Vmax and InnocorA comparison of two metabolic carts during rest and exercise

Zach Blain

Methods• The volume of oxygen consumed and utilized by working muscle per

minute during rest or exercise.

• Defined by Fick:• VO2 = Q × a-vO2 difference

• Q = SV × HR• Q= Cardiac output; SV= Stroke volume; HR= Heart rate

• Calculated as: • VO2 = [VE × (FEN2 / FIN2) × FIO2] – [VE × FEO2]

• VE= Ventilation, volume/min; FEN2= Fraction of expired nitrogen; FIN2= Fraction of inspired nitrogen; FIO2= Fraction of inspired oxygen; FEO2= Fraction of expired oxygen

• To measure Q • Pulmonary artery catheter (PAC)

• To measure a-vO2 Diff• Arterial venous catheter• blood sampling

How they work

Innocor

• Flowmeter

• Gas Analyzer

• Oxygen sensor

Vmax

• Flow/Volume

• O2 Analyzer

• CO2 Analyzer

• Flash Multi-Gas

Innocor Vmax

Purpose

The aim of this study is to compare the metabolic

measurements between Vmax and Innocor simultaneously

during rest and exercise.

HypothesisIt is hypothesized that there will be no difference between Vmax

and Innocor during rest and exercise.

Design and Protocol• Simultaneous measurements

• Baseline• 50 W• 100 W• 150 W• 200 W• 250 W• 300 W• Staged steady state

exercise - 2 minutes

Demographics

Patient DemographicsParticipants (male/female) 7 (4/3)Age (years) 24 ± 3Height (cm) 171 ± 8Weight (kg) 73 ± 20BMI (kg/m²) 25 ± 6

Absolute VO2/ VCO2 vs. Workloads

0 50 100 150 200 250 3000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Vmax

Innocor

Workload (Watts)

VO₂ (

L/m

in)

*

* Significant Difference P< 0.05

0 50 100 150 200 250 3000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Vmax

Innocor

Workload (Watts)VC

O₂ (

L/m

in)

*

Figure 2: Absolute VO2 (L/min) vs Workload (Watts) Figure 3: Absolute VCO2 (L/min) vs Workload (Watts)

Ventilation

0 50 100 150 200 250 3000

0.5

1

1.5

2

2.5

3

3.5

VmaxInnocor

Workload (Watts)

Vt (l

iter

s per

bre

ath)

0 50 100 150 200 250 3000

10

20

30

40

50

Vmax

Innocor

Workload (Watts)

RR (b

reat

hs p

er m

in)

Figure 4: Respiration rate (breaths per min) vs. Workload (Watts)

Figure 5: Tidal volume (liters per breath) vs. Workload (Watts)

Discussion

• No significant change in results for low workloads• After 200W there becomes a deviation in the results

• No significant difference in the respiration, at any workload

• VO2 and VCO2 at high workloads (300W)• Account for gas analysis• FIO2 and FEO2

Features

FeaturesSafe Yes YesStart up cost 160,000 60,000Mobility Minimal MaximalSkill required Maximal MinimalRange Rest- Maximal? Rest-Maximal?Issues

TechnicianMouthpiece discomfort

Vmax Innocor

Conclusion

Both Vmax and Innocor can attain similar

results for lower workloads, but begin to drift

during higher workloads.

Acknowledgments

• Brad Byers• Desi Fuhr• Karishma Kapoor• Linn Moore• Melissa Bouwsema• Michael Stickland• Vince Tedjasaputra

References

• Allen et al. (2013). ACSM’s Guidelines for exercise testing and prescription. Baltimore, MD. Wolters Kluwer, Lippincott Williams &Wilkins

• Beekley et al. (2004). Cross-Validation of the YMCA Submaximal Cycle Ergometer Test to Predict VO2max. Research Quarterly for Exercise and Sport. 75:3, 337-342.

• CareFusion Corporation. (2014). Vmax Encore Metabolic Cart. Retrieved from www.carefusion.com

• Innovision ApS. (2014). Innocor. Retrieved from www.innovision.dk• Stringer, W. Hansen, J. Wasserman, K. (1997). Cardiac output estimated

noninvasively from oxygen uptake during exercise. J Appl Physiol 82:908-912.

• Welch, HG. Pedersen, PK. (1981). Measurement of metabolic rate in hyperoxia. J Appll Physiol Respir Environ Exerc Physiol. Sep; 51(3): 725-31.

50 100 150 200 250 30015

20

25

30

35

40

45

50

55

VmaxInnocorPredicted VO2

Workload (Watts)

VO2

(ml/

kg/m

in)

Figure 6: Relative VO2 (ml/kg/min) vs. Workloads (Watts)

VO2 = (Watts (Watts)/ Bodyweight (kg) × 10.8) + 7ml/kg/min