Cardiopulmonary exercise stress testing

 

Cardiopulmonary exercise stress treadmill (CPEST or CPEX)

  1. CPEST is a method of quantitating exercise tolerance in a reproducible, scientific manner. The final results are, however, very dependent on accurate spirometry, on the effort of the patient, the encouragement of the tester and the willingness of the tester to take the patient to the true limits of their performence.

  2. A cardiopulmonary stress test CPEST gives more information than a standard cardiac exercise stress test (EST) in those being assessed for lung surgery. If the patient has minimal lung disease and a major cardiac co-morbidity, we may ask for a pure cardiac EST. However, on the thoracic ward a “treadmill” means a cardio-pulmonary treadmill unless otherwise stated. It is usually performed by the respiratory physicians, their technical staff.

  3. Usually a treadmill is used. A bicycle can be used as an alternative if unable to use treadmill because of arthritis etc.

  4. In interpreting a CPEST it is important to ascertain:

    1. •What protocol was used?

    2. •For how long did the patient exercise?

    3. •Why did they stop? (Chest pain, fatigue, leg pain, arthritis, stopped by technician because of tachycardia, angina etc)

    4. •Were their any ST or other ECG changes?

    5. •How many atrial or ventricular ectopics were their?

    6. •What was the absolute VO2 max (ml/kg/min)


Protocol used

  1. Bruce.

  2. One of the first protocols used was the Bruce. It was designed to test post infarct angina and its relation to ST changes. It is a very shallow protocol and many fitter patients do not reach anaerobic threshold

  3. Modified Bruce.

  4. This is a much steeper protocol suitable for the non-infarct situation for fitter patients.

  5. Naughton.

  6. Similar to the modified Bruce.

  7. Modified Naughton.

  8. Similar to the Bruce protocol, quite gentle.


Time exercised.

  1. The time a patient exercised for is a useful measure of fitness. Someone who has exercised for over 10 minutes on a reasonable protocol despite claudication, arthritis, ST changes, fatigue and the tester’s concerns, is likely to tolerate most operations.

Why did they stop?

  1. Chest pain, fatigue, leg pain, arthritis, stopped by technician because of tachycardia, angina etc.

  2. ST changes

  3. Ectopics

VO2 max

  1. Exercise Oxygen Consumption: MVO2 (Bechard D. Ann Thorac Surg 1987;44:344-9.)

  2. 50 patients undergoing 10 pneumonectomies, 28 lobectomies and 12 wedge resections.

  3. 2 mortalities and 6 morbidities.

  4. MVO2 < 10 ml/kg/min had 29% mortality, 43% morbidity,

  5. MVO2 = 10 - 20 ml/kg/min 11% morbidity,

  6. MVO2 > 20 ml/kg/min no morbidity.

Pulmonary rehabilitation

  1. Some borderline patients who are not fit for the required operation may benefit from pulmonary rehabilitation. This is only possible for fairly early tumours which are not fast-growing. The program usually lasts abpproximately 6 weeks and entails:

  2. •Smoking cessation

  3. •Optimisation of bronchodilator, anti-hypertensive and anti-anginal medication

  4. •Dietary advice

  5. •Graduated exercise program to counter-act de-conditioning

  6. •Specific breathing exercises

  7. •Education on breathing and coughing following a thoracotomy