Sat27November0556PM 39

A 74-year-old man with ischaemic heart disease is undergoing a cardiopulmonary exercise test (CPX) prior to an elective abdominal aneurysm repair.

Which of these measurements taken during a CPX test alone correlates best with postoperative mortality?

(Please select 1 option)

VO2 peak

Respiratory exchange ratio

Anaerobic threshold Correct

Expired CO2

V-slope

Explanation

Cardiopulmonary exercise testing (CPX, CPEX, CPET) is an objective tool for the evaluation of cardiopulmonary function and fitness.

Parameters measured:

ECG and ST-segment analysis and blood pressure

Oxygen consumption (VO2)

Carbon dioxide production (VCO2)

Gas flows and volumes

Respiratory exchange ratio (RER)

Respiratory rate

Anaerobic threshold (AT).

An AT below 11 ml/kg/min is associated with increased mortality particularly if there is evidence of myocardial ischaemia during the test.

Prior to aortic aneurysm surgery, peak VO2<20 ml/kg and low AT are associated with postoperative complications and 30 day mortality. CPX testing can be used to risk-stratify patients in order to rationalise postoperative care facilities.

The V slope is a VO2 versus VCO2 relationship.

At the anaerobic threshold the ramp of V slope increases but is not used to predict postoperative mortality.

Reference:

Older P, Smith R, Courtney P, Hone R. Preoperative evaluation of cardiac failure and ischaemia in elderly patients by cardiopulmonary exercise testing. Chest. 1993;104:701-4.

Answer Statistics

1

12%

2

2%

3

84%

4

3%

5

1%

Times answered: 234