4. CPET

Question 1

Describe how CPET is performed and list variable measured

Answer 1

Bike ergonometer or treadmill

12 lead exercise ECG

BP Cuff

Mouthpiece for gas analyser

Connected to test computer

Subject exercises for determined period
incremental resistance
resp CVS metabolic variables collected & analysed

** Bruce Protocol

Question 2

Vary Measured in CPET

Answer 2

FiO2
Et O2
VO2

ETCo2
VCO2 (Co2 output)

TV
RR
SpO2
Work rate

Question 3

Variables calculated

Answer 3

AT anabolic threshold

Ve./VCO2 (mv / unit decrease CO2)

Question 4

Anabolic Threshold

Answer 4

O2 consumption mL/mg/min

@ which subject supplement Aerobic metabolism
with anaerobic
to maintain VO2 (transition point)

@ AT VCO2 Increase disproportionally 
to VO2
excess lactic acid release
excreted via ventilation from lung
w/ HCO3 buffer

Question 5

AT calculation

Answer 5

V slope method (plot VCO2 against VO2)
identifying take off from a line of unity

AT occurs @ lower CO2 level
<11mL/kg/min
and espec if a/w ST Segment changes = increased risk surgical mortality

Question 6

Ve/Veco2

Answer 6

Ratio minute ventilation to volume of CO2 produced

Measure of lungs ability excrete Co2

Raised in severe COPD
H Fail
P. HTN
Use additional indicator of increased risk for major surgery

Question 7

Indications for CPET

surgical

Answer 7

Surgical

Indication of srugical morbidity & mortality for major thoracic / vascular / abdominal surgery

incl risk of post op cardioresp complication

Useful predictor for post op d/c destination

** “prehabilitation” before major surgery

Question 8

Indications for CPET

Non Surgical

Answer 8

Assessment of ?SOB

Prognosis in Hfail or post tplx heart

Assessment respiratory function in COPD
Post lobectomy /pneumonectomy patients

Assess response to Rx CF & pHtn

Function assessment recovery of MODS failure post ICU

Fitness of athletes