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Kardiovaskulárny systém

Table of contents
Assessment of vital signs – Blood pressure
Authors: Veronika Rajki, PhD, Pál Bakó
The blood pressure
  • Blood pressure is the pressure of blood on the walls of the arteries as the heart pumps blood around the body.
  • The maximum blood pressure during contraction of the ventricles: systolic pressure
  • The minimum pressure during relaxation: diastolic pressure
  • Unit of measurement: mmHg
1 mmHg = 133.322 Pa (0.133 kPa)

The history of blood pressure measurement

  • William Harvey (1578-1657) discovered blood circulation in 1616.
  • Christopher Wren, in 1653, pioneered the practice of IV injection.
  • Boyle described the inverse relationship between a gas's pressure (P) and volume (V), noting that during inhalation, the volume increases due to the diaphragm contracting, and the pressure decreases.
  • Giovanni Alfonso Borelli (1608-1679) proposed that the heart contracts to force blood into the arterial system. He suggested that the compression of the heart's chambers occurs because the lateral walls come closer rather than because the ventricles become shorter. 
  • Stephen Hales, in 1727, was the first to determine arterial blood pressure by measuring the rise in a column of blood in a glass tube inserted into an artery. In 1896, Riva-Rocci introduced the upper arm cuff to measure systolic blood pressure.
  • In 1905, Nicolai Sergeivich Korotkoff added the auscultatory technique, allowing for the measurement of both systolic and diastolic blood pressure.
Physiological characteristics of arterial blood pressure
  • Stroke volume ~ 70 ml
  • Cardiac output = stroke volume × heart rate
    • Blood pressure = cardiac output × peripheral resistance
  • Ejection fraction = SV (stroke volume)/EDV (End diastolic volume
  • Basal metabolism comprises only 10%–20% of total O2 consumption.
  • Myocardial oxygen consumption is normally around 75% and is determined by wall tension and contractility. 
Factors affecting blood pressure (BP)
  • Sex
  • Age: BP tends to rise from birth to puberty, then sets at 120/80 mmHg.
  • Family history, race, and genetics
  • Physical exertion
  • Body position: there might be a sudden drop in blood pressure (about 15–20 mmHg) when we stand from a seated or prone (lying down) position.
  • Emotional status: anxiety, fear, and stress can increase BP
  • Hormonal effects
  • Pain
  • Circadian rhythm
  • Diet
  • Medications
  • Pulmonary/cardiac factors
  • Coffee consumption and/or smoking
The diagnosis of hypertension (high blood pressure)
  • Patient’s history, complaints, and clinical signs (e.g., risk factors of hypertension and history of organ damage caused by hypertension, patient’s complaints and symptoms, physical abnormalities, previous antihypertensive therapy and its success rate, adherence rate, and history of secondary hypertension).
  • Physical examination (body weight, height, body mass index (BMI), abdominal circumference. First, a complete physical examination is recommended, including blood pressure measurement. Identifying neurological signs and abnormalities, confirming cardiovascular complications (heart murmur, dysrhythmia, detecting murmur over carotid, subclavian, renal, and femoral arteries, and palpability of peripheral blood vessels).
  • Laboratory tests 
Recommended basic lab tests and other examinations
Hemoglobin and/or hematocrit
Fasting blood glucose level
Serum total cholesterol, LDL and HDL cholesterol
Serum triglyceride
Potassium, sodium
Serum uric acid
Serum creatinine, eGFR
Liver functions
Urinalysis: via microscopic examination, or using the urine protein dipstick test that measures the presence of proteins, such as albumin in a urine sample. Ideally the albumin-to-creatinine ratio (ACR) should also be tested.
12 lead ECG
Fundus examination in grade 2 and grade 3 hypertension
Additional laboratory tests, and imaging
HbA1c (if fasting blood glucose level is > 5.6 mmol/L or in case of previously diagnosed diabetes mellitus)
Quantitative proteinuria (if the qualitative test is positive)
Echocardiography (to confirm the heart’s structural and functional abnormalities, if these affect treatment options)
Holter monitoring (arrhythmias, ischemia or if any of these are suspected)
Carotid ultrasound (to confirm the buildup of plaque and/or stenosis, especially in case of cerebrovascular disease or in other vascular disorders)
Peripheral artery ultrasound (for the detection of abdominal aortic aneurysm, examination of the renal arteries)
Abdominal ultrasound (to examine the size and structure of the kidneys, the morphology of the adrenal glands, and if there is a postrenal obstruction)
Pulse-wave velocity (PWV) to define arterial stiffness
Ankle-brachial index (ABI) is crucial for diagnosing peripheral artery disease (PAD).
Cognitive function test
Brain scans (CT/MRI) (especially if cerebrovascular disease or cognitive decline is mentioned in the patient’s history)
Methods of measuring blood pressure
  • Invasive or continuous or direct arterial blood pressure monitoring
It detects intra-arterial changes in real-time.  
Invasive blood pressure monitoring is a part of extended intensive care monitoring. One of the most significant advantages of invasive BP monitoring is the ability to obtain an accurate picture of the patient's hemodynamic status at all times. This type of measurement is the gold standard of blood pressure measurement, which gives accurate beat-to-beat information. With the help of the transducer, the monitor displays a waveform, preferably with a calibrated scale and a digital numeric display of systolic, diastolic, and mean arterial pressures (MAP).
The usual method of invasive blood pressure monitoring involves percutaneously inserting a plastic catheter into a peripheral artery. The catheter is connected via high-pressure plastic tubing to an electronic pressure transducer and display unit. 
The common sites for arterial placement are the radial, ulnar, brachial, axillary, posterior tibial, dorsalis pedis, and femoral arteries. The radial artery is the most preferred catheterization site. The less frequently used site is the brachial artery due to poor treatment adherence, and the femoral artery cannulation has also been associated with higher infection risk. 
The steps of the procedure:
  1. Preparing the patient involves providing information, obtaining consent, and positioning the patient (e.g., placing the patient supine with extended limbs).   
  2. Preparing the setting: provide protective pads and sheets.
  3. Preparing the components: arterial cannulas (8 cm long for the radial and brachial artery, 16 cm long for the femoral artery), transducer, 500 mL or 1000 mL pressure bag filled with saline (0.9% sodium chloride) solution, protective pads, sheets, monitor and cables, ultrasound device, gel, and probe cover.
Arterial cannula with Flowswitch
  • Artery puncture: assist the physician (handle over the sterile tools, cleanse the puncture area with the betadine swab, isolate the puncture site, manage cut down if required, apply sterile dressing). 
  • Assembly the invasive blood pressure monitoring system and evacuate all air. Tighten the connecting components before removing the air bubbles. 
  • Connect the transducer to the dome while the pressure bag is on; otherwise, the dome may become damaged. Then, provide 300 mmHg pressure in the bag. 
  • Connect the cannula to the evacuated monitoring system. 
  • Zeroing: The pressure transducer should be placed at the heart level; by convention, it is set at the right atrium level. If the patient’s position changes or the system is temporarily disconnected (e.g., if the patient is transferred), zeroing should be performed at least once during each shift.    
Components of the intra-arterial blood pressure monitoring system
Pressure bag
Pressure transducer
with flush
Arterial cannula
Non-compressible, fluid filled tubing
Invasive arterial blood pressure
The arterial cannula allows blood samples to be taken following the principles of antisepsis. Use the 3-way tap, which should be flushed in every direction after each phlebotomy. For blood samples, use a pre-filled heparin lock flush syringe.  
3-way tap
  • Non-invasive blood pressure measurement
The cuff is wrapped around the middle of the upper arm to surround the brachial artery
  • Auscultatory blood pressure measurement
When the cuff is placed on the upper arm and inflated above the anticipated systolic pressure, it compresses the brachial artery and halts blood flow. Then, by gradually deflating the cuff at a rate of around 2–3 mmHg per second, the artery reopens, and the pulse can be felt again. 
Inflatable cuff
Pressure gaugeStethoscope
Cuff pressure between
80 and 120 mmHg
Cuff pressure
>120 mmHg
Cuff pressure
< 80 mmHg
When the cuff is inflated so that it stops arterial flow,
no sound can be heard through a stethoscope placed
over the brachial artery distal to the cuff.
Korotkoff sounds are created by pulsatile blood flow
through the compressed artery.
Blood flow is silent when the artery is
no longer compressed.
The manual blood pressure measurement technique is generally associated with measuring brachial arterial pressure when Korotkoff sounds are heard through a stethoscope applied over the brachial artery.
Palpatory method
  • The palpatory method allows us to determine only the systolic pressure during the deflation of the cuff placed over the brachial artery. 
Types of sphygmomanometers
The mercury sphygmomanometer
  • Components: glass tube with mercury, mercury gauge or scale, inflatable cuff, pneumatic ball or hand bulb, release valve, tubing. The ideal cuff bladder width is ≥ 40 percent of the patient's arm circumference.
  • Inflate the cuff with the hand bulb.
  • As the pressure in the cuff changes, so does the pressure on the mercury column. Hence, the blood pressure value is represented by the height of the mercury column in mmHg or kPa.1 Hgmm=133.322 Pa=0.133 kPa
  • Mercury sphygmomanometers are considered the gold standard. 
  • Other sphygmomanometers must be calibrated against a standardized and validated reference mercury sphygmomanometer once a year.
  • Accidental mercury spill from a sphygmomanometer is dangerous.
  • The European Commission banned the sale of mercury measuring devices to the public in 2009 because mercury is a toxic metal. Still, the prohibition has several exceptions for mercury-containing sphygmomanometers.   
The mercury free sphygmomanometer
  • Desk sphygmomanometer meets the provisions of all applicable EU Directives.
  • Works both on the principle of the oscillometric measurement method and the auscultation method.
  • The BP monitor has an LED-backlit mercury-free LCD Display digital scale.
  • It allows manual cuff inflation and deflation.
  • Most models use batteries.
  • These devices are provided with an adult cuff, but smaller cuff sizes for children are also available.
  • The manual aneroid (using no liquid) sphygmomanometer works similarly to the mercury sphygmomanometer.
  • It has the accuracy of mercury sphygmomanometers.
  • Mercury sphygmomanometers take up a relatively lot of space. 
Aneroid sphygmomanometer
  • Smaller size, easy to use.
  • Standard, aneroid gauge
  • Mercury-free device
  • It is almost as accurate as the mercury sphygmomanometer.
  • Available in both rotary valve and push-button versions.
  • Single or double-tube versions are available.
  • Specific devices are available only for right-handed users. 
  • It has to be regularly calibrated (every year). 
  • It can quickly fail, which may show lower BP rates.  
Semi-automatic or automated sphygmomanometers
  • Oscillometric devices produce a digital readout and work on the principle that blood flowing through an artery between systolic and diastolic pressures causes vibrations in the arterial wall, which can be detected and transduced into electrical signals.
  • Easy to use.
  • Cuffs can be placed around the upper arm, the wrist, or a finger.
  • Of the automatic devices, the upper arm cuff is the most reliable. 
  • In some cases, the wrist cuff may be appropriate, e.g., for people living alone or if the available upper arm cuff size is unsuitable. However, it is recommended only for preventive or occasional measurements, not for patients with cardiovascular disease, whose blood pressure needs to be measured accurately and regularly. 
  • One great advantage is that, after calibration, the patient can measure blood pressure values and record the results if needed or regularly in the comfort of their own home (they usually have a memory for 60–100 measured rates). The software can also save the medication applied to some devices. This helps to build therapeutic compliance and enhance patient safety
  • The rules for blood pressure measurement are the same as for the previously presented measuring devices; the only difference is that a stethoscope is unnecessary, so the patient or family member can do the measurement independently. 
  • In the case of semi-automatic sphygmomanometers, we start the measurement after turning the device on. Then, the cuff is inflated manually. In the case of an automated sphygmomanometer, the device begins measuring immediately after being turned on. A built-in compressor inflates the cuff, and the device displays the systolic and diastolic rate and pulse.   
  • With modern smart devices, measured data can be easily synchronized and organized into tables to generate statistics. The data can also be shared online with people involved in the treatment. 
  • Failure of automated or semi-automatic sphygmomanometers is more challenging to recognize, which makes these devices less accurate.
  • Recalibration at certain intervals is advisable to ensure constant reliability. These devices lose accuracy over time, so a clinically validated device is needed. 
Ambulatory Blood Pressure Measurement (ABPM)
  • Oscillometric device.
  • A blood pressure cuff of the appropriate size should be placed on the patient's non-dominant arm. This cuff is connected to a mobile phone-sized device that can be attached to the neck or waist. 
  • It allows blood pressure measurement over 24 hours at set intervals (usually every 15–30 minutes during active periods and 20–30 minutes during resting periods) and records the measured heart rate.  
  • Blood pressure measurement can also be initiated when the patient feels it is necessary, for example, when symptoms occur.
  • It provides a more accurate blood pressure profile and information about the nature of hypertension and the body's reactions to rest and stress.
  • It can be used to determine the diurnal (circadian) variations of blood pressure and the characteristics of BP fluctuations during the day and night.
  • The device stores the measured data, which can be downloaded to a computer after the examination.
  • It can be determined if the patient’s complaints are blood pressure-related.
  • It can detect temporary spikes in blood pressure lasting only a few minutes and persistent elevations. 
  • It is also helpful to control antihypertensive therapy.
  • It can exclude white-coat hypertension.
  • It provides help for individualized medication and adequate drug adjustment.
  • Based on the information obtained during the examination, recommendations for adequate and personalized lifestyle changes can be made, and dietary advice and individual exercise therapy can be offered for the patient.
  • Never immerse the device or cuff in water or other liquid.
  • A BP diary will be provided, which must be completed during the test.
  • The test is risk-free and does not cause pain or discomfort, but inflating the cuff can cause discomfort and tightness for the patient, disturbing their sleep at night.  
  • No special preparation is required for the test.
  • It should be noted in advance if the patient works alternating shifts, and it should be clarified when the patient has their active (working) and passive (resting) periods during the 24-hour measurement so that the physician does not diagnose the patient as non-dipper (e.g., due to working a night shift). The dipper phenomenon occurs when blood pressure decreases by >10% in the resting period compared to the active period.  
  • ABPM has no KNOWN contraindications.
Patient information on ABPM
Patient information has four main topics:
  1. Preparing for the ABPM
  2. Fitting the ABPM device
  3. The test itself
  4. Post-test period, evaluation of blood pressure results
  1. Preparing for the ABPM
  • Usually, in the early morning hours before the test, patients should shower at home, as the device is not waterproof. Thus, it must not be removed during the 24-hour measurement (neither for bathing nor sleeping at night). 
  • Loose clothing is required because the device's cuff must be placed directly on the patient's arm, under the clothing.
  • If the patient has sensitive skin, it is recommended to wear a thin shirt or blouse under the cuff (a disposable blood pressure cuff barrier or a single-use blood pressure cuff can also be used), which does not affect the accuracy of the blood pressure measurement but prevents problems might arise from the long-term wearing of the cuff (e.g., sweating, itching, pain).  
  • Using a belt for appropriate clothing is recommended, as the device must/can also be attached to a belt.
  • The ABPM device is in a small pouch, the straps of which can be loosened to make the device more comfortable during the day. 
  • Any batteries that run down during the monitoring period must be replaced, after which measurements can continue without data loss.
  • The memory card of the device should never be removed during the test.
  • The device should only measure and record one person’s blood pressure at a time.
  • The BP diary is to be used with the device (optimally provided to the patient), and the associated documentation has to be explained to the patient. 
  • The patient has to record the following in the diary:
  • The time when the patient went to bed
  • The time when the patient got up in the morning
  • Applied medication during the 24-hour BP measurement
  • All activities (work, housework, walking, other physical activity (specified), driving, traveling, eating, watching TV, resting, sleeping) 
  • If any unusual symptom occurs (e.g., malaise, nausea), the patient can initiate an additional measurement by pressing a button, which is also displayed at that time. The symptoms, why the additional measurement was performed, and the time of the measurement must be recorded in the event log.  
  • When the patient takes their anti-hypertension medication or wants to mark any other event, they can also use a specific button. The function of this button should also be explained to the patient beforehand. In this case, the patient should always record when the button was pressed and the problem in the event log. 
  • As a safety measure, suppose the patient feels pain when the cuff squeezes their arm too hard during inflation. In that case, the patient can stop the inflation by pressing any button. After that, the device will continue to operate according to the preset data or a manual measurement start.  
  • Patients can then place the small portable device next to them in bed at night.
  1. Positioning the ABPM’s cuff
  • Use only a cuff of an appropriate size.
  • Too tight and too loose cuffs will result in an inaccurate reading, so if the cuff is tight or loose at rest, it should be adjusted so that a finger fits between the cuff and the upper arm. 
  • During the programming and fitting, which takes about 10–15 minutes, a healthcare professional will inform the patient and repeat the most important information that the patient needs to be aware of during the 24-hour measurement.
  • A test BP measurement should be taken after each fitting, and then this first measurement should be disregarded for the evaluation. 
  • Before the patient goes home:
  • The patient should sign the receipt of the device.
  • Recording of patient data in the system.
  • Some institutions need a payment of a deposit for the device.
  • The patient can then return to his/her regular daily routine, with the device automatically taking predefined and programmed measurements at specific intervals without any patient intervention. 
  1. The examination
  • The patient must proceed with their completely regular daily routine during the examination.
    • A bath or shower is not allowed (washing only), as the device cannot be exposed to water. The cuff must be kept on the upper arm at all times (2/3 of the upper arm, not sliding down to the cubital region), and it must not be loosened or removed. 
    • If the cuff does slip off, it should be removed and placed on the upper arm like the cuff of a standard sphygmomanometer. 
    • Most devices give an audible alarm (beep) if the cuff is not repositioned correctly or simply no further measurement is taken (assessed), so the 24-hour test will probably need to be repeated. 
    • The device's integrity must be maintained. Patients must ensure it is not damaged or dropped, and they should not lie on it while sleeping.   
    • Care must be taken throughout the test to ensure that the cuff tube is not twisted or blocked, preventing the airflow from being obstructed. 
    • The test should not cause any circulatory problems for the patient. However, suppose the patient experiences numbness or pain after measuring blood pressure. In that case, the cuff should be removed immediately to avoid permanent vascular or nerve damage, and the patient should report it to their physician immediately after the monitoring period.   
    • When the cuff is inflating, to avoid a failed measurement, if possible, the patient should leave their arm at an armrest, extended and supported, but she/he may move.
    •  If the patient's cuffed arm moves or the measurement fails, the device repeats the inflation. 
  • The device must be returned the following day after 24 hours; the next patient can use it.  
  1. Evaluation of the results
  • After removing the device, the data recording will be checked to ensure it was successful.
  • If the monitoring is successful, the patient will be informed of the cardiologist's subsequent evaluation. In most cases, this will be done via e-mail. Still, the results can also be obtained in person.  
  • If the measurement is unsuccessful, the 24-hour ABPM test must be repeated.
  • Specific recommendations suggest that the first and last hour of the 24 hours should not be considered when evaluating the results (when the patient is traveling to and from the doctor’s office). 
  • In light of the test results and medical history, personalized medication, dietary, and exercise therapy can be recommended, and further assessment may be advised if necessary.
Possible indications of the ABPM test
  1. Diagnostic
  • Remarkable blood pressure fluctuations during office visits
  • High blood pressure with otherwise low cardiovascular risk during office visits
  • A significant difference exists between the office SBP, DBP, and the home SBP and DBP. 
    • Exclusion of white coat hypertension (gold standard)
      • Systolic blood pressure (SBP) 140–159 mmHg, or diastolic blood pressure (DBP) 90–99 mmHg during office visits
      • Newly diagnosed hypertension
      • There is no target organ damage
    • Suspected masked hypertension
      • Hypertension in the doctor’s office
      • Normal blood pressure measured in the office, hypertension-mediated organ damage, or in case the cardiovascular risk is high
      • Both parents have hypertension
      • Target organ damage
      • Metabolic syndrome/diabetes mellitus
    • Resistant hypertension
      • Exclusion of white coat hypertension
      • For a more reliable risk stratification
  • Suspected episodic hypertension
    • In elderly
    • In patients with diabetes mellitus
    • Higher blood pressure rates at nights
    • Elevated blood pressure rates under stress and physical exertion
    • Postprandial and orthostatic hypotension in treated or untreated patients
  • Gestational hypertension
  1. Differential diagnosis
  • Sleep apnea syndrome or other suspected secondary hypertension
  • Autonomic nervous system failure (idiopathic orthostatic hypotension)
  1. Treatment
  • To control the anti-hypertensive therapy (setting individual medication, assessing the efficacy and duration of drugs) 
  • Symptoms during therapy that suggest possible hypotension
Home Blood Pressure Monitoring (HBPM) 
Over the past two decades, cost-effective HBPM has become an effective and convenient tool for screening hypertension. Non-invasive blood pressure measurement methods include auscultation, oscillometry, tonometry, and pulse wave recording and analysis. The HBPM uses the same technology as ABPM monitors but allows patients to check their blood pressure as often as they like. While the ABPM provides an unlimited number of blood pressure data over 24 hours (while the patient performs their daily routine activities), the HBPM provides blood pressure data at certain times and under specific conditions; thus, the HBPM provides stable, highly reproducible measurements and it has also been proven to be as reliable as the ABPM. 
Regular self-blood pressure measurement compared to office blood pressure measurement improves patient-physician cooperation, as more accurate BP data can be gathered from HBPM compared to measurements in the physician's office. For adequate home blood pressure measurement, a certified blood pressure monitor (sphygmomanometer) is needed (purchased in a medical supply store), and nurses must teach patients how to use the device correctly. The best position to take blood pressure is seated in a chair with feet on the floor and the arm supported so the elbow is at about heart level. The patient should remain in this position throughout the measurement.   
The inflatable part of the cuff should completely cover at least 80% of the upper arm. It should be placed on bare skin, not over a shirt.  
  • The patient should not talk during the measurement.
  • Blood pressure should be measured daily at least 3–4 times within 1–2 minutes, and all 3–4 measurements must be recorded. 
  • Measurements should be averaged only if the difference is less than 10 mmHg.
  • The first measurement should be taken immediately after waking up before taking any medication, and the second should be taken before 11:00 a.m. 
  • Patients should always take blood pressure on the same arm.
Devices used for HBPM should be clinically validated for home use. Home blood pressure monitors must be calibrated regularly (every 6 months to two years) to stay accurate. HBPM promotes medication adherence (compliance) and lifestyle changes and makes patients more aware of their condition.  
Patients must use a blood pressure diary or an electronic device (e.g., unique smartphone apps or telemedicine devices) to store or transmit measured blood pressure values for effective therapy. These devices can improve patient adherence and compliance.    
Hypertension is defined as blood pressure of 135/85 mmHg or higher when measured at home; however, an optimal blood pressure is lower than 120/80 mmHg. It is important to note that HBPM performed with most automated devices is contraindicated in patients with pulse irregularities, such as atrial fibrillation (AF). However, studies suggest that AF did not significantly impair the accuracy of oscillometric blood pressure measurement if repeated measurements were performed. 
ABPM
HBPM
Pros
Pros
  • Able to detect white coat hypertension or masked hypertension
  • Has superior prognostic value
  • Nighttime blood pressure readings
  • Real blood pressure readings
  • Additional prognostic blood pressure phenotypes
  • Additional information e.g., short-term blood pressure fluctuations
  • Able to detect white coat hypertension or masked hypertension
  • Not expensive and WIDELY available
  • Measurements at home (CALMER conditions compared to in-office measurements)
  •  Involves the patient in the management of blood pressure
  • More reproducible readings are needed, and it can detect daily blood pressure fluctuations.
Cons
Cons
  • Costly and limited accessibility
  • It can be uncomfortable for the patients
  • Assesses blood pressure when the patient is at rest
  • Possible measurement error
  • No nighttime measurements (However, recently, devices equipped with timer functions during sleep have been developed).
Non-invasive BP measurement
Tasks before the measurement
  • Half an hour before the measurement, the patient should refrain from drinking fluids (no caffeine or alcoholic beverages), eating, or smoking, and she/he has to empty her/his bladder. 
  • The patient should be left alone for 5 minutes in a quiet environment, where they can sit on a chair with back support. The patient should relax and avoid physical activity and talking. 
  • The measurement should be performed in a quiet, calm room with a normal temperature. 
Tasks during blood pressure measurement
  1. The patient should sit comfortably with their feet flat on the floor. 
  2. For the first time, measure both arms.
  3. Dependency of the arm below heart level leads to overestimating systolic and diastolic pressures, and raising the arm above heart level leads to underestimation. 
  4. Hygienic hand disinfection
  5. The forearm must also be horizontal at the level of the heart. Therefore, the arm must be supported during blood pressure measurement, which is best achieved by having the observer hold the subject's arm at the elbow.
  6. Palpate the brachial artery for a pulse.
  7. Select the correct size of the cuff and center the lower edge 2.5 cm (1 in.) above the elbow crease over the brachial artery. The cuff should not be loose or tight. Place the cuff over the bare upper arm, with the artery mark directly over the brachial artery.  
  8. Palpate the radial artery while the cuff inflates until the radial pulse disappears.
  9. Remember and record the rate when the pulse disappeared (this will be the patient’s estimated systolic blood pressure).
  10. Inflation of the cuff 30 mmHg above the previously measured systolic value.
  11. Check the stethoscope and place it over the brachial artery.
  12. Deflate the cuff slowly (2–3 mmHg/sec). Look at the sphygmomanometer gauge, and remember when you hear sounds over the brachial artery.  
  13. This is the systolic blood pressure number. Continue slowly deflating the cuff, and when you no longer hear the brachial pulse, note the number on the sphygmomanometer gauge, as that number is the patient's diastolic blood pressure number. 
  14. Deflate completely the cuff and remove it from the patient’s arm.
  15. For the first time, take at least 2 measurements at 1 or 2-minute intervals and average the values.
  16. Documentation.
  17. Hygienic hand disinfection
Tasks after blood pressure measurement
  • Put the device away.
  • Disinfect the used equipment.
  • Documentation
The rules of blood pressure measurement
  • At the first measurement, take the BP of both arms. 
  • Apply four-limb blood pressure measurement if the physician requires it (usually in patients with cardiovascular diseases).  
  • BP measurement in sitting, lying, and standing positions (it is crucial to avoid orthostatic hypotension due to rapid changes in body position).  
  • The patient should rest for at least 5 minutes before measuring.
  • The patient should avoid drinking coffee or alcohol, smoking, talking, singing, and talking for 1 hour before and during the measurement.
  • Talking raises BP by 6–7 mmHg. 
  • If you plan to take two measurements in a row, you should wait at least one minute between them to allow the pressure on the veins to release.  
  • If the patient’s blood pressure needs to be checked regularly, it should be done at the same time (at the same hour) each day.  
  • If the patient has to urinate, taking their blood pressure is not recommended because a full bladder can raise blood pressure by up to 10 mmHg. 
Do not measure blood pressure on the arm or if
  • the patient has a plaster cast or bandage.
  • The patient has an IV catheter or AV fistula.
  • The patient had a mastectomy or had axillary lymph node dissection; BP measurement should be performed on the opposite arm.
  • The patient has inflammation of the veins, thrombosis, and neuritis.
  • The patient's arm is paralyzed.  
Potential errors during blood pressure measurement
Potential errors can occur due to the device or the person taking the measurement. These errors should be detected and corrected before the measurement.
Potential errors of the device:
  • Loosened seals (the needle of the gauge will not move)
  • Incorrect zero - the gauge does not return to zero.
  • Kinked or twisted tubing (or punctured).
  • Faulty rubber ball or cuff.
  • Damaged valve.
Errors made by the examiner:
  • Incorrectly placed cuff.
  • Inappropriate blood pressure cuff:
    • Too small/narrow cuff – falsely high readings (the length of the bladder of the cuff should encircle 80% of the circumference of the upper arm)
    • Too small/narrow cuff – falsely low readings
  • Deflation of the cuff is too fast:
    • Falsely low systolic and falsely high diastolic values
  • Faulty stethoscope or tubing.
  • Palpatory method
  • Measurement on the arm, where you should not take blood pressure. 
  • Taking blood pressure induces patient complaints
  • Sequential BP measurements on the same arm.
  • Incorrect reading
  • Non-compliance with hand hygiene practices
Disinfection of the cuffs, stethoscopes, and sphygmomanometers after each measurement is not performed. Studies in the medical literature have demonstrated that many physicians’ stethoscopes are contaminated with pathogenic bacteria and could serve as a way to transmission of infection. Stethoscopes need to be disinfected using a 70% isopropyl alcohol solution.  
Ear tips can be removed from the ear tubes for thorough cleaning.
For safety, snap ear tips firmly back onto the ribbed ends of the ear tubes.
First patientSecond patientThird patient
Disinfection of the stethoscope
Disinfection of the cuff
Single use blood pressure cuffs
Recommended cuff sizes
  • For an arm circumference of 22–26 cm 12 × 22 cm (small adult/child)
  • For an arm circumference of 27–34 cm 16 × 30 cm (standard adult size)
  • For an arm circumference of 35–44 cm 16 × 36 cm (large adult)
  • For an arm circumference of 45–52 cm 16 × 42 cm (adult thigh)
Blood pressure readings
  • Normal blood pressure: systolic <120 mmHg, diastolic < 80 mmHg.
  • An increase of 20 mmHg in systolic pressure or 10 mmHg in diastolic pressure above 115/75 mmHg doubles the risk of death from cardiovascular disease.
  • Prehypertension is defined as a systolic pressure of 120–139 mmHg or a diastolic pressure of 80–89 mmHg.
  • Prehypertension is commonly referred to in Europe as high-normal BP.  
  • Low blood pressure:
    • If systolic BP is less than 100 mmHg permanently.
    • Orthostatic hypotension is a clinical finding defined by a fall in systolic blood pressure over 20 mmHg or a fall in diastolic pressure over 10 mmHg after getting up to a standing position.
    • It affects 25% of the population over 65 years of age but is also known as a complication of several diseases (e.g., diabetes)  
    • It can be diagnosed by measuring blood pressure in the standing position after having a meal.
Measuring blood pressure
Measuring blood pressure – POV
High BP
The blood pressure is measured at least twice and taken on at least three separate occasions. There should be a 1-week pause (or interval) between each set of measurements. Systolic Value: The systolic blood pressure (the higher number in a blood pressure reading) should be greater than 140 mmHg. Diastolic Value: The diastolic blood pressure (the lower number in a blood pressure reading) should be greater than or equal to 90 mmHg. 
Primary (essential) high BP:
  • High blood pressure is multi-factorial and doesn't have one specific cause, or the cause is unknown.
  • This type of hypertension accounts for 90–95% of adult cases.
  • It is associated with aging, and the prevalence of primary hypertension increases with age.
  • The inheritance pattern is unknown. 
  • Risk factors: obesity (central obesity, insulin resistance, diabetes mellitus, hypertension, dyslipidemia – metabolic X syndrome), physical inactivity, stress, excessive salt intake, smoking.
Resistant hypertension (secondary hypertension)
  • Kidney disease
  • Endocrine disorder (hyperthyroidism, diabetes mellitus)
  • Other (arteriosclerosis)
  • Medications (NSAID, corticosteroids)
  • Alcoholism, drug use
White-coat hypertension – also called isolated office or clinic hypertension:
  • When measured in the physician's office, is there a higher BP than at other times?
  • 24-hour ambulatory monitoring can be used to identify white-coat hypertension.   
Masked hypertension:
  • is defined as normal blood pressure (BP) in the clinic or office (<140/90 mmHg),
  • but an elevated BP out of the clinic (ambulatory daytime BP or home BP>135/85 mmHg).
  • It is a risk factor for coronary artery disease, acute myocardial infarction, and stroke.
Systolic blood pressure (mmHg)Diastolic blood pressure (mmHg)Table of BP readingsOptimal blood pressureNormal blood pessureHigh-normal systolic blood pressurePrimary hypertensionSecondary hypertensionStage 3 hypertensionIsolated systolic
hypertension
≥140 systolic and
≥90 diastolic
180160140130120808590100110
CategorySystolic BP
(mmHg)
Diastolic BP
(mmHg)
Optimal blood
pressure
Normal blood
pessure
High-normal BPStage 1
hypertension
Stage 2
hypertension
Stage 3
hypertension
Isolated diastolic
hypertension (IDH)
Isolated systolic
hypertension (ISH)
andand/orand/orand/orand/orand/orandand< 120< 80120-12980-84130-13985-89140-15990-99160-179100-109≥ 180≥ 110< 140≥ 90≥ 140< 90Normal and abnormal office BP categories
Definitions of Hypertension Based on Office, Ambulatory, and Home Blood Pressure Levels
Category
Systolic BP (mmHg)
Diastolic BP
(mmHg)
Blood pressure in the office
≥130
and/or
≥90
Blood pressure at home
≥130
and/or
≥85
Ambulatory blood pressure
Daytime
≥135
and/or
≥85
Nighttime (during sleeping)
≥120
and/or
≥70
24-hour
≥130
and/or
≥80
Hypertension monitoring
Baseline BP (mmHg) (a)
Follow-up (b)
Systolic
Diastolic
Normal BP
< 130
< 85
At least once every 2 years
High/Elevated
130–139
85–89
At least every year (c)
Abnormal BP Stage 1
140–159
9099
Within 2 months (c)
Stage 2
160–179
100–109
Examination, treatment and follow-up within 1 month
Stage 3
180
110
Examination, treatment and follow-up within 1 week
  1. If the systolic or diastolic category differs, follow-up should be performed within a shorter period.
  2. The frequency of monitoring may be modified based on a blood pressure value known from the patient’s history, other cardiovascular risk factors, and target organ damage.
  3. Lifestyle changes should be made. 
Non‐pharmacological nursing management of hypertension
Components of the therapy
Recommendation
Decreasing systolic BP
Weight loss
Optimal body mass index (BMI) < 25 kg/m² or abdominal circumference should be below 94 cm for men and 80 cm for women.
-5–20 mmHg/10 kg weight loss
Reducing salt intake
Reduced salt intake
< 6 g/day
-2–8 mmHg
DASH diet
Foods in the DASH diet are rich in the minerals potassium, calcium and magnesium. The DASH diet focuses on vegetables, fruits and whole grains.
-8–14 mmHg
Physical activity
Regular physical activity (30–60 min/day) 3-times per week
-4–9 mmHg
Alcohol consumption
Less than 2 drinks/day for men (25 g alcohol)
or 1 drink/day for women
(12.5 g alcohol)
-2–10 mmHg
Ankle Brachial Index (ABI)
  • A simple, painless, non-invasive test to check for peripheral artery disease (PAD) in Fontaine Stage 1 – Asymptomatic, incomplete blood vessel obstruction.
  • The diagnosis of peripheral vascular disease is based on a simple ultrasound examination, in most cases using a continuous wave (CW) Doppler device.
  • Doppler ultrasonography uses ultrasound to examine blood flow in the major arteries and veins of the arms and legs. The ankle-brachial index (ABI) is the ratio of systolic blood pressure at the ankle (dorsalis pedis artery) to that in the brachial artery. However, the short time lag between these measurements may result in differences between the measured values.  
Therefore, a more precise measurement, simultaneous blood pressure measurement in four limbs with an oscillometric blood pressure monitor, is preferred. This device measures inter-arm differences (IAD) and simultaneously detects atrial fibrillation.   
  • This method requires less time and is more comfortable for the patients.
  • Oscillometric BP device measures arterial blood pressure in the arms and legs, either on 2 limbs on the same side or all four limbs simultaneously, using the appropriate cuff sizes (upper arm and ankle cuffs are available in S, M, and L sizes). Thus, with the use of this device and method, possible errors can be avoided due to blood pressure variations. 
  • Normal range of ABI value for patients in lying position 1.0–1.4.
  • ABI values between 0.91 and 0.99 are considered borderline.
  • Severe PAD if the ABI value is lower than 0.9.
Ankle brachial index
Interpretation
Recommendation
Higher than 1.4
Calcification, noncompressible vessel
Patient should consult a vascular surgeon
1.0–1.4
Normal
None
0.9–1.0
Acceptable
None
0.8–0.9
Mild PAD
Manage risk factors
0.5–0.8
Moderate PAD
Referring the patient to a vascular surgeon or a specialist.
Lower than 0.5
Severe PAD
Referring the patient to a vascular surgeon or specialist called an angiologist.
  • Lower ABI values suggest deterioration of the vascular disease.
  • It is important to note that in patients with diabetes, the measurement of ABI may be limited due to diffuse sclerosis of the crural blood vessels.
  • This is an affordable and easy-to-use screening test and can be considered a health screening examination (mainly in primary care). 
  • The sensitivity and specificity of this test for the detection of PAD is very high, above 90%.
How to perform ankle-brachial index? 
  1. Using arterial duplex or arterial ultrasound.
  • It is a simple test during which the patient lies on their back. 
  • First, we explain the procedure to the patient. 
  • We ask the patient to remove his/her clothes from the body part that will be examined. Then, they lie down on an examination bed with their arms at heart level.  
  • The patient should be lying down for 5 minutes before the test.
  • Place an adequate-sized cuff on the patient's upper arm.
  • Take blood pressure on both limbs and document the results.
  • Palpate the artery (brachial artery) to be examined on the upper arm.
  • Place the probe in the artery after applying gel to the ultrasound probe. You should hear swishing or pulse-like sounds during the procedure.  
  • After placing the blood pressure cuff proximally, inflate it to about 20–30 mm Hg above the previously measured (and expected) systolic value until the tone or sound of the flow or Doppler signal disappears. Document the value with a cuff deflation rate of 1 mmHg/sec.  
  • When the Doppler signal re-appears, the cuff's pressure equals the brachial systolic pressure. 
  • Record the brachial systolic pressure.
  • Like the arm, measure the blood pressure above the ankle using either the posterior tibial artery or the dorsalis pedis artery. 
  • Place an adequate-sized cuff on the patient's leg.
  • Palpate the posterior tibial artery or the dorsalis pedis artery.
  • Place ultrasound gel over the examined area and the probe over the artery. During the procedure, you should hear swishing or pulse-like sounds. 
  • After placing the blood pressure cuff proximally, inflate it above the previously measured systolic value by about 20–30 mm Hg until the flow sound disappears. This value must also be documented while deflating the cuff using the same measure used for the arms until the Doppler signal reappears.   
Ankle Brachial Index (ABI) Ultrasound
Systolic pressure recorded
in the brachial artery of the arm
Ultrasound device (probe) amplifies
the sound of arterial blood flow
Systolic pressure recorded in the arteries
of the ankle after each arterial flow is located
Inflatable cuff
Doppler ultrasound device
Brachial artery
Dorsalis pedis artery
Posterior tibial artery
Blood pressure cuff
  • Record this value as well.
  • The ABI is calculated by dividing the lower limb's systolic blood pressure by the upper arm's systolic blood pressure. Physiologically, blood pressure is usually higher in the lower limb than in the arm. 
Systolic pressure >120 mmHg
Cuff pressure >108 mmHg
108120=0.9Ankle brachial index (ABI ratio)
  1. Oscillometric measurement of ankle brachial index
  • Oscillometric blood pressure monitors are readily available and easy to use.
  • First, we explain the procedure to the patient.
  • We ask the patient to remove his or her clothes from the body part that will be examined. Then, the patient lies down on an examination bed with their arms at heart level. 
  • The patient should be lying down for 5 minutes before the test.
  • Cuffs of the appropriate size for the patient are placed on the arms and legs (on the two lower and upper limbs on the same side or all 4 limbs, depending mainly on the type of device). Always follow the markings on the cuffs. 
  • After placing the cuffs, the measurement takes place automatically by pressing the Start button. 
  • After a few seconds, the blood pressure readings (both systolic and diastolic), pulse, and ABI will be displayed on the screen. 
When to perform ankle brachial index test?
An ankle-brachial index test is recommended in individuals at risk for peripheral arterial disease (PAD). In the case of suspected PAD. 
  • In case of abnormal lower limbs or murmur.
  • To establish a diagnosis of intermittent claudication and other type of PAD.
  • In poor wound healing and recurrence of ulcers in the lower limb. 
If there is a risk of PAD due to other medical disorders:
  • Coronary artery disease or other atherosclerotic vascular disease
  • Abdominal aortic aneurysm, chronic kidney disease (CKD), heart failure
Risk of PAD, but patients with no symptoms:
  • All men and women aged 65 or over, regardless of risk status
  • High-risk patients younger than 65 years: diabetes mellitus, SCORE risk 5–9%
  • Men and women over 50 years of age, who are smokers or who have a known family history of PAD
Note!
For both ultrasound and oscillometric measurement, the following may limit or even make impossible the application or use of the blood pressure cuff:
  • Limb with ulcer
  • Severe limb edema
  • Extreme obesity
  • Diabetic polyneuropathy (with hyperesthesia)
In such cases, the Toe Brachial Index (TBI) test is recommended as the ratio between the systolic blood pressure in the right or left toe and the higher systolic pressure in the right or left UPPER arms.  
Impressum
Assessment of vital signs – Blood pressure

Authors: Veronika Rajki, PhD, Pál Bakó
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Reference number: 630033

Mozaik Education, 2024
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