Vital Signs: Blood Pressure

CLINICAL GUIDELINES

A registered nurse (RN), licensed practical nurse (LPN), or unlicensed assistive personnel (UAP) may measure blood pressure (BP). When the BP is taken by the UAP, any variance from previous measures is reported to the licensed caregiver.
BP is measured initially to obtain baseline data to assess general hemodynamic status of each child within the first hour of admission to an acute care setting.
BP is measured to assess response to treatment regimes.

A decrease in BP is a late sign of shock in children.

During acute illness, measure BP every 4 to 8 hours or more frequently as clinically indicated.
In neonates, measure BP if renal disease or coarctation of the aorta is suspected or if clinical signs of hypotension are present. Universal screening of neonates is not recommended. Wide variability exists in BP between limbs. Suspicion of coarctation must be followed up with echocardiography.
Do not routinely measure BP in children with osteogenesis imperfecta due to high risk of fractures; measure BP only with a direct order from healthcare prescriber.
For health maintenance, BP should be measured:
- When a child older than 3 years of age is seen in a healthcare setting
- In a child younger than 3 years of age with history of neonatal condition requiring intensive care; symptoms of hypertension, hypotension, elevated intracranial pressure, recurrent urinary tract infections, and renal or cardiac disease; malignancy or transplant (solid organ, bone marrow); and treatment with medications known to affect BP
Auscultation is the preferred method of measuring BP in children because frequent calibration of automated devices is required and there is a lack of established reference standards for children. Automated devices are acceptable when auscultation is difficult (e.g., in young children) or when frequent measurements are required.
Use the right arm whenever possible for consistency of measurement and comparison with standard norms.

CHILD AND FAMILY ASSESSMENT AND PREPARATION

Assess for signs of hypotension, including weak pulse, diaphoresis, pallor, and dizziness.
Assess for signs of hypertension, including headache, bounding pulse, and flushing.
Explain to the child and family why monitoring is important, how it is done, and equipment used. Use language that is appropriate for developmental level (e.g., “I’m going to see how your heart is working. You will feel like your arm is getting a hug.”).
In nonemergent situations:
- Show child equipment and let child handle equipment.
- Demonstrate on family member, other staff, or stuffed animal how procedure is done and how equipment is used, as age appropriate.
Measure BP after 5 minutes of rest, when possible, to ensure the most accurate reading because agitation may falsely elevate the results. Position child’s arm (extremity) at heart level during the rest; a level below the heart may cause false high readings, a level above the heart may cause false low readings.

PROCEDURE
Auscultation Method

Steps	Rationale/Points of Emphasis
1 Review child’s previous BP readings.	Provides baseline data for comparison, if available.
2 Analyze child’s diagnosis and current medications for effect on BP.	Alerts to possible problems and drugs that may affect the BP.
3 Perform hand hygiene. Cleanse stethoscope chest piece with antiseptic wipe before and after examination.	Reduces transmission of microorganisms.
4a Select site (Figure 119-1). Begin by checking record to see whether previous measurement was taken. If so, use same site and position. Use right arm when possible.	Extremity closest to the heart provides consistency and comparability with standard norms and child’s own readings. KidKare Although the right arm is preferable, child’s anxiety, anatomy, or condition may necessitate using another extremity.
4b Do not use extremity that has an injury, wound, or foreign devices (e.g., IV, arteriovenous, or renal dialysis shunt).	May cause further injury or potentiate thrombi in indwelling devices.
4c Do not use extremity with altered circulation (e.g., Blalock-Taussig shunt, coarctation).	Measurement may be inaccurate and further compromise an already compromised extremity.
Figure 119-1 Arterial sites used to measure BP: brachial, radial, popliteal, posterior tibial, and dorsalis pedis.
5a Select appropriately sized cuff (Figure 119-2). Figure 119-2 Determination of proper cuff size: identify midpoint between the olecranon (elbow) and the acromion (shoulder).	Facilitates correct cuff selection to obtain accurate measurement. The practice of labeling of BP cuffs as “infant,” “pediatric,” “small adult,” “adult,” and “large adult” is misleading, and such designation may result in the improper choice of equipment. Using upper arm circumference (UAC) as a measure for cuff size most closely reflects directly measured radial arterial pressure but significantly overestimates diastolic pressure. When two-thirds or three-fourths of the upper arm length are used as cuff selection criterion, they significantly underestimate systolic and diastolic BP compared with directly measured radial arterial pressure.
5b Bladder width should be about 40% of the arm circumference midway between the olecranon (elbow) and the acromion (shoulder).	Increases accuracy of measurement. Using too small a cuff may falsely elevate measurement; too large a cuff may give falsely low reading.
5c This usually corresponds to a cuff bladder that covers 80-100% of the arm circumference.	Use the manufacturer’s lines on the cuff as a guide for cuff selection.
5d If unable to obtain the appropriately sized cuff, choose one that is oversized rather than too small.	Too large a size tends to have less effect than too small.
6 Center the bladder of the cuff on the extremity proximal to the pulse (e.g., at the brachial site, position about 1-2 in above the antecubital fossa) and snugly secure cuff.	A loose cuff may give a false high reading.
7 Locate the pulse at the site. Place the bell of the stethoscope where the pulse is felt, below the bottom edge of the cuff.	Facilitates hearing Korotkoff sounds that are of low frequency, which the bell is best for auscultating.
8 Close sphygmomanometer valve, and inflate cuff to a pressure 30 mm Hg above the point at which artery pulsation is obliterated. Stabilize extremity during measurement.	Inflation higher than point of pulse obliteration avoids missing auscultation of first sound. Movement may cause extra sounds and interfere with ability to hear pulsations.
9 Deflate cuff at a rate of 2-3 mm Hg per second.	Ensures accurate measurement of BP.
10a Note Korotkoff sounds, beginning with the onset of tapping sound.	Correlates with phase I, which represents systolic pressure.
10b Note muffling of the sound, if applicable.	Muffling of the sound represents phase IV. This may occur several millimeters before disappearance of the sound. This occurs more commonly in preadolescents. The presence of diastolic hypertension can be excluded when Korotkoff sounds are heard to 0 mm Hg.
10c Note disappearance of sound.	Silence correlates with phase V, which corresponds with diastolic pressure.
11 Do not reinflate cuff during deflation. If necessary to repeat BP, allow a few minutes between measurements.	Ensures more accurate measurement.
12 Completely deflate cuff and remove from arm.	Measurement is complete.
13 Return equipment to safe storage location. Perform hand hygiene.	Reduces transmission of microorganisms.