Calibration of the System

This is a very important part of the test. It should be done before each test and does not take more than one minute. The two main causes of errors in CPX results are errors in calibration and leaks.

Analysis of the resting phase is important and already provides some insights. It is necessary to wait 3-4 minutes of resting while gas exchange is measured to ensure stability. Baseline VO2 should be between 3 and 5 mL/min/kg (but lower values may be found in patients with severe heart failure), the respiratory exchange ratio (RER) below 0.90, and ventilation quiet. Ventilatory oscillations can be observed at this stage; this is the consequence of a periodic way of breathing and is always associated with severe circulatory failure and/or pulmonary hypertension. The mechanism of this profile is not exactly known but seems to be mainly related to the very low kinetics of oxygen transport.2 It tends to diminish or disappear during the increase in workrate.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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