arm should be supported at heart level.
- 5.
Adapt the procedure to life span considerations of the patient.
- 6.
Remove or rearrange clothing so the cuff and the stethoscope are on bare skin.
- 7.
Center the bladder of the blood pressure cuff over the brachial artery with the lower margin 1″ above the antecubital space. Fit the cuff evenly and snugly. Palpate the brachial artery in the antecubital space.
- 8.
Locate the radial pulse.
- 9.
Inflate the cuff rapidly (while palpating the radial or brachial pulse) to the level at which pulsations are no longer felt and inflate the cuff 30 mmHg above the palpated pressure or the patient’s usual blood pressure. Note the level and rapidly deflate the cuff; wait 30 seconds.
- 10.
With the eartips of the stethoscope placed downward and forward, place the bell/diaphragm lightly on the brachial artery and rapidly inflate the cuff to 30 points above where the brachial or radial pulse is no longer felt.
- 11.
Deflate the cuff gradually at a constant rate by opening the valve on the bulb (2-3 mm Hg/second) until the first Korotkoff sound is heard. Note the systolic pressure.
- 12.
Continue to deflate the cuff slowly at 2 mm Hg/second. Note the point at which Korotkoff sounds disappear completely as the diastolic pressure.
- 13.
Deflate the cuff completely and remove thecuff from the patient’s arm.
- 14.
Inform the patient of the blood pressure reading.
- 15.
Cleanse the stethoscope and blood pressure cuff.
- 16.
Perform proper hand hygiene.
- 17.
Ensure five safety measures before leaving the room:
- CALL LIGHT: Within reach
- BED: Low and locked (in lowest position and brakes on)
- SIDE RAIL: Secured
- TABLE: Within reach
- ROOM: Risk-free for falls (scan room and clear any obstacles)
- 18.
Document findings and report significant deviations from norms according to agency policy.
References
- 1.
- Chobanian, A. V., Bakris, G. L., Black, H. R., Cushman, W. C., Green, L. A., Izzo, J. L., Jones Jr., D. W., Materson, B. J., Oparil, S., Wright Jr., J., Roccella, E. J., & National High Blood Pressure Education Program Coordinating Committee. (2003). Seventh report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Hypertension, 42(6), 1206-1252. ↵10.1161/01.HYP.0000107251.49515.c2 [PubMed: 14656957] [CrossRef]
- 2.
- Open RN Project. (2021, November 11). Assessing Blood Pressure. [Video]. YouTube. Video licensed under CC-BY-4.0. https://youtu
.be/VvLtwcpa7GA ↵
3.6. SUPPLEMENTARY VIDEO OF BLOOD PRESSURE ASSESSMENT
Video Review of Blood Pressure Assessment[1]
References
- 1.
- RegisteredNurseRN. (2019, June 4). Blood pressure measurement: How to check blood pressure manually. [Video]. YouTube. All rights reserved. Video used with permission. https://youtu
.be/UGOoeqSo_ws ↵.
3.7. LEARNING ACTIVITIES
Learning Activities
(Answers to “Learning Activities” can be found in the “Answer Key” at the end of the book. Answers to interactive activity elements will be provided within the element as immediate feedback.)
You are a nurse assigned to help with blood pressure screenings at the local senior center. What elements must be considered when selecting equipment and location of blood pressure assessment?
“2 Step Blood Pressure Sequencing Activity” by Susan Jepsen for Lansing Community College are licensed under CC BY 4.0
Orthostatic Blood Pressure Management Activity” by Susan Jepsen for Lansing Community College are licensed under CC BY 4.0
Test your clinical judgment with an NCLEX Next Generation style question: Chapter 3 Assignment 1
Test your clinical judgment with an NCLEX Next Generation style question: Chapter 3 Assignment 2
Test your clinical judgment with an NCLEX Next Generation style question: Chapter 3 Assignment 3
III. GLOSSARY
- Diastole
The phase between each contraction of the heart when the ventricles are filling with blood.
- Diastolic blood pressure
The resting pressure of blood on the arteries between each cardiac contraction.
- Hypertension
Elevated blood pressure over 130/80 mmHg in an adult.
- Hypotension
Decreased blood pressure less than 90/60 mmHg in an adult.
- Korotkoff sounds
The audible sounds of blood pressure named after Dr. Korotkoff who discovered them.
- Orthostatic hypotension
A decrease in blood pressure by at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing from a seated or lying position.
- Sphygmomanometer
A device used to measure blood pressure and is commonly referred to as a blood pressure cuff.
- Systole
The phase of the heartbeat when the left ventricle contracts and pumps blood into the arteries.
- Systolic blood pressure
The maximum pressure of blood on the arteries during the contraction of the left ventricle of the heart referred to as systole.
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