Piergiuseppe Agostoni, MD, PhD Centro Cardiologico Monzino, Istituto di Cardiologia, Università di Milano, Milano Division of Respiratory Disease, University of Washington, Physiological bases of clinical exercise testing: choosing and performing the proper test
Physiological bases of clinical exercise testing: choosing and performing the proper test. Piergiuseppe Agostoni, MD, PhD Centro Cardiologico Monzino, Istituto di Cardiologia, Università di Milano, Milano Division of Respiratory Disease, University of Washington, Seattle, WA. - PowerPoint PPT Presentation
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Piergiuseppe Agostoni, MD, PhD
Centro Cardiologico Monzino, Istituto di Cardiologia, Università di Milano, Milano
Division of Respiratory Disease, University of Washington, Seattle, WA.
Physiological bases of clinical exercise testing: choosing and performing the proper
test
Gas diffusion
O2 transport
Cardiac output
O2 extraction
Ventilation
muscle
Why a cardiopulmonary exercise test?
Etiology of exercise limitation is unknown
Disease prognosis (CHF)
Effectiveness of therapeutic intervention
Exercise prescription
Transplant evaluation
Research!
Modalities
ERGOMETER Treadmill Cycloergometer Armometer
Cardiopulmonary exercise test
GAS ANALYSIS (indirect calorimetry)
Douglas bag procedure Time-averaged systems
Breath-by-breath systems
Treadmill Cycloergometer
• Hystorical • Easy to be performed • VO2max > 5-10%• Expensive, noisy• Dangerous for some
categories of patients• Not suitable for
hemodynamic measurements
• Difficulties in assessing workrate
• Easy to assess workrate• Less expensive, less
noise
• Easy to assess VO2/WR
• Suitable for hemodynamic measurements
• VO2max 89%-95% vs treadmill
Cardiopulmonary Exercise
Test ProtocolsCostant Workload
Step Incremental Workload
Ramp Incremental Workload
VO2
Time3’ 6’ Gas kinetics Analysis
- phase 1 linked to cardiac output
- phase 2 related to exercise capacity
(Tau: 63% VO2max; T1/2)
- phase 3 (Delta 6°e 3° minute)
• Above or below Anaerobic Threshold
• Response to therapeutic intervention
CONSTANT WORKLOAD PROTOCOLS
Zhang et al.
Ramp
1-min step 3-min step
2-min step
Time (min)Time (min)
VO
VO
22 (
L•m
in (
L•m
in-1-1))
Work
Rate
(W
)W
ork
Rate
(W
)
INCREMENTAL PROTOCOLSDid the different work rate step patterns affect aerobic function parameters?
What is a Ramp What is a Ramp Protocol?Protocol?
Constant and continuous work increasesConstant and continuous work increases
Can be easily individualizedCan be easily individualized
Test duration may be better targetedTest duration may be better targeted
May better elicit a “true” VOMay better elicit a “true” VO22maxmax
2’-3’ step incremental protocol useful 2’-3’ step incremental protocol useful only if intermediate steady state needing only if intermediate steady state needing (i.e. blood sampling, haemodinamic (i.e. blood sampling, haemodinamic measures)measures)
CARDIOPULMONARY EXERCISE TESTOPTIMAL LENGHT
J Appl Physiol 1983
- What is the ideal maximal exercise test? Mode that progressively increases total body and myocardial demand in reasonable time- What is an optimal time duration?- What is an optimal time duration? 8 to 12 minutes
50
100
150
200
C B A
5 min 10 min 15 min
0
10
20
30
C B A
5 min 10 min 15 min
Peak WRWatts
Peak VO2ml/min/Kg
*
* **
*
Agostoni PG et al. Eur J Heart Fail 2005
They are influenced
Effects of work-rate ramp on peak exercise parameters in heart failure
20
60
100
140
C B A
5 min 10 min 15 min
0
10
20
C B A
5 min 10 min 15 min
Work rate ATWatts
VO2 ATml/min/Kg
*
*
*
Agostoni PG et al. Eur J Heart Fail 2005
It is not influencedIt is influenced
Effects of work-rate ramp on AT parameters in heart failure
20
30
40
50
C B A
VE
/VCO
2 slop
e
5 min 10 min 15 min
Agostoni PG et al. Eur J Heart Fail 2005
Effects of work-rate ramp on VE/VCO2 slope in heart failure
It is not influenced
Agostoni PG et al. Eur J Heart Fail 2005
Effects of work-rate ramp on VO2/WR slope in heart
failure
It is influenced
>VO2/WR slope > lenght
• Match the Person, Match the Person, Protocol, and Purpose of Protocol, and Purpose of the Test !!!!the Test !!!!
• Major Parameters.Major Parameters.
CARDIOPULMONARY EXERCISE TEST: WHICH MEASUREMENTS DOES IT SUPPLY?
Wasserman K. Priciples Exercise Testing and Interpretation. Third Edition Lippincott Williams &
non-linearly– may plateau in some– ventilatory limitation
• VT > 55% of VC
• RF– slow initially– sharp
• hyperventilation– ventilatory limitation
• RR > 55 b/min
k x VCO2[PaCO2 x (1-Vd/Vt)]
VE=
…beyond VO2… the future of CPET…
Piergiuseppe Agostoni, MD, PhDGaia Cattadori, Anna Apostolo, Mauro Contini,
Pietro Palermo, Giancarlo Marenzi, Karlman Wasserman.
VO2 = VE (FiO2 – FeO2)
VO2 = Q (CaO2 – CvO2)
VO2 = D (PcapO2 – PmitO2)
Fick
a) Cardiac output
b) A-V O2 difference- hemoglobin- Hb O2 sat
- pO2
0
2,5
5
7,5
10
12,5
15
2,5 5 7,5 10 12,5 15 17,5 20
2,00
1,75
1,50
1,25
1,00
0,75
0,50
0,25
VO2 = C.O. x C(a-v)O2
A-V Content Difference (ml/100 ml)
Card
iac O
utp
ut
(L/m
in)
0
2,5
5
7,5
10
12,5
15
2,5 5 7,5 10 12,5 15 17,5 20
2,00
1,75
1,50
1,25
1,00
0,75
0,50
0,25
VO2 = C.O. x C(a-v)O2
A-V Content Difference (ml/100 ml)
Card
iac O
utp
ut
(L/m
in)
HealthyHealthy
+ Hb
COPD
HF
Anemia
Stringer WW et al. J Appl Physiol. 82(3): 908-912
CO estimated noninvasively from oxygen uptake during exercise.
Method: INERT GAS REBREATHING
Spontaneous rebreathe (for 10-20 sec.) from a bag prefilled with an oxygen enriched mixture containing two foreign gases Nitrous oxide (N2O) is soluble in blood and its concentration decreases during rebreathing with a rate proportional to CO Sulphur hexafluoride (SF6) is insoluble in blood and is used to determine the lung volume Population: