From the Guidelines
To diagnose blood pressure, ambulatory blood pressure monitoring (ABPM) is the best method, as it provides the most accurate diagnosis by measuring blood pressure at regular intervals over 12 to 24 hours while patients go about their normal activities and while they are sleeping. According to the USPSTF recommendation statement published in the Annals of Internal Medicine in 2015 1, ABPM is the reference standard for confirming the diagnosis of hypertension. This method is preferred over office blood pressure measurement due to its ability to provide a more accurate representation of a patient's blood pressure throughout the day.
When using ABPM, measurements are typically taken at 20- to 30-minute intervals, and elevated ambulatory systolic blood pressure is consistently and significantly associated with increased risk for fatal and nonfatal stroke and cardiovascular events, independent of office blood pressure 1. In addition to ABPM, home blood pressure monitoring (HBPM) can also be used to confirm a diagnosis of hypertension, using a fully automated oscillometric device to record measurements taken from the patient's brachial artery.
For initial screening, blood pressure should be measured by a healthcare professional using a sphygmomanometer (blood pressure cuff) on the upper arm, following proper technique, such as sitting with back supported, feet flat on floor, arm supported at heart level, and avoiding talking, using electronic devices, or having a full bladder during measurement, as outlined in the 2019 AHA/ACC clinical performance and quality measures for adults with high blood pressure 1. However, ABPM remains the gold standard for diagnosing hypertension due to its high accuracy and ability to provide a comprehensive picture of a patient's blood pressure patterns.
Some key points to consider when diagnosing blood pressure include:
- Measuring blood pressure at least twice during a visit, with readings taken 1-2 minutes apart
- Using ABPM or HBPM to confirm a diagnosis of hypertension
- Recording all readings and bringing them to the healthcare provider
- Avoiding factors that can affect blood pressure measurements, such as talking, using electronic devices, or having a full bladder during measurement
- Establishing a consistent timing of measurements to help establish the patient's true baseline blood pressure.
From the Research
Diagnosing Blood Pressure
To diagnose blood pressure, several methods can be employed, including manual and automated measurements.
- Manual blood pressure measurement using an aneroid sphygmomanometer and a stethoscope is considered the gold standard for non-invasive BP measurement 2.
- Accurate measurement of blood pressure is essential to identify hypotension or hypertension and to inform subsequent management and treatment decisions 2.
- Factors that can influence the accuracy of blood pressure measurement include patient positioning, cuff size, arm position, and correct use of the stethoscope 2.
Automated Blood Pressure Measurement
Automated blood pressure measurement is an alternative to conventional manual measurement, and it has been shown to be more accurate and reliable 3.
- Automated office blood pressure (AOBP) involves multiple blood pressure readings taken with a fully automated device with the patient resting quietly alone 3.
- AOBP is preferable to routine manual office blood pressure in that it exhibits improved accuracy and a stronger relationship to both ambulatory blood pressure and target organ damage 3.
- The use of automated devices can also reduce digit preference, minimize observer bias, and facilitate the recording of multiple blood pressure readings 3.
Special Considerations
When measuring blood pressure, it is essential to consider special client groups and to use the appropriate equipment and techniques 4, 5.
- The choice of sphygmomanometer depends on the clinical need, and clinicians should be aware of the limitations of automated devices 4.
- Manual blood pressure measurement skills should still be taught to healthcare professionals, particularly when treatment protocols are based on accurate blood pressure readings 4, 5.
Advanced Blood Pressure Assessment
In addition to traditional sphygmomanometry, there are other devices and methods that can provide more information and give a better picture of the patient's true hypertensive status 6.
- These devices can help to assess the degree of blood pressure control and the risk of end-organ damage, and they may be useful in diagnosing and managing hypertension 6.