B02 Blood Pressure Monitoring Introduction NOTTINGHAM CHILDREN S HOSPITAL Nursing Guideline Children should have their blood pressure checked at least once during every episode when they come into contact with health care settings (The National High Blood Pressure Education Program working group 2004). Abnormal blood pressure can be indicative of a number of health problems. There are a number of basic principles that should be adhered to regardless of method used to measure. Action Whenever possible the child should be rested for 3 minutes before each measurement. Ensure the child is comfortable, with the limb used for measurement resting at heart level. The bladder in the cuff used should encircle 80-100% of the limb circumference (this is often indicated by a range guide on the cuff itself). The widest cuff available should be used. A selection of cuffs must be available. When possible the same limb, cuff and method of measurement should be used each time. Therefore it is important for this information to be clearly documented. Always leave at least one minute between each reading. Rationale Activity elevates heart rate, and blood pressure and will lead to inaccurate reading. If the child is uncomfortable it can increase heart rate and blood pressure, and will lead to an inaccurate reading (O Brien et al 2003). A cuff that is too small will give a false high reading, and a cuff that is too large will give a false low (O Brien et al 2003). For blood pressure readings to be comparable with each other the same method and equipment is needed. This enables the child to settle and become calm, to promote the accuracy of the reading (O Brien et al 2003). Recording blood pressure measurement BP = SYSTOLIC for example: 120 DIASTOLIC 80 mmhg Readings should be recorded accurately to 2mmHg, not rounded to the nearest value. B02 Page 1 of 8
On a chart the blood pressure is expressed in a straight line from systolic to diastolic reading. 120 110 100 90 80 70 60 Normal Blood pressure readings for children Children s blood pressure increases with size. The most accurate way of measuring blood pressure is comparing readings based upon the child s height, using the normal growth charts to determine the child s percentile. See tables below for information (Source: The National High Blood Pressure Education Program working group 2004). A child would be considered to be normotensive if their blood pressure is at the 90 th percentile or less. B02 Page 2 of 8
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1. Measurement of blood pressure using a manual Sphygmomanometer In very young children it can be difficult to hear accurate Korotkoff sounds using a stethoscope, and a Doppler device may need to be used (O Brien et al 1997). This device amplifies the pulse, but only allows a systolic reading to be recorded. If a stethoscope is used the bell, rather than the diaphragm, amplifies the sound more effectively. However the diaphragm covers a larger surface area. Korotkoff sounds Phase I Appearance of clear tapping sounds. SYSTOLIC PRESSURE Phase II Softening of sounds Auscultatory gap In some patient sounds disappear for a short time. Phase III Return of sharper sounds Phase IV Muffling of sounds Phase V Sounds disappear. DIASTOLIC PRESSURE (O Brien et al 2003 Valler-Jones and Wedgbury 2005) In a very small number of people the phase 5 is not heard and phase 4 should then be used as the diastolic reading. In this situation this should be clearly documented. Standard Statement A registered nurse will obtain an accurate measurement of a child s blood pressure (Renal Clinical Support Workers on E17 who have received additional training may also undertake this task once deemed competent) Equipment Stethoscope, or Doppler device (ultrasound gel will be needed). Manual sphygmomanometer Appropriate cuff B02 Page 5 of 8
Process Action 1. Place the appropriate cuff on the child s limb, ensuring the artery indicator is placed over the artery to be used for the measurement. The right arm should be used whenever possible. However if this limb is injured or has a cannula in situ it should not be used. 2. Attach tubing to sphygmomanometer, ensuring equipment is in a good state of repair (tubing intact and checked in the last year by Medical Physics). 3. Place stethoscope on artery, or turn on Doppler device apply gel to probe and place on artery. 4. Close valve on tubing and inflate cuff by compressing the bulb, to 30mmHg above the estimated systolic pressure. NB An estimate of systolic pressure can be obtained by palpating the pulse whilst inflating the cuff, and determined by the disappearance of the pulse beat. 5. Release pressure by opening valve, at 2-3mmHg a second, listening for the appropriate Korotkoff sounds identified above. 6. As soon as the diastolic pressure is heard (systolic if using a Doppler) the pressure should be totally released, and the cuff removed. 7. Record reading to the nearest 2mmHg, do not round off. Record any other significant information Rationale To ensure an accurate reading is obtained (The National High Blood Pressure Education Program working group 2004). To enable the Korotkoff sounds to be heard. Phase III can be confused as the systolic pressure, if the cuff is not inflated high enough. If the cuff is deflated too quickly it will be difficult to identify an accurate reading. This ensures the child is as comfortable as possible during the procedure. Rounding off to the nearest 5-10mmHg can result in an inaccurate reading being recorded. This can B02 Page 6 of 8
as indicated above. 8. Compare reading to expected levels, and report any abnormalities. affect decisions made about treatment (O Brien et al 2003). 2. Measurement blood pressure using an automated monitor. Automated monitors (e.g. Datascope, Dinamap, GE Solar) are methods of non-invasive blood pressure monitoring. It is important that the model used is approved for the use in children (O Brien et al 2001). Single readings can be obtained, or timing functions can be used to repeat readings on most models. If this function is used blood pressure cuffs should be changed every four hours. Equipment Blood pressure Monitor Appropriate cuff Process Action 1. Place the appropriate cuff on the child s limb, ensuring artery indicator is placed over the artery to be used for the measurement. The right arm should be used whenever possible. However if this limb is injured or has a cannula in situ it should not be used. 2. Connect cuff leads to machine. 3. Switch on machine, and if possible set for 30mmHg above expected systolic pressure. This can be changed on many models. 4. Press the machine to start, ensuring child comfortable and limb supported. Rationale To ensure an accurate reading is obtained (The National High Blood Pressure Education Program working group 2004). This will increase the accuracy of the reading, enabling the machine to detect the oscillations in pressure accurately (Datascope Corp 2000). 5. Remove cuff. To make child comfortable. 6. Record reading to the nearest 2mmHg, this should not be Rounding off to the nearest 5-10mmHg can result in an inaccurate B02 Page 7 of 8
rounded off. Record any other significant information as indicated below. 7. Compare reading to expected levels, and report any abnormalities. reading being recorded. This can affect decisions made about treatment (O Brien et al 2003). Outcome The child will have an accurate measurement of their blood pressure. The child s notes will have an accurate record of the reading taken, and abnormal readings reported to a more senior member of the team. References Datascope Corp. (2000) Accutorr Plus Operating Instructions. National High Blood Pressure Education Program Working Group on High Blood pressure in Children and Adolescents (2004) The Fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 114 pp555-576 O Brien, E.T. Petrie, J.C. Littler, W.A. de Swiet, M. Padfield, P.D. Cillon, M.J. Coats, A. and Mee, F. (1997) Blood pressure measurement. Recommendations of the British Hypertension Society. Third Edition. BMJ Publishing Group, London O Brien, E. Waeber, B. Parati, G. Staessen, J. and Myers, G. (2001) Blood pressure measuring devices: recommendations of the European Society of Hypertension. British Medical Journal 322: 531-536 O Brien, E. Asmar, R. Beilin, L. Imai, Y. Mallion, J, Mancia, G. Mengden, T. Myers, M. Padfield, P. Palatini, P. Parati, G. Pickering, T. Redon, J. Staesson, J. Stergiou, G. and Verdecchia, P. (2003) European Society of Hypertension recommendations for conventional, ambulatory and home blood pressure measurement. Journal of Hypertension. 21: 821-848 Valler-Jones, T. and Wedgbury, K. (2005) Measuring Blood pressure using the mercury sphygmomanometer. British Journal of Nursing 14 (3)145-150 Author: Diane Blyton Date: 2010 Reviewed: August 2015 no changes made Review date: August 2020 B02 Page 8 of 8