11.9 CPET Flashcards
a) List the main measures of fitness that are obtained by a cardio-pulmonary exercise test (CPET).
(4 marks)
> > Anaerobic threshold (AT):
the level of oxygen delivery (VO2)
at which anaerobic metabolism
starts to occur.
> > Peak oxygen delivery (VO2 peak).
> > Workload achieved.
b) What abnormalities seen at the time of testing in a CPET may suggest cardiorespiratory disease?
(4 marks)
A low Vo2 Max
Low anabolic threshold
Cardiac:
» Rapid rise in heart rate,
especially at low levels of work.
> > Reduced heart rate reserve.
> > Reduced peak oxygen pulse
(reflects stroke volume).
> > Pathologically altered ECG
with exercise (e.g. ST segment elevation or
depression, arrhythmia, left bundle branch block).
> > Reduction in blood pressure with exercise.
Respiratory:
» Raised ventilatory equivalent
for carbon dioxide or oxygen.
> > Spirometry abnormalities
such as significant reductions in
FVC, FEV1 or both.
> > Significantly reduced oxygen
saturations at peak exercise.
c) When might CPET, using a bike, be impractical (3 marks) and
Situations where CPET is impractical:
> > History of amputation that has
compromised ability to use a bicycle.
> > Severe peripheral vascular disease.
> > Severe arthritis, some patients
awaiting lower limb joint replacements.
> > Balance or coordination problems.
> > Inability to tolerate face mask/mouth
piece due to e.g. claustrophobia.
> > Lack of motivation.
how else can patients’ functional capacity
be assessed? (3 marks)
Other methods of assessing
patients’ functional capacity:
> > Questionnaire-based approaches such
as the Duke Activity Status Index.
> > Six-minute walk test.
> > Incremental shuttle walk test
> > CPET using a hand crank. Results not comparable to results from bike
CPET due to different muscle groups and size of muscles involved.e
d) What scoring systems can help predict perioperative risk before major (non-cardiac) surgery?
(6 marks)
Generic scoring systems:
» American Society of Anesthesiologists
Physical Status Score (ASA).
> > Physiological and Operative
Severity Score for the enUmeration of
Mortality and Morbidity (POSSUM).
Limited by the need to include a
prediction of intraoperative issues.
> > Surgical Outcome Risk Tool (SORT).
> > American College of Surgeons Surgical Risk Calculator (ACS NSQIP).
> > Charlson Age Comorbidity Index (CACI).
Scores for cardiac risk:
» Revised Cardiac Risk Index (RCRI).
Scores for respiratory comorbidity:
» Arozullah Respiratory Failure Index.
» Gupta calculators for postoperative respiratory failure and pneumonia.
» ARISCAT Risk Index.
Scores for specific operations or operation types:
» Nottingham hip fracture score.
> > POSSUM for vascular surgery (V-POSSUM).
> > Carlisle risk calculator for survival
after elective AAA repair.
