What is the recommended approach for assessing and managing elevated blood pressure in pediatric patients using blood pressure (BP) centile charts?

Blood Pressure Centile Charts in Pediatrics

Use the 2017 AAP sex-, age-, and height-specific BP percentile tables for children <13 years, and apply the simplified adult thresholds (120/80 mmHg for elevated BP, 130/80 mmHg for hypertension) for adolescents ≥13 years. 1

BP Classification Framework

For Children <13 Years of Age

• Normal BP: <90th percentile for age, sex, and height 1
• Elevated BP: ≥90th to <95th percentile for age, sex, and height 1
• Stage 1 Hypertension: ≥95th percentile for age, sex, and height 1
• Stage 2 Hypertension: ≥95th percentile + 12 mm Hg 1

For Adolescents ≥13 Years of Age

The 2017 AAP guidelines align with adult definitions to simplify management: 1

• Normal BP: <120/<80 mm Hg 1
• Elevated BP: 120-129/<80 mm Hg 1
• Stage 1 Hypertension: 130/80 to 139/89 mm Hg 1
• Stage 2 Hypertension: ≥140/90 mm Hg 1

This change was made because the 95th percentile for adolescents ≥13 years approximates 130 mm Hg systolic, allowing alignment with adult cardiovascular prevention guidelines. 1

Key Updates in the 2017 AAP Tables

The new normative BP values are based exclusively on normal-weight children (BMI <85th percentile), resulting in values 2-3 mm Hg lower than previous tables that included overweight/obese children. 1 This addresses the confounding effect of obesity on BP norms and provides more accurate thresholds for identifying true hypertension. 2

The tables provide BP values at the 50th, 90th, 95th percentiles, and 95th percentile + 12 mm Hg, stratified by sex, age (1-17 years), and height percentile. 1

Simplified Screening Table

For initial screening, use the simplified table listing 90th percentile BP values for children at the 5th percentile of height—this has a negative predictive value >99%. 1 This screening tool identifies children needing further evaluation but should never be used alone for diagnosis. 1

If the screening table suggests elevated BP, you must confirm using the complete sex-, age-, and height-specific tables, as actual cutoffs may be up to 9 mm Hg higher depending on the child's height percentile. 1

Proper Measurement Technique

Essential Requirements

• Auscultation remains the gold standard for diagnosis (oscillometric devices are acceptable for screening but must be validated for pediatric use). 1, 3
• Measure BP in the right arm to ensure consistency with normative data and detect coarctation of the aorta. 3
• Correct cuff sizing is critical: bladder width should be 40% of mid-arm circumference, covering 80-100% of arm circumference. 4 Undercuffing (too small) falsely elevates readings; overcuffing (too large) falsely lowers them, though the error is smaller with overcuffing. 3
• Patient must be seated quietly for 3-5 minutes with back supported, feet flat on floor, and arm at heart level. 4, 5

Common Pitfalls

Studies show that while BP is measured in 97% of well-child visits, 60% of elevated readings receive no intervention, often due to high daily patient loads and failure to recognize abnormal values. 6 The complexity of the full BP tables contributes to under-recognition of pediatric hypertension. 1, 6

Diagnostic Confirmation

Hypertension diagnosis requires elevated BP at 3 separate visits unless the patient is symptomatic. 1 This accounts for the high variability in pediatric BP—only 56% of adolescents maintain the same hypertension stage across 3 occasions. 1

Role of Ambulatory BP Monitoring (ABPM)

ABPM should be performed routinely to confirm hypertension before initiating treatment, given the high prevalence of white coat hypertension in children (up to 50%). 1 This is cost-effective as it prevents unnecessary diagnostic workup and treatment in children with white coat hypertension. 1

ABPM is specifically indicated for: 1

• Confirming diagnosis in children with repeatedly elevated office BP
• Ruling out white coat hypertension (defined as office BP ≥95th percentile but mean ambulatory BP <95th percentile with BP load <25%)
• Detecting masked hypertension in high-risk patients (repaired coarctation, chronic kidney disease, transplant recipients)
• Evaluating treatment effectiveness
• Assessing for non-dipping patterns in patients with obstructive sleep apnea, prematurity, or genetic syndromes

The AAP found insufficient evidence to support home BP monitoring for diagnosis in children, though it may be used when ABPM is unavailable. 1, 4 Wrist and finger monitors should never be used. 4

Screening Recommendations

Perform routine BP screening annually at preventive care visits starting at age 3 years. 1 More frequent screening is warranted for children with obesity, diabetes, heart disease, or kidney disease. 1, 4

This represents a change from prior guidelines that recommended BP measurement at every healthcare encounter—the 2017 AAP guideline acknowledges screening controversies while maintaining annual screening to detect secondary hypertension. 1

Practical Application Algorithm

1. Initial screening: Use simplified 90th percentile table or measure BP with validated device 1
2. If elevated: Remeasure at same visit after 5 minutes rest; confirm with auscultation 1, 5
3. If still elevated: Compare to full sex-, age-, height-specific tables to classify as normal, elevated BP, or hypertension 1
4. If elevated BP or hypertension: Repeat measurements at 2 additional visits 1
5. If persistently elevated: Obtain ABPM to confirm diagnosis and exclude white coat hypertension 1
6. For adolescents ≥13 years: Apply simplified thresholds (120/80,130/80,140/90 mm Hg) rather than percentile tables 1