Cardiopulmonary exercise testing

cardiopulmonary exercise testing

1. Dr. Avinash D. Arke
MD FNB

2. Introduction
Cardiopulmonary exercise testing - assessment of the integrative
exercise responses involving
pulmonary,
cardiovascular,
haematopoietic,
neuropsychological, and
skeletal muscle systems

3. THE GAS TRANSPORT SYSTEM

4. Coupling of External Ventilation
and Cellular Metabolism

5. General Mechanisms of Exercise Limitation
Pulmonary
Ventilatory
Respiratory muscle
dysfunction
Impaired gas exchange
Cardiovascular
Reduced stroke volume
Abnormal HR response
Circulatory abnormality
Blood abnormality
Peripheral
Inactivity
Atrophy
Neuromuscular
dysfunction
Reduced oxidative
capacity of skeletal muscle
Malnutrition
Perceptual
Motivational
Environmental

6. Learning objectives
1.Indications for CPET;
2.Methodology—equipment, modality, protocols, conduct of the test,
measurements and graphic interrelationships safety, and personnel
issues;
3.Measurements and graphic interrelationships, the physiologic response
to exercise, in “normal” subjects, and the consequences of
pathophysiologic derangements on exercise performance;
4.Normal reference values;
5.Interpretation, including case study analysis; and
6.Future recommendations for research.

7. The Fick equation
Fick equation states that oxygen uptake (VO2) equals cardiac output
times the arterial minus mixed venous oxygen content:
VO2 = (SV x HR) x (CaO2 - CvO2)
Where,
SV is the stroke volume,
HR is the heart rate,
CaO2 is the arterial oxygen content, and
CvO2 is the mixed venous oxygen content.
Oxygen uptake is often normalised for body weight and expressed in
units of ml O2/kg/min.

8. One metabolic equivalent (MET) is the resting oxygen uptake in a
sitting position and equals 3.5 ml/kg/min.
At maximal exercise, the Fick equation is expressed as follows:
VO2max = (SVmax x HRmax) x (CaO2max - CvO2max)

12. Respiratory exchange ratio (RER)
VO2 / VCO2
Normal – 1
With exercise 0.7 / 0.8
If > 1.1, abnormal

13. Ventilatory anaerobic threshold
VO2 at which lactate starts rising

14. Indications

15. Contraindications

16. Equipment and Methodology
Cycle ergometer
Treadmill ergometer

19. Airflow or volume transducers
1.Pneumotachograph
2.Mass flow sensor
3.Pitot tube flowmeter
4.Turbine volume transducer

21. Gas analyzers
Mass spectrometer: measure O2, CO2, N2
Separate analyzer for O2, CO2

22. Gas exchange measurement: VO2 and VCO2
VO2 = [(Vi . FiO2) - (Ve . FeO2)]/t
Vi is not commonly measured,
N2 is neither absorbed nor discharged from the capillaries
Vi . FiN2 = Ve . FeN2
Vi = Ve . FeN2/FiN2
because FiCO2 in room air is practically zero and may be safely ignored
in the calculation:
Vco2 = [Ve . FeCO2]/t

23. Bag collection method:
Douglas bag
Mixing chamber
Breath-by-breath mode

28. Exercise Testing Protocols
Maximal incremental cycle ergometry protocols
Maximal incremental treadmill protocols
Constant work rate protocol

29. Maximal incremental cycle ergometry protocols
IET protocol
3 minutes of rest,  3 minutes of unloaded pedaling the incremental
phase of exercise every minute (5 to 25 W/minute) until the patient reaches
volitional exhaustion or the test is terminated by the medical monitor
Ramp protocol
increase the work rate continuously, usually every 1 to 2 seconds in a
ramplike fashion
Standardized exponential exercise protocol
work rate is increased exponentially by 15% of the previous workload every
minute

31. Maximal incremental treadmill protocols
Bruce protocol:
the starting point (ie, stage 1) is 1.7 mph at a 10% grade (5 METs).
Stage 2 is 2.5 mph at a 12% grade (7 METs).
Stage 3 is 3.4 mph at a 14% grade (9 METs).
This protocol includes 3-minute periods to allow achievement of a steady
state before workload is increased.
Modified Bruce protocol
2 warmup stages, each lasting 3 minutes.
The first is at 1.7 mph and a 0% grade,
the second is at 1.7 mph and a 5% grade

32. Balke protocol - speed is kept constant at 3.3 mph, and elevation is
increased by 1% every minute
Modified Balke protocol - fixed treadmill speed is chosen and the
treadmill grade is increased by a constant amount each minute
Naughton, Weber, and Asymptomatic Cardiac Ischemia Pilot (ACIP)
study protocols, all of which start with less than 2 METs at 2 mph and
increase in 1- to 1.5-MET increments between stages.

33. Constant work rate protocol
Treadmill or cycle ergometry exercise
at levels approximating the subject’s usual daily activities (e.g., up to 3.0
mph on a treadmill, or up to 50 W on a cycle ergometer).
A constant work rate may be performed about 1 hour after an IET.
This test should involve at least 6 minutes of continuous exercise.
Alternatively, using 50 to 70% of the maximal work rate achieved during
an incremental exercise, a constant work rate test for 5 to 10 minutes
often achieves about 70 to 90% of O2max achieved during IET.

34. Constant work rate protocol
Used:
monitoring response cardiopulmonary rehabilitation, bronchodilators,
LVRS, medical devices
analysis of exercise tidal flow–volume loops and dynamic hyperinflation,
gas exchange kinetics, and validation of pulmonary gas exchange during
incremental exercise testing

39. Patient safety
Relatively safe
0 – 5 / 100000 exercise test (AHA)
Veteran Affairs Health Care System exercise laboratories: an event rate of
1.2 per 10000 tests (MI, VT)

45. Normal

46. Cardiomyopathy

57. Thank you !