BME 462 Electrode selection, testing and placement Zexi Liu, Ashley Mulchrone, Yue Yin 09/30/2014

Electrode Selection Dry-Contact and Noncontact Biopotential Electrodes:Methodological Review, Yu Mike Chi etc.

Wet Electrode Reusable Low-cost Produce reliable signals in different conditions Adhesive material to lower skin impedance, buffer electrode against mechanical motion Most common in clinical setting

Floating Electrode Metal disk is recessed, swimming in the electrolyte gel It is not in contact with the skin Reduces motion artifact

Dry Electrode Flexible dry surface-electrodes for ECG long-term monitoring, Klaus-Peter Hoffmann and Roman Ruff Direct contact with skin No electrolyte Use moisture on skin Work well for quick measurement Motion artifact Ex. Polysiloxane framework with conductive nano-particle

Non-contact Electrode Dry-Contact and Noncontact Biopotential Electrodes:Methodological Review, Yu Mike Chi etc. Gap between skin and sensor No dielectric layer Measure through hair, clothing or air A need to design amplifier to acquire signals

Electrode Placement 3 Lead ECG Einthoven’s Triangle 2 leads (3 rd can be calculated) 4 electrodes Current Standard – any part of arms/legs below the shoulders and the gluteal fold Shoulders and wrist are approximately equal

Electrode Placement Mason-Likar placement – mainly used for exercise Diminishes QRS complex Rightward axial shifts Torso placement Obscure myocardial infarction (create or mask) Motion artifact – muscle noise Bone Muscle StandardMason-Likar