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Let’s talk blood pressure. We all know how to do it but seldom do PTs actually take blood pressure. You know who you are. Taking a blood pressure reading is a pretty basic skill among physical therapists. It is taught in entry-level programs and many students arrive at PT school already knowing how to take a blood pressure measurement. Despite its simple implementation, it is rarely used outside of acute care hospital settings. Why is it important for our patients, even in the manual PT world? Cardiovascular disease remains the number one cause of death for Americans with hypertension as a known predisposing factor to cardiovascular and kidney disease (1,2). Furthermore, we know that pre-hypertension is a predisposing factor to hypertension (1-4). Pre-hypertension falls in a range of 120-139/80-89 mmHg. Currently in the US, 25% of adults are pre-hypertensive and 33% are fully hypertensive (1-4). Men lead women in hypertension prevalence by age up until the 65-74 age bracket where women take over. Blacks and caucasians lead hispanics in prevalence by ethnicity. Recent research has shown that physical therapists working in home health manage to stumble across patients frequently who have not received a pre-hypertension or hypertension diagnosis from their physician but demonstrate pre-hypertensive readings (68.1% of 763 charts) or hypertensive readings (8.5% of 763 charts) (5). In addition, in outpatient orthopedic settings, current literature shows that 23.6% of patients (n = 87) were found to have hypertensive readings across multiple visits and that 62.1% (n = 87) were found to be either pre-hypertensive or hypertensive (6). Knowing that pre-hypertension and hypertension is going undiagnosed among our patients, we need to be more vigilant about taking vitals especially if we want to truly cement our position not only as primary care practitioners but also in the realms of preventative medicine and population health. Here are a couple ways to up your blood pressure game:
- Make sure you are actually performing measurements correctly. Patients should be seated with their feet flat on the floor, preferably after being in this position for a few minutes. The back should be unsupported with legs and arms uncrossed. You should obviously not grab a reading right after the patient walks into the clinic. The right upper extremity is the optimal choice whenever possible and the arm should be placed in full extension. This places the arm in an anatomical position to allow for the brachial artery to be closest to the surface of the skin which will help you hear the volume of Korotkoff sounds. The arm should be at the same level as the heart, not above resting on your shoulder or below resting on a table or chair.
- Manual cuffs actually need to be calibrated at a minimum every 2 years and ideally every 6 months. I bet you didn’t know that, did you? I learned this a few weeks ago at a continuing education course about blood pressure held at Oakland University in Michigan. Cuffs need to be hooked up to an old school Mercury-based reference device. A read on your cuff of ± 3 mmHg compared to the calibration tool indicates a miscalibrated cuff. Very recent research looking at cuffs used by PTs in 12 outpatient clinics, home health PTs and from cuffs used by entry-level DPT students revealed that only about 75% of manual cuffs were properly calibrated (7-9). Unfortunately due to their Mercury content, these calibration devices are becoming increasingly rare; sometimes with as few as 1 device per state, hidden in some university storage closet somewhere. If you’ve been using the same cuff for a few years, the easiest way to ensure you have a calibrated cuff is to pitch it and buy a new one.
- Inappropriate choice of cuff is the #1 error when taking a blood pressure reading (1). The width of your cuff should cover 40% of the total circumference of the upper arm and 66-80% of the distance measured between the elbow and the shoulder. When you use a small cuff, you are more likely to obtain a false higher reading and vice versa for smaller cuffs.
- When beginning your measurement, most people believe that the cuff should be inflated to about 30 mmHg above the assumed or last known systolic reading. The proper method is actually known as the Maximal Cuff Inflation Level (MIL) and is a complete reversal of how most of us were taught to take blood pressure. Follow these steps to perform the MIL and a proper blood pressure reading:
- Palpate the brachial (or radial) pulse, distal to where you intend to place the cuff. Use your 2nd or 3rd finger to palpate.
- Inflate the cuff until you can no longer hear the pulse, then slowly deflate until it returns. The return of the pulse is the estimated systolic pressure.
- Add 30 mmHg to the estimate and re-inflate as rapidly as possible to this number.
- Deflate slowly and consistently (gold standard is a decrease of 2 mmHg per beat) and listen for the sound to reappear, confirming your initial systolic estimate.
- Continue deflating until you hear the sound disappear. This is your diastolic pressure.
- Avoid reinflating as much as possible.
Author: Alan Fredendall, SPT
- 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 professions from the Subcommittee of Professionals and Public Education of the American Heart Association Council on High Blood Pressure Research. Hypertension. 2005; 45(1): 142-161.
- Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The JNC7 complete report. Hypertension. 2003; 42: 1206-1251.
- Ostchega Y, Yoon SS, Hughes J, Louis T. Hypertension awareness, treatment, and control-continued disparities in adult: United States, 2005-2006. U.S. Department of Health and Human Services. NCHS Data Brief. Hyattsville, MD: National Center for Health Statistics. 2008.
- Vasan RS, Larson MG, Leip EP, et al. Impact of high normal blood pressure on the risk of cardiovascular disease. N Engl J Med. 2001; 345: 1291-1297.
- Arena S, Drouin J, Thompson K, Black B. Prevalence of pre-hypertension and hypertension blood pressure readings among individuals case managed by physical therapists in the home health care setting. Cardiopulmonary Physical Therapy. 2014; 25(1): 18-22.
- Kasinskas C, Wood R, Koch M. Blood pressure monitoring in outpatient physical therapy clinics: should it be performed routinely? Cardiopulmonary Physical Therapy. 2011; 22(4): 31.
- Arena S, Bacyinski A, Simon L, Peterson E. Aneroid blood pressure manometer calibration rates of devices used in home healthcare. Home Healthcare Now. January 2016: 34(1); 23-28.
- Arena S, Simon L, Peterson E. Aneroid blood pressure manometer calibration rates in physical therapy curricula. Cardiopulmonary Physical Therapy. April 2016: 27(2); 56-61.
- Arena S, Simon L, Bacyinski A. Aneroid blood pressure device calibration rates in home health care, outpatient rehabilitation and doctor of physical therapy education programs. Platform Presentation: Combined Sections Meeting. Home Health Section. Anaheim, CA. February 2016.