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A method for normalization of oxygen cost and consumption in normal children while walking
T R Bowen1, S R Cooley, P W Castagno
1Department of Orthopaedics, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19899, USA.
Insights
This study establishes valid telemetric measurements for oxygen use in nondisabled children, providing equations to assess energy expenditure and identify walking abnormalities.
Area of Science:
- Pediatric Exercise Physiology
- Biomechanical Analysis
- Clinical Measurement
Background:
- Accurate measurement of oxygen use is crucial for assessing energy expenditure in children, particularly those with walking abnormalities.
- Existing telemetric systems lack statistically validated reference data for oxygen consumption in healthy, nondisabled children.
- Establishing normative data is essential for comparing energy expenditure in children with gait impairments to their peers.
Purpose of the Study:
- To establish statistically valid telemetric measurements of oxygen cost and oxygen consumption in nondisabled children.
- To develop predictive equations for oxygen cost and consumption based on body surface area.
- To create indices for quantifying variations in energy use among children.
Main Methods:
- Collected data from 94 nondisabled children (ages 5-15 years) using the Cosmed K2 oxygen analysis system.
- Measured oxygen cost (mL O2/kg/m) and oxygen consumption (mL O2/kg/min).
- Correlated these measurements with inverse body surface area (IBSA) to derive linear regression equations.
Main Results:
- Developed predictive equations: oxygen cost = 0.256 (IBSA) + 0.052 (r=0.806) and oxygen consumption = 17.635 (IBSA) + 4.956 (r=0.758).
- Established indices to quantify deviations from predicted normal energy expenditure.
- Demonstrated the utility of these indices for comparing energy use across different measurements and over time.
Conclusions:
- The derived equations and indices provide a reliable method for quantifying energy expenditure in children.
- These tools enable objective comparison of energy use in children with walking abnormalities against normative data.
- The developed indices facilitate longitudinal tracking of energy expenditure, accounting for changes in anthropometric variables.
Abstract:
Measurement of oxygen use is helpful in determining energy consumption in children with walking abnormalities; however, no statistically valid measurements of nondisabled children have been established using a telemetric system. Data from 94 nondisabled children, ages 5-15 years, were collected using the Cosmed K2 oxygen analysis system. Oxygen cost, measured in milliliters O2/kg/m walked, and oxygen consumption, measured in milliliters O2/kg/min, were correlated to inverse body surface area (IBSA) measured in meters(-2). Linear relationships between oxygen cost and IBSA and between oxygen consumption and IBSA were best described by the following equations: oxygen cost = 0.256 (IBSA) + 0.052 (r = 0.806) and oxygen consumption = 17.635 (IBSA) + 4.956 (r = 0.758). From these data, equations were derived to calculate predicted oxygen cost and predicted oxygen consumption for each child. Indices were developed to express the difference between a measurement and the predicted mean in reference to the normal variation. These equations and indices can help quantify the variation of energy use of children with walking abnormalities when compared with their nondisabled peers. Additionally, the indices enable multiple tests from one subject to be compared, regardless of a change in age, height, and weight between measurements.