Omnical RMR / BMR

Highly versatile and accurate

The Omnical is the most versatile and accurate indirect calorimeter for research purposes on the market. Comprised of state-of-the-art technology using the highest class precision measurement instruments, it enables customers to perform studies in various research fields.

The Omnical technology is designed to measure energy metabolism ranging from resting metabolism rate (RMR), sports performance testing (e.g. VO₂max tests) to whole body room calorimetry with high accuracy.

The Omnical RMR / BMR

The Omnical RMR / BMR indirect calorimeter is ideally suited for performing Resting Energy Expenditure, Resting Metabolic Rate or Basal Metabolic Rate measurements. It comprises of two basic parts: a gas analysis system and the data analysis/presentation software. The subject’s exhaled breath is captured with a flow–diluting canopy hood and directed to the gas analysis system. The system consists of:

1. Omnical
2. Analysis software
3. Canopy/hood

Optional

4. Validation kit

Software and data analysis

The data processing/presentation software (calorimetry software) for the indirect calorimeter system provides the researcher with means of starting and monitoring live experiments and calculating data sets.

Raw data is being passed through a calculation module that generates the result files which typically includes VO2 [ml/min], VCO2 [ml/min], Energy Expenditure [KJ/min] and Respiratory Exchange Rate (RER).

Scientific publications featuring Omnical can be accessed on: https://www.indirectcalorimetry.net/research-publications-2/  and

https://www.roomcalorimeters.com/literature/

Assessment of resting energy expenditure and nutrient oxidation by indirect calorimetry: methodological implications.

(Alcantara, 2021)  https://digibug.ugr.es/handle/10481/65383?show=full

Summary

The results of the present Doctoral Thesis show that all the metabolic carts yielded different RMR and RER measures. The Omnical metabolic cart presented better accuracy and precision than the rest of metabolic carts, although the day-to-day biological reproducibility achieved by the Q-NRG and the Vyntus CPX was similar to the one achieved by the Omnical. The post-calorimetric correction procedure did not improve neither the comparability nor the day-to-day RMR and RER biological reproducibility in the four analyzed metabolic carts. On the other hand, we observed a strong association between the day-to-day biological reproducibility assessed with the CCM Express and the CPX Ultima CardiO2 metabolic carts. Finally, the longtime interval method for IC data analysis presented the best day-to-day RMR and RER biological reproducibility in four metabolic carts.

Result

Collectively, the results of this Doctoral Thesis suggest that the Omnical is the best metabolic cart for assessing RMR and RER among the six metabolic carts analyzed. Moreover, this Doctoral Thesis suggest that the day-to-day biological reproducibility is largely attributable to the individual’s characteristics and is not improved by the application of a post-calorimetric procedure based on the infusion of pure gases after the individual measurement. Finally, among the methods for IC data analysis, the long-time interval method seems to be the most adequate for analyzing the data provided by the analyzed metabolic carts.

Figure 5 – Percentage measurement error of oxygen consumption (VO2; Panel A), carbon dioxide production (VCO2; Panel B), energy expenditure (EE; Panel C) and measurement error of respiratory exchange ratio (RER; Panel D) across metabolic carts, as determined by alcohol burning (i.e. methanol combustion; white bars) and gas infusions (black bars). The percentage measurement error was calculated as ([measured value – expected value] / expected value) × 100 for and measurement error as (measured value – expected value). * represent significant differences (paired t-test) between the methanol combustion vs. the gas infusions values (n=3). Results are presented as mean and standard deviation.

Determining the Accuracy and Reliability of Indirect Calorimeters Utilizing the Methanol Combustion Technique.

Kaviani, S., Schoeller, D.A., Ravussin, E., Melanson, E.L., Henes, S.T., Dugas, L.R., Dechert, R.E., Mitri, G., Schoffelen, P.F., Gubbels, P., Tornberg, A., Garland, S., Akkermans, M. and Cooper, J.A. (2018),  Nutrition in Clinical Practice, 33: 206-216. https://doi.org/10.1002/ncp.10070

Background

Several indirect calorimetry (IC) instruments are commercially available, but comparative validity and reliability data are lacking. Existing data are limited by inconsistencies in protocols, subject characteristics, or single-instrument validation comparisons. The aim of this study was to compare accuracy and reliability of metabolic carts using methanol combustion as the cross-laboratory criterion.

Methods

Eight 20-minute methanol burn trials were completed on 12 metabolic carts. Respiratory exchange ratio (RER) and percent O2 and CO2 recovery were calculated.

Results

For accuracy, 1 Omnical, Cosmed Quark CPET (Cosmed), and both Parvos (Parvo Medics trueOne 2400) measured all 3 variables within 2% of the true value; both DeltaTracs and the Vmax Encore System (Vmax) showed similar accuracy in measuring 1 or 2, but not all, variables. For reliability, 8 instruments were shown to be reliable, with the 2 Omnicals ranking best (coefficient of variation [CV] < 1.26%). Both Cosmeds, Parvos, DeltaTracs, 1 Jaeger Oxycon Pro (Oxycon), Max-II Metabolic Systems (Max-II), and Vmax were reliable for at least 1 variable (CV ≤ 3%). For multiple regression, humidity and amount of combusted methanol were significant predictors of RER (R2 = 0.33, P < .001). Temperature and amount of burned methanol were significant predictors of O2 recovery (R2 = 0.18, P < .001); only humidity was a predictor for CO2 recovery (R2 = 0.15, P < .001).

Conclusions

Omnical, Parvo, Cosmed, and DeltaTrac had greater accuracy and reliability. The small number of instruments tested and expected differences in gas calibration variability limits the generalizability of conclusions. Finally, humidity and temperature could be modified in the laboratory to optimize IC conditions.