Why ECG and CTG traces fade — and how to store thermal paper
Heat, light, humidity, PVC sleeves and hand rub fade thermal ECG and CTG records. How to store unused paper, file printed traces and keep records readable.
In short: thermal ECG and CTG traces fade or darken when exposed to heat, light, humidity, plasticisers and solvents. Keep unused paper sealed, cool and dry. Store printed records in paper folders or envelopes, away from PVC sleeves and alcohol hand rub, and scan important records for the long-term file.
Why thermal records fade
Thermal paper carries a colourless coating that turns dark where the recorder’s print head heats it. The reaction can continue or reverse after printing. Heat and sunlight darken the background; plasticisers, oils, solvents and alcohol can bleach the trace.
What damages records
| Cause | Effect | Avoid by |
|---|---|---|
| Heat (hot store rooms, vehicles, near equipment) | Background greys, contrast drops | Store below about 25 °C |
| Direct sunlight and strong light | Fading and yellowing | Keep in closed folders and cabinets |
| High humidity | Curling, coating damage | Dry storage, sealed packs until use |
| PVC sleeves, cling film, some adhesive tapes | Trace fades where it touches the plastic | Paper envelopes or polypropylene/polyester sleeves |
| Alcohol hand rub, solvents, oils | Bleached patches | Handle records with dry hands |
| Carbonless forms and fresh photocopies | Chemical transfer onto the trace | Store separately |
Storing unused paper
- Keep packs in their sealed wrap and carton until needed.
- Store cool, dry and dark; avoid stacking cartons against hot walls or roofs.
- Rotate stock first-in, first-out and check the shelf life on the label.
- In hot, humid cities, order in quantities you will use within the shelf life rather than one large annual buy.
Keeping records
For records that must be kept, scan or photocopy the trace onto plain paper soon after printing and file the copy with the patient record. Many hospitals now attach a scanned image to the electronic record and keep the thermal original only for the short term.
Choosing paper
Use paper made for your recorder model — see the ECG paper size guide. Correctly matched paper also prints with the intended darkness; poorly matched paper can need a hotter print head setting, which shortens head life. EchoGrand™ recording paper is supplied in sealed packs from cool, dry depot storage.