How to choose disposable ECG electrodes
Ag/AgCl sensors, solid vs wet gel, foam vs cloth backing, adult and paediatric sizes, AAMI EC12: what to specify for ECG electrodes, plus skin prep tips.
In short: for most monitoring and resting ECG, choose Ag/AgCl electrodes with solid (hydrogel) gel and a foam or soft backing, in the right size for the patient, with evidence of conformity to ANSI/AAMI EC12. Good skin preparation matters as much as the electrode.
The sensor: Ag/AgCl
Silver/silver chloride sensors convert the ionic signal in skin and gel into an electrical signal with low, stable offset. They also recover quickly after defibrillation, which is why they are the standard for monitoring, resting ECG and stress testing. Carbon or tin sensors are cheaper but noisier and slower to recover.
Gel: solid or wet
| Solid (hydrogel) | Wet (liquid) gel | |
|---|---|---|
| Signal at application | Good once settled | Very fast, low initial impedance |
| Wear time | Long, gel does not run or dry quickly | Shorter; gel can dry out |
| Skin comfort | Gentle, less irritation, clean removal | More residue |
| Typical use | ICU and ward monitoring, resting ECG, paediatrics | Short tests, stress testing where movement is heavy |
Backing: foam, cloth or tape
Foam backing is cushioned and resists moisture, which helps on sweaty skin and in warm wards. Cloth or non-woven tape backings are thinner and more breathable for long wear. For movement-heavy settings, look for a strong adhesive ring around the gel.
Size
Adult electrodes are commonly around 50–55 mm across; paediatric and neonatal electrodes are smaller (around 30–35 mm) so they fit small chests without overlapping. The PolarCraft™ ECG electrodes come in 55 mm adult and 35 mm paediatric sizes, with solid gel, foam backing and a U.S.-made Ag/AgCl sensor.
What to ask for in a tender
- Conformity to ANSI/AAMI EC12, which sets limits on AC impedance, DC offset, noise and defibrillation recovery.
- Sensor material (Ag/AgCl), gel type, backing material and diameter.
- Snap type compatible with your lead wires.
- Shelf life and storage conditions; gel quality depends on the pouch staying sealed.
- Latex-free declaration, ISO 13485 manufacturer certification and DRAP status.
Getting a clean trace
- Clip, do not shave, excess hair.
- Clean the site and let it dry; remove lotion or oil.
- Lightly abrade if the skin is oily or calloused.
- Use electrodes from a freshly opened pouch and reseal the pouch.
- Attach lead wires before applying, or support the wire so it does not pull on the electrode.
- Replace monitoring electrodes as your ward policy directs, typically every 24 hours or when the gel dries or the adhesive lifts.