Pediatric Vital Signs Reference Chart
Blood Pressure
For blood pressure assessment in children, use age-, sex-, and height-specific percentiles as defined by the American Academy of Pediatrics, with normal BP defined as below the 90th percentile, elevated BP as ≥90th but <95th percentile, and hypertension as ≥95th percentile. 1, 2
Key BP Values by Age:
- 6-year-old girl (50th height percentile): Systolic BP 50th percentile = 105 mmHg (95th = 111 mmHg); Diastolic BP 50th percentile = 67 mmHg (95th = 74 mmHg) 1
- Children 1-10 years: Hypotension defined as systolic BP <70 mmHg + (2 × age in years) 2
- Critical measurement requirements: Proper cuff sizing is essential—bladder width must be 40% of mid-arm circumference and cover 80-100% of arm circumference 1
- Measurement technique: Child must be seated quietly with right arm resting at heart level on solid surface 1
Clinical Application:
- Any systolic BP ≥90th percentile or diastolic ≥90th percentile warrants further evaluation 1, 2
- Confirm diagnosis on three separate days before labeling as hypertension 2
- Consider ambulatory BP monitoring to rule out white coat hypertension 1
Heart Rate
Heart rate in children shows age-dependent variation with median values declining from infancy through adolescence, peaking at approximately 145 bpm at 1 month of age before gradually decreasing. 3
Normal Heart Rate Ranges by Age:
- Birth: Median 127 bpm 3
- 1 month: Peak median 145 bpm 3
- 2 years: Median 113 bpm 3
- 3 years: Range 80-120 bpm 2
- Adolescents/athletes: Heart rates as low as 30-60 bpm can be normal due to increased vagal tone 4
Clinical Interpretation:
- Bradycardia in young athletes (HR <60 bpm) is a normal physiological adaptation and requires no intervention if asymptomatic 4
- Concern warranted only when HR <30 bpm, sinus pauses ≥3 seconds, or symptoms present (syncope, weakness, dyspnea) 4
- Tachycardia may indicate fever, infection, anemia, pain, or dehydration 2
- Do not misinterpret transient changes during feeding, sleep, or defecation as pathological 2
Evidence-Based Centiles:
- Recent large-scale studies (143,346 children) demonstrate that current PALS guidelines frequently exceed the 99th centile or cross the median, indicating they do not reflect actual pediatric populations 3, 5
Respiratory Rate
Respiratory rate shows the steepest decline in infants under 2 years, decreasing from a median of 44 breaths/min at birth to 26 breaths/min at 2 years, then continuing gradual decline through adolescence. 3
Normal Respiratory Rate Ranges by Age:
- Birth: Median 44 breaths/min 3
- 2 years: Median 26 breaths/min 3
- Early adolescence: Continued gradual decline 3, 6
Clinical Application:
- Age-specific centile charts derived from 1.4 million emergency department visits show substantial discrepancies with PALS guidelines 6
- Use evidence-based centile charts rather than dichotomizing into "normal" versus "abnormal"—assess degree of deviation from age-specific median 5
- Respiratory rate assessment is critical for detecting respiratory distress, shock, and metabolic abnormalities 7
Important Clinical Pitfalls
Measurement Accuracy:
- Blood pressure is the most inconsistently obtained vital sign, especially in younger children 8
- Incorrect cuff size leads to falsely elevated or decreased readings 1
- Patient anxiety, recent activity, and measurement technique significantly affect values 7
Interpretation Errors:
- Isolated measurements should not drive clinical decisions—clinical context and overall condition are paramount 2
- Current PALS thresholds do not reflect observed vital signs in real-world pediatric populations 3, 5
- Single abnormal values require confirmation before diagnosis, particularly for hypertension 2