From the Guidelines
The normal vital signs for a 1-year-old infant are as follows: Heart rate: 100-190 beats per minute, Respiratory rate: below 60 per minute, Blood pressure: Systolic 72-104 mmHg, Diastolic 37-56 mmHg, and Temperature: 36.5°C to 37.4°C (97.7–99.3°F). These ranges are based on the most recent and highest quality study available, which provides guidelines for the assessment of vital signs in infants 1. It's essential to note that these ranges are guidelines, and an infant's vital signs should be interpreted in the context of their overall health and behavior. Factors such as activity level, feeding, and sleep state can influence these values. When assessing an infant's vital signs, it's crucial to use age-appropriate equipment and techniques. For example, blood pressure should be measured using an appropriately sized cuff, and temperature is most accurately taken axillary in this age group, as recommended by the American Academy of Pediatrics 1. Any significant deviation from these ranges, especially if persistent or accompanied by other symptoms, should prompt further medical evaluation. The provided evidence from 1 includes tables that outline normal heart rate and blood pressure ranges by age, which support the recommended vital sign ranges for a 1-year-old infant. Additionally, the evidence from 1 emphasizes the importance of documenting vital signs within normal ranges before discharge from the hospital, highlighting the significance of monitoring these values in infants. In contrast, the evidence from 1 focuses on guidelines for monitoring and management of pediatric patients during and after sedation, which is not directly relevant to the assessment of normal vital signs in a 1-year-old infant. Therefore, the recommendation is based on the most relevant and recent evidence available 1.
From the Research
Normal Vital Signs for a 1-Year-Old Infant
The normal vital signs for a 1-year-old infant can be summarized as follows:
- Heart rate:
- Median heart rate is around 113 beats per min at 2 years of age, with a decline from a median of 127 beats per min at birth to 113 beats per min by 2 years of age 2
- The 50th percentile for heart rate in infants is around 120-122 bpm, with the 2nd and 98th percentiles being around 96-100 bpm and 150-156 bpm, respectively 3
- Respiratory rate:
- Median respiratory rate declines from 44 breaths per min at birth to 26 breaths per min at 2 years of age, with the steepest fall apparent in infants under 2 years of age 2
- There is no specific data available for a 1-year-old infant, but the decline in respiratory rate from birth to early adolescence is well-documented 2
- Blood pressure and other vital signs:
- There is limited data available on blood pressure for a 1-year-old infant, but age-specific centile curves for blood pressure, heart rate, and respiratory rate have been developed for pediatric patients 4
- Outcome-driven vital signs ranges for children in the prehospital setting have been established, including data-driven thresholds for abnormal vital signs 5
Age-Specific Centile Curves
Age-specific centile curves have been developed for pediatric patients, including:
- Blood pressure: comprehensive age-specific centile curves for systolic, diastolic, and mean blood pressure 4
- Heart rate: centile curves show a decline in heart rate from birth to early adolescence, with a small peak at age 1 month 2
- Respiratory rate: centile curves show a decline in respiratory rate from birth to early adolescence, with the steepest fall apparent in infants under 2 years of age 2
Clinical Applications
These centile curves and vital sign ranges can be used in clinical practice to: