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Assessing accurate BP measurement

Size and technique matter!

Coogan, Neil MSN, MBA, RN-BC, CEN; Marra, April RN, CAPA; Lomonaco, Elizabeth A. BSN, RN, CAPA

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doi: 10.1097/01.NURSE.0000461838.55540.6e
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ACCORDING TO THE CDC, 67 million U.S. adults, or 31% of the population, have hypertension, and only about half of them have it under control.1 About 20% of the U.S. population have undiagnosed hypertension.2 In addition, almost 30% of adults have prehypertension, which raises the risk of hypertension.1

Accurately measuring a patient's BP is essential for early recognition and management of hypertension or prehypertension. However, the procedure for measuring BP is frequently performed inaccurately: Many clinicians don't consistently follow best practices established by the American Heart Association (AHA).4

This article describes how clinicians at one facility identified a problem with BP measurement in one unit, developed an evidence-based practice (EBP) project to investigate the issue, and initiated practice changes based on AHA guidelines.

Why so important?

One of the most commonly performed procedures in nursing, BP measurement is a skill taught early in nursing school, yet it's sometimes trivialized as a less-than-important task in today's busy healthcare settings. However, an inaccurate measurement in a patient with hypertension may lead to failure to accurately diagnose the disorder and begin treatment. Conversely, an inaccurately high reading for a patient with prehypertension or normotension may lead to overtreatment with unnecessary medications.

At our facility, two nurses in the ambulatory surgical unit (ASU) identified a clinical problem as a result of observing some clinicians' BP measurement techniques when assessing patients in the unit. Reevaluation of BP readings using the proper technique revealed differences in the readings on some patients. We took the lead to assess the need for a practice change and reeducation for clinicians in the unit. Considering the high volume of patients seen in the unit and the number and mix of nursing staff, this topic became a unit-specific priority.

Utilizing our facility's adopted Iowa Model of Evidence-Based Practice, we created our population-intervention-comparison-outcome question: “What are the BP measurement techniques used by the ASU nurses compared with the AHA best practice standards in determining an accurate BP reading?”8 We formed an EBP project team, including a clinical nurse educator who acted as mentor and coach. With the assistance of the medical librarian, current research and relevant literature was assembled, critiqued, and synthesized. Following the literature review, the team determined that proper BP measurement reeducation was needed.

Targeting selected outcomes

The team designated selected outcomes based on these best practices criteria from the AHA's 2005 guidelines:

  • The cuff must be placed on bare skin.
  • The patient should rest quietly for at least 5 minutes before BP measurement.
  • The patient's forearm must be supported at the level of the right atrium.
  • The patient should sit with feet flat on the floor and back supported.
  • The BP cuff must be the proper size for the patient: cuff bladder length 80% of arm circumference; width at least 40% of arm circumference.
  • The cuff should be placed 1 in above the elbow (2 to 3 cm above the antecubital fossa).
  • The patient and nurse should be silent during the measurement procedure.4

Standard procedure also calls for palpation of the brachial artery in the antecubital fossa. If the BP reading is taken manually, the cuff is inflated at least 30 mm Hg above the point at which the radial pulse is no longer palpable.

Are nurses following the guidelines?

Two members of the team conducted a pre- and posteducation evaluation-through-observation study. The evaluation measured compliance against the AHA's best-practice guidelines. The team members observed the staff silently, without their knowledge, to avoid the Hawthorne effect (performance is better because the subject knows he or she is being watched).

This project was considered a process improvement initiative and didn't require IRB approval. The team complied with ethical principles of confidentiality and anonymity. No names of staff or patients were recorded during the data collection, analysis, or report writing.

In phase I of the study, the observers used a checklist to collect data on nursing staff measuring BP in the unit (n = 54). They manually recorded the date and time and documented how well clinicians adhered to AHA standards. We found, for example, that 87% of staff didn't choose a cuff size that was appropriate for the patient, and about 94% of staff didn't keep the patient's arm at the level of the patient's heart during measurement.

Providing continuing education

After phase I, several in-person, 1-hour, didactic continuing education programs were designed and offered as a teaching strategy for unit staff development. The content emphasized the rationale for each AHA practice standard. A simulation scenario demonstrated the psychomotor steps involved in accurately choosing and applying a proper size cuff and showed how the patient should be positioned for an accurate measurement. Two trifold tabletop posters were provided to reinforce key points. Using a model, one poster displayed a pictorial guide for correct cuff placement and patient body position. The other poster listed the steps that the team followed in the EBP process and the results of phase I of the observational study.

Follow-up and follow-through

As part of the follow-up to the program, we conducted one-on-one teaching while engaging in staff discussion about the need to change clinical practice. We provided constructive feedback on individual performance for several nurses.

Educational wall posters for each patient room, produced by our medical media department, acted as reminders about proper procedures to follow when measuring BP. The posters were strategically placed at each bedside in the ASU. Pre-op patients and alert post-op patients and families benefitted from reading the posters, which also contain education about a healthy lifestyle and BP management. In addition, an educational trifold was designed and developed for nursing staff as a pocket reminder of the practice guidelines.

Preobservation study results compared with postobservation study results

Dramatic improvement

The posteducation evaluation-through-observation phase II study followed the same methodology as the preeducation evaluation. A checklist was again used to collect the data by observing nurses measuring BP (n = 54). The team members summarized the data (see Preobservation study results compared with postobservation study results).

The posteducation observation study revealed dramatic improvement in the knowledge and skills needed for proper BP measurement in order to obtain an accurate reading. The AHA's recommendations, as outlined in the project teaching strategies, were closely followed by clinicians on the pilot unit.

Many nurses had been surprised to find out that their BP measurement techniques didn't meet practice standards. The participants displayed enthusiasm, acceptance, and reflection, despite the fact that BP measurement is a basic clinical skill. Patients and families expressed satisfaction (to their caregivers) in knowing that the clinical staff obtains accurate BP measurements. Patients appreciated being informed about the proper method that a clinician should follow in obtaining their readings.

Remember the basics!

This EBP project demonstrated that clinician retraining and competency on correct BP measurement techniques done on a consistent basis is essential, as recommended by the AHA.4 The AHA also recommends retraining of all BP observers for proper measurement technique every 6 months.4

This refocus on practice is facilitated through:

  • reeducation and ongoing training on the proper BP measurement techniques every 6 months in order to hard-wire best practice.
  • user-friendly bedside educational tools for clinical staff.
  • readily available tools and resources, such as BP cuffs in various sizes, bedside tables for arm rest, and patient education materials on prehypertension and hypertension.
  • topic inclusion as part of the ongoing nursing orientation program held for nurses new to the facility.
  • staff awareness and peer support and influence.

As nurses, we act as advocates for patients and strive to provide the highest quality care by basing practice on the best available evidence. The EBP strategies implemented in this unit and facility heightened staff awareness about the risks and potential consequences of inaccurate BP measurements. The AHA's best practice standards for BP measurement are now applied throughout the practice setting.


1. CDC. Vital signs: prevalence, treatment, and control of hypertension—United States, 1999-2002 and 2005-2008. MMWR Morb Mortal Wkly Rep. 2011;60(4):103–108.
2. Roger VL, Go AS, Lloyd-Jones DM, et al. Heart disease and stroke statistics—2012 update: a report from the American Heart Association. Circulation. 2012;125(1):e2–e220.
3. Giles TD, Materson BJ, Cohn JN, Kostis JB. Definition and classification of hypertension: an update. J Clin Hypertens (Greenwich). 2009;11(11):611–614.
    4. Pickering TG, Hall JE, Appel LJ, et al. Recommendations for blood pressure measurement in humans and experimental animals: part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research. Circulation. 2005;111(5):697–716.
    5. National Institutes of Health. National Heart, Lung, and Blood Institute. Who is at risk for high blood pressure? 2012.
      6. Hing E, Hall MJ, Ashman JJ, Xu J. National Hospital Ambulatory Medical Care Survey: 2007 outpatient department summary. Natl Health Stat Report. 2010;(28):1–32.
        7. Guide to Community Preventive Services. Cardiovascular disease prevention and control: team-based care to improve blood pressure control. 2014.
          8. Titler MG, Kleiber C, Steelman VJ, et al. The Iowa Model of Evidence-Based Practice to promote quality care. Crit Care Nurs Clin North Am. 2001;13(4):497–509.
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