使用n-of-1方法学对间接热量计进行验证。

Validation of an indirect calorimeter using n-of-1 methodology.

作者信息

Frankenfield David C, Ashcraft Christine M, Wood Carola, Chinchilli Vernon M

机构信息

Department of Clinical Nutrition, Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033, United States; Department of Nursing, Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033, United States.

出版信息

Clin Nutr. 2016 Feb;35(1):163-168. doi: 10.1016/j.clnu.2015.01.017. Epub 2015 Feb 2.

DOI:10.1016/j.clnu.2015.01.017

PMID:25707909

Abstract

BACKGROUND

Validation data for currently available indirect calorimeters is limited. The purpose of this investigation was to validate a newer indirect calorimeter system (Vmax Encore) against a criterion device (Deltatrac Metabolic Monitor) in spontaneously breathing mode.

MATERIALS AND METHODS

An n-of-1 methodology was used in which both indirect calorimeters were employed in the same subject repeatedly until 15 measurement pairs were generated for oxygen consumption (VO2), carbon dioxide production (VCO2), resting metabolic rate (RMR), and respiratory quotient (RQ). Bias was defined as a 95% confidence interval of differences between devices that excluded zero. A set of intradevice measurement pairs was also obtained to analyze the precision of the Vmax and Deltatrac (precision defined as not more than 5% of measurements being ≥5% different).

RESULTS

Both Vmax and Deltatrac precisely measured VO2 and RMR. The largest intradevice difference for RMR in the Deltatrac was 4.7% (one of 20 pairs) and in the Vmax 4.8%. On the other hand, VCO2 and RQ were not measured precisely by either device, with 10% or more of the measurement pairs differing by ≥ 5%. The Vmax was biased toward low measurement of VO2 and RMR relative to the Deltatrac. Oxygen consumption was on average 4.5 ± 2.4% lower for the Vmax device compared to Deltatrac while RMR was lower by an average of 4.1 ± 2.2%.

CONCLUSIONS

The Vmax Encore indirect calorimeter is a precise instrument for measuring VO2 and RMR in spontaneously breathing individuals, but it is biased toward lower values compared to the Deltatrac.

摘要

背景

目前可用的间接热量计的验证数据有限。本研究的目的是在自主呼吸模式下，将一种新型间接热量计系统（Vmax Encore）与标准设备（Deltatrac代谢监测仪）进行验证。

材料与方法

采用n-of-1方法，在同一受试者中反复使用两种间接热量计，直至产生15对关于耗氧量（VO2）、二氧化碳产生量（VCO2）、静息代谢率（RMR）和呼吸商（RQ）的测量数据。偏差定义为设备间差异的95%置信区间不包括零。还获得了一组设备内测量数据对，以分析Vmax和Deltatrac的精度（精度定义为不超过5%的测量值差异≥5%）。

结果

Vmax和Deltatrac均能精确测量VO2和RMR。Deltatrac中RMR的最大设备内差异为4.7%（20对中的1对），Vmax为4.8%。另一方面，两种设备对VCO2和RQ的测量都不准确，10%或更多的测量数据对差异≥5%。相对于Deltatrac，Vmax在VO2和RMR测量上存在偏低偏差。与Deltatrac相比，Vmax设备的耗氧量平均低4.5±2.4%，而RMR平均低4.1±2.2%。