AHA Issues Scientific Statement on Accurate Blood Pressure Readings

Categories of BP Among Adults

• Normal: SBP <120 mm Hg and DBP <80 mm Hg
• Elevated: SBP 120-129 mm Hg and DBP <80 mm Hg
• Hypertension Stage 1: SBP 130-139 mm Hg or DBP 80-89 mm Hg
• Hypertension Stage 2: SBP ≥140 mm Hg or DBP ≥90 mm Hg

Guidelines for Conducting Ambulatory BP Monitoring (ABPM)

• Training
  • Provide knowledge about BP measurements that can be obtained through ABPM
  • Provide training in the specialized equipment, techniques, and devices needed to conduct ABPM
  • Provide training in preparing patients for ABPM
  • Train clinicians to prepare/initialize devices for recording
  • Train clinicians to fit the device, cuff, and tubing on the patient
  • Train clinicians in ABPM software and downloading data

• Devices, cuffs, and equipment
  • Use validated upper-arm cuff oscillometric devices
  • Use a cuff that is the appropriate size for the patient’s nondominantarm
  • Use new or recharged batteries

• Patient preparation and instruction
  • Provide instruction on what ABPM involves and how to cope with the procedure
  • Inform patients that ABPM may disrupt sleep
  • Inform patients to avoid showering and swimming, and tell them not to remove the ABPM device, cuff, and tubing
  • Tell patients to follow their usual daily activities, but to keep their body still during each BP measurement
  • Provide a brief summary of ABPM procedures on a reference card
  • Teach the patient how to refit the cuff if it migrates from its ideal position
  • Show the patient how to place the device on the bed or beneath a pillow during sleep
  • Show the patient how to turn off the device in case of malfunction
  • Provide instructions for filling out a diary documenting sleep and awakening times, times of antihypertensive medication intake, occurrence of symptoms, and meals

• Frequency and number of readings
  • Every 15-30 minutes during the 24 hour period (48-96 total readings)

• Duration of monitoring
  • Ideal period is 24 hours

• Analyzing readings
  • Commonly-recommended criteria are ≥20 readings during the day and ≥7 readings during the night, but an ABPM recording with fewer may still be valid
  • For each period (day, night, and 24 hours), calculate the average of all readings

Guidelines for Home BP Monitoring (HBPM)

• Patient training provided by clinicians
  • Provide information on hypertension diagnosis and treatment
  • Provide information on proper device selection
  • Teach patients how to measure their own BP
  • Instruct patients to bring the HBPM device and BP readings to healthcare visits
  • Teach patients that individual BP readings may vary greatly during the monitoring period

• Preferred devices and cuffs
  • A validated upper-arm cuff oscillometric device
  • A device that can automatically store all readings
  • A device that can print results or electronically send BP values to clinicians
  • A cuff that is appropriately sized for the patient’s arm circumference

• Best practices
  • Preparation
    • Have an empty bladder
    • Rest in seated position for ≥5 minutes
    • Do not talk or text
  • Position
    • Sit with back supported
    • Keep both feet flat on the floor
    • Do not cross legs
    • Place BP cuff on bare arm
    • Place BP cuff directly above the antecubital fossa
    • Place the center of the bladder of the cuff over the arterial pulsation of the bare upper arm
    • Pull cuff taut around the bare upper arm, with comparable tightness at the top and bottom edges
    • Support the cuffed art on a flat surface

• Number of readings
  • Take 2 readings at least 1 minute apart in the morning before taking antihypertensive medications and 2 readings at least 1 minute apart in the evening before bed

• Duration of monitoring
  • Preferred monitoring period is ≥7 days with a minimum of 3 days
  • Monitoring conducted over consecutive days is ideal

• Analyzing readings
  • The average of all readings should be calculated for each monitoring period

Summary of Scientific Statement on the Measurement of BP in Humans

• BP components
  • Several BP components, including SBP, DBP, pulse pressure, and mean arterial pressure, are associated with cardiovascular disease (CVD) risk
  • Most guidelines use SBP and DBP to define hypertension

• BP measurement in the office
  • While the auscultatory BP method has been the traditional approach, it is being increasingly replaced by the oscillometric method
  • Aneroid sphygmomanometers require frequent calibration (every 2-4 weeks for handheld devices and every 3-6 months for wall-mounted devices)
  • Automated office blood pressure (AOBP) devices should be considered for measuring office BP
  • Office BP should be measured ≥2 times per visit
  • Even when AOBP is being used, clinician training is integral for accurate BP measurement

• 24-h ABPM
  • ABPM is the preferred approach for assessing out-of-office BP
  • The main indications for ABPM are to detect white-coat hypertension and masked hypertension
  • ABPM is the preferred approach to assess nocturnal hypertension, which is common among black patients

• HBPM
  • HPBM can be used to assess out-of-office BP when ABPM is not available or accepted by the patient. It can be used to detect white coat hypertension and masked hypertension
  • Many HBPM devices have not been validated; clinicians should only recommend devices that have been validated
  • By itself, HBPM has a limited effect on BP control, but it is effective in reducing BP when used in conjunction with supportive interventions
  • Encourage patients to use HBPM devices that automatically store readings or transmit them to their clinician

• Special BP measurement techniques
  • While devices that measure BP at the wrist have been validated, they face many challenges in obtaining an accurate reading
  • A preliminary analysis of wireless BP monitors showed poor accuracy

This article originally appeared on The Cardiology Advisor