Chapter 5: Blood Pressure
Hypertension
Chronically elevated blood pressure is known clinically as hypertension. It is defined as chronic and persistent blood pressure measurements of 140/90 mm Hg or above (OER #2) in the adult. However, the specific measurement in which hypertension is diagnosed depends on many factors. As per Hypertension Canada (Nerenberg, et al., 2018), some of these factors include whether it is the first or second visit to have blood pressure assessed and whether the blood pressure is assessed using automatic or manual measurement devices. It is always important to look at the most current guidelines related to hypertension. See Table 5.3 for the guidelines related to management, including monitoring and treatment, recommended by Hypertension Canada (Nerenberg, et al., 2018).
Hypertension is typically a silent disorder, so hypertensive clients may not recognize the seriousness of their condition and not adhere to their treatment plan. The result is often a heart attack or stroke. Hypertension may also lead to an aneurysm (ballooning of a blood vessel caused by a weakening of the wall), peripheral arterial disease (obstruction of vessels in peripheral regions of the body), chronic kidney disease, or heart failure. (OER#2)
Common errors in measurement and natural fluctuations in blood pressure can result in readings that erroneously suggest hypertension. Some of the errors are due to the operator (i.e., the healthcare provider) and others are due to client anxiety and situational determinants. As a healthcare provider, it is important to review your technique to assess possible measurement errors and assess the client for factors that could elevate blood pressure. If the client’s blood pressure is elevated, repeat the measurement for accuracy and take the blood pressure in the opposite arm.
Because hypertension is a silent disorder, healthcare providers measure blood pressure at regular intervals. The intervals depend on the client’s health status and risk factors. Before a diagnosis of hypertension is made, blood pressure is monitored over days, weeks, or months either in the office using an automatic blood pressure machine, or at home using an ambulatory blood pressure machine.
Clients demonstrating features of a hypertensive urgency or emergency (e.g., hypertensive encephalopathy, acute coronary syndrome, acute ischemic stroke, intracranial hemorrhage) are diagnosed as hypertensive and treated immediately.
Points to Consider
It is important to note the distinction between elevated blood pressure and a diagnosis of hypertension. Elevated blood pressure refers to an isolated reading, whereby the client has an elevated finding. Hypertension refers to a clinical diagnosis whereby the client has met the criteria for chronic elevated blood pressure. Hypertension will precipitate a treatment protocol, whereas an elevated finding may just require monitoring. See Table 5.3 below for more information on making a determination of hypertension.
Guidelines to Determine Hypertension
Hypertension Canada (Leung, et al., for Hypertension Canada, 2017) states that when assessing chronic high blood pressure, readings must be done under the following conditions:
- No acute anxiety, stress, or pain
- No caffeine, smoking, or nicotine in the preceding 30 minutes
- No use of substances containing adrenergic stimulants such as phenylephrine or pseudoephedrine (may be present in nasal decongestants or ophthalmic drops)
- Bladder and bowel comfortable
- No tight clothing on arm or forearm
- Quiet room with comfortable temperature
- Rest for at least five minutes before measurement
- Ask the client to stay silent prior and during the procedure
Technique Tips
If one of the above conditions is not met, the blood pressure is still taken, but the healthcare provider must take it into consideration. If the blood pressure is elevated, it needs to be repeated to assess the possibility of hypertension.
See Table 5.3 for the guidelines related to management, including monitoring and treatment, in the adult, recommended by Hypertension Canada (Nerenberg, et al., 2018). These recommendations are based on in-office visit one. At least two or more readings are taken during the same visit. If assessing blood pressure, the first reading is discarded and the latter two readings are averaged. You should wait one minute in between blood pressure measurements (Hypertension Canada, 2020). Additionally, multiple readings may be needed when the client has an arrhythmia (Hypertension Canada, 2020)
Table 5.3: Hypertension Canada Guidelines
| Finding | Management |
|---|---|
| Visit 1 Office BP Measurements
Manual BP averaged reading ≥130–139/85–89 mm Hg (high-normal)
|
Annual follow-up appointments are recommended so that trends and/or increases in blood pressure are assessed.
|
| Visit 1 Office BP Measurements
Manual BP averaged reading ≥140/90 mm Hg (high)
Automatic BP reading ≥135/85 mm Hg (high)
|
A health history and physical examination are performed.
Visit two is scheduled within one month of visit one.
If clinically indicated, diagnostic tests are scheduled prior to visit two to assess cardiovascular risk factors (see Table 5.4 for modifiable and non-modifiable risk factors) and search for target organ damage (e.g., cerebral vascular, eyes, kidneys, coronary arteries).
External, modifiable factors that can increase blood pressure are assessed and removed if possible (certain prescription drugs and other substances like sodium, licorice root, alcohol, and street drugs).
Out of office blood pressure measurements (e.g., ambulatory or home blood pressure measurements) are performed before visit two. White coat syndrome/hypertension is diagnosed if the out of office blood pressure measurements are within the normal range, and pharmacologic treatment is not initiated.
|
| Visit 1 Office BP Measurements
Automatic or manual BP averaged reading ≥180/110 mm Hg
|
Hypertension is diagnosed and immediate intervention is required. |
The healthcare provider assesses a client’s cardiovascular risk factors for atherosclerosis and hypertension. These risk factors are categorized as modifiable and non-modifiable. See Table 5.4 for an overview of risk factors adapted based on Hypertension Canada guidelines (Leung, et al., for Hypertension Canada, 2017)
Table 5.4: Modifiable and Non-modifiable Risk Factors
| Non-modifiable | Modifiable |
|---|---|
|
|
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Part of this content was adapted from OER #2 (as noted in brackets above):
© Apr 10, 2017 OpenStax Anatomy and Physiology. Textbook content produced by OpenStax Anatomy and Physiology is licensed under a Creative Commons Attribution License 4.0 license. Download for free at http://cnx.org/contents/7c42370b-c3ad-48ac-9620-d15367b882c6@12
