Blood Pressure

How to Take an Accurate BP Measurement

ORLANDO—Correctly measuring blood pressure (BP) both in the office and at home is a critical aspect of proper BP management. During his presentation at Consultant360’s Cardiometabolic Risk Summit 2019, F. Wilford Germino, MD, reviewed the facets of BP measurement that can affect the measurement’s accuracy.

Select the Correct Type of Device

A manual measurement device should be used to record BP in patients who find automated devices too painful, whereas a wrist device should be used when an upper-arm measurement cannot be obtained. When recording BP with the latter, ensuring proper forearm positioning is key. 

Regardless of which device is used, though, all BP measurements need to be validated on a 6- to 12-month cycle. And Dr Germino pointed out that the aneroids that are currently available can only be validated, not calibrated.  

Prepare the Patient for the Test

Leading up to the test, clinicians should instruct patients to avoid caffeine, exercise, and smoking for at least 30 minutes before the test. Patients should also empty their bladders before the test—not doing so can affect the reading by up to 10 mm HG. Clinicians should also have patients relax in a chair—not on the examination table—with their feet on the floor and back supported for more than 5 minutes. Finally, there should be no conversing between the practitioner and the patient during the rest or measurement period.

Ensure Proper Positioning

During the test, the patient’s arm should be supported on a surface and rested at the heart level. Clinicians should also ensure that the cuff itself is positioned correctly, with the middle of the cuff being placed on the patient’s upper arm.

Ensure Proper Cuff Size

The cuff’s bladder should go around 80% of the arm, according to Dr Germino. The following cuff sizes should be used for the corresponding arm circumference range:

  • Small adult cuff size: 22 cm to 26 cm
  • Adult cuff size: 27 cm to 34 cm
  • Large adult cuff size: 35 cm to 44 cm
  • Adult thigh cuff size: 45 cm to 52 cm

Not adhering to the proper BP measurement protocol can lead to errors in the reading, Dr Germino said. In fact, for every inch that an arm is improperly placed, the BP may be impacted by 2.5 mm HG.

Validate At-Home Monitors

Dr Germino suggests that patients who are self-monitoring their BP should purchase validated devices and that the devices be validated at least once a year. Clinicians should also have patients bring their at-home device to the appointment and observe the patients take their BP to ensure that it is being done correctly at home.

Analyzing the Measurements

While obtaining a proper BP measurement is key, knowing how to analyze the reading is just as important. According to Dr Germino, when making a treatment decision, the arm with the higher reading should be used. Additionally, if the measurement shows an elevated BP, a treatment decision should not be made based on that one reading.  

—Colleen Murphy

Reference:

Germino FW. The importance of accurate blood pressure management. Talk presented at: Consultant360’s Cardiometabolic Risk Summit 2019; October 24-26, 2019; Orlando, FL.