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Blood pressure monitoring in infants, children, and young people

Key messages

  • Users should be aware that for infants, young children, and young adults experiencing abnormal heart rhythms, weak pulse, very low or very high blood pressure (BP), muscle tremors, or any movement during the BP measurement with automated devices may fail to obtain a reading and will either indicate an error code or give unreliable results
  • Incorrect cuff size is a major source of error for both automated BP measuring devices and manual sphygmomanometers/doppler. An under-sized cuff can significantly over-estimate BP
  • Incorrect cuff placement can also be a major source of error, this is particularly important in infants and young children. The cuff should be placed on the arm with the centre of the bladder over the brachial artery. A cuff that encircles close to 100% of the upper arm circumference will reduce the risk of cuff error significantly

Measurement

How to measure systolic BP using a doppler and greenlight 300TM sphygmomanometer

  • Ensure the child is comfortable
  • Apply the cuff, ensure the internal bladder encircles 90–100% of the upper arm circumference
  • The arrow on the cuff should be placed over the brachial artery
  • The first BP reading should be estimated by placing a doppler over the pulse and pumping up the cuff. When the pulse sound disappears this is your estimated BP. Now deflate the cuff quickly
  • Keep the doppler over the pulse; pump the cuff up to a pressure 30 mmHg higher than the estimated BP
  • Reduce the pressure slowly (you should see a green light on the right-hand side of the monitor; this indicates that the pressure is reduced at the correct speed)
  • The first repetitive sound is recorded as the systolic BP
  • If you need to repeat the BP you should wait 1 minute to give the vessels a chance to refill
  • Record the systolic BP measurement immediately on Nervecentre/CareVue/children’s early warning score (CEWS) chart as appropriate
  • To obtain a diastolic reading use a stethoscope rather than doppler
  • For instructions on how to measure BP with a stethoscope, please refer to auscultation section below

Preparation

  • The equipment required should be gathered and checked prior to performing the BP measurement. This should be cleaned according to policy in place

Sphygmomanometer

  • Light or dial:
    • on zero
    • not obscured
  • Maintenance/recalibration:
    • they should be serviced yearly by biomedical engineering department to confirm accuracy
    • date of last calibration should be clearly stated on the manometer
  • Cuff bladder:
    • bladder, tubing, connections, inflation bulb, and valves are sound
    • nylon cuffs should be wiped with disinfectant wipes between patients
    • fabric cuffs should be washed regularly
    • disposable or single patient use cuff should be used for children who are considered infectious or immunocompromised
  • Cuff sheath:
    • good condition
    • secure fastening
    • clean
    • correct size

Equipment for manual measurement

  • Inflation/deflation device:
    • control valves, leaks, vents, tubing—should be clean and not perished
    • the system must be able to inflate rapidly
    • deflation should be smooth and able to be reduced at 2 mmHg/second
  • Stethoscope:
    • good condition, with clean well-fitting earpieces
  • Doppler probe:
    • clean (using water not alcohol)
    • used according to manufacturer’s guidelines
  • Automated blood pressure monitor:
    • refer to manufacturer’s guidelines
    • choose cuff size according to guidelines below not according to the label on the cuff (infant, small child)

Choosing the correct cuff size

  • The inflatable part of the cuff (bladder) should cover a minimum of 90% and preferably 100% of the circumference of the arm. The width of the bladder should ideally be the full length from under the arm (axilla) to the olecranon (elbow) or the largest cuff that can fit onto the upper arm and still allow auscillation of the brachial artery. If these criteria cannot both be met, the largest cuff available for the arm should be used

Undertaking the procedure

  • Wash hands before carrying out the procedure
  • Explain procedure to child/young person:
    • warn of minor discomfort that may be caused
    • explain that the procedure may be repeated
  • The child/young person should ideally be asked to sit quietly for 3–5 minutes and wait 30 minutes after having eaten or exercised

Automated measurement of blood pressure

  • As few monitors have been validated for use in paediatrics and those that have are not validated for children with high BP, they cannot be recommended for use in younger children with high BP. A manual BP should be measured

Position the manometer

  • It should be:
    • vertical or on a tilt if wall mounted
    • at eye level more than 1 metre from the observer
    • the observer should be comfortably positioned in order to be able to inflate and deflate the cuff gradually with ease
  • Posture of patient:
    • the child/young person should be in a seated position
    • the child/young person should be resting for 3 minutes before performing BP
    • the legs should be uncrossed

Taking a blood pressure

  • Ensure the area is child friendly and that they are comfortable in the environment
  • Tight or restrictive clothing should be removed from the arm/leg
  • Apply the cuff and ensure the centre of the bladder marked with an arrow is placed over the brachial artery. This should fit firmly and be well secured. The lower edge of the bladder should be 1 centimetre above the tubing from the BP cuff and should not cross the auscultatory area. The exception to this would be children who need long cuffs for large arm circumference. If the cuff covers the brachial area the radial pulse should be used
  • The tubing may lie inferior (going down), superior (going up), or posterior (at the back)
  • The arm should be well supported at the level of mid-sternum

Auscultation only

  • The first BP reading should be estimated by palpation/doppler
  • Place the stethoscope/doppler/fingers over the pulse. Do not press too firmly or touch the cuff
  • Inflate the cuff over 3–5 seconds. When the pulse sound disappears this is your estimated BP. Now deflate the cuff quickly
  • Place the doppler/stethoscope just above the antecubital fossa where you will hear the maximal pulsation of the brachial artery in the arm
  • Inflate the bladder once again steadily to a pressure of 30 mmHg above the previously estimated systolic BP
  • Reduce the pressure at 2 mmHg per second. If you are using the greenlight 300TM a green light appears on the bottom right hand side of the monitor indicating deflation speed is correct
  • The point at which the first repetitive, clear tapping sounds (phase 1) first appear for at least two consecutive beats gives the systolic BP
  • The point at which the repetitive sounds disappear (phase 5) gives the diastolic BP. Note: a doppler will not record the diastolic BP. If a diastolic BP is required, a stethoscope is required
  • Then continue to completely deflate the cuff rapidly
  • All measurements should be taken to the nearest 2 mmHg. A diastolic BP phase 5 may not be present in some groups of children. For these children, the diastolic BP should be recorded at the point where muffling of the repetitive sounds is taken (phase 4). This should be clearly documented as phase 4
  • There may be a ‘silent’ or ‘auscultatory gap’ where sounds disappear shortly after the systolic phase is heard. This should be documented if it is noted—care must be taken to ensure that the systolic phase is heard and the return of the sounds after the gap are not thought to be the systolic BP
  • If the reading is difficult to ascertain—which is common in small, unsettled infants—it may be easier to find a second person to assist with the measurement
  • If it is necessary to repeat the BP measurement, the cuff should be allowed to fully deflate, and 1 minute should elapse before the next measurement is taken

Recording a blood pressure

  • The arm in which the pressure is being recorded and the position of the subject should be noted, for example, left arm–sitting
  • The arm used, cuff size, and method of measurement should be indicated
  • If the child/young person is anxious, restless, or distressed, a note should be made with the BP

full guideline from…

www.gosh.nhs.uk/health-professionals/clinical-guidelines/blood-pressure-monitoring 

Great Ormond Street Hospital. Blood pressure monitoring. October 2015.