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Reference values for respiratory rate in the first 3 years of life
F Rusconi1, M Castagneto, L Gagliardi
1First Department of Pediatrics, University of Milano, Italy.
Insights
This study established normal respiratory rate ranges for infants and young children using percentile curves. Stethoscope measurements showed good repeatability and were slightly higher than observational counts, aiding in diagnosing childhood respiratory infections.
Area of Science:
- Pediatric Medicine
- Respiratory Physiology
- Diagnostic Tools
Background:
- Elevated respiratory rate is a key indicator for diagnosing lower respiratory infections in children.
- Establishing normal respiratory rate ranges in large pediatric populations is crucial but lacking.
Purpose of the Study:
- To define normal respiratory rate ranges in infants and young children by creating age-specific percentile curves.
- To assess the reliability of respiratory rate measurements using a stethoscope and compare it with observational methods.
Main Methods:
- Respiratory rate was measured for 1 minute using a stethoscope in 618 healthy children aged 15 days to 3 years, both awake and asleep.
- Repeatability was tested by re-measuring 30-60 minutes apart in 50 subjects.
- Stethoscope counts were compared with simultaneous observational counts in another 50 subjects.
Main Results:
- Stethoscope measurements demonstrated good repeatability (SD 1.7-2.5 breaths/minute).
- Stethoscope counts were consistently higher than observational counts (mean difference 1.8-2.6 breaths/minute).
- Respiratory rate decreased with age, particularly rapidly in early infancy, with greater value dispersion observed during this period.
Conclusions:
- Respiratory rate measurement with a stethoscope is a repeatable and reliable method.
- Developed percentile curves are valuable for diagnosing respiratory conditions, especially in early infancy where rapid rate changes occur.
- These curves help define "normality" when standard cut-off values are insufficient.
Background:
Raised respiratory rate is a useful sign to diagnose lower respiratory infections in childhood. However, the normal range for respiratory rate has not been defined in a proper, large sample.
Objective:
To assess the respiratory rate in a large number of infants and young children in order to construct percentile curves by age; to determine the repeatability to the assessment using a stethoscope and compare it with observation.
Methods:
Respiratory rate was recorded for 1 minute with a stethoscope in 618 infants and children, aged 15 days to 3 years old, without respiratory infections or any other severe disease when awake and calm and when asleep. In 50 subjects we compared respiratory rate taken 30 to 60 minutes apart to assess repeatability, and in 50 others we compared simultaneous counts obtained by stethoscope versus observation.
Results:
Repeatability was good as the standard deviation of differences was 2.5 breaths/minute in awake and 1.7 breaths/minute in asleep children. Respiratory rate obtained with a stethoscope was systematically higher than that obtained by observation (mean difference 2.6 breaths/minute in awake and 1.8 breaths/minute in asleep children; P = .015 and P < .001, respectively). A decrease in respiratory rate with age was seen for both states, and it was faster in the first few months of life when also a greater dispersion of values was observed. A second degree polynomial curve accurately fitted the data. Reference percentile values were developed from these data.
Conclusions:
The repeatability of respiratory rate measured with a stethoscope was good. Percentile curves would be particularly helpful in the first months of life when the decline in respiratory rate is very rapid and prevents to use cut off values for defining "normality."