Final answer:
The electrodes for the 5-lead EKG should be removed before attaching the electrodes for the 12-lead EKG to avoid mixing signals from different leads.
Step-by-step explanation:
The electrodes for the 5-lead EKG should be removed before attaching the electrodes for the 12-lead EKG to Avoid Mixing Signals from Different Leads. Leads are used to describe the voltage difference between two electrodes. When using different leads simultaneously, signals from different leads may mix, leading to inaccurate readings. By removing the electrodes for the 5-lead EKG, the signals can be properly isolated and the 12-lead EKG can provide accurate information about the heart's electrical activity.