SMTL Medical Disposable Datacard
MRI safe/conditional Electrodes (General Information)
|All Wales Contract:||ECG Electrodes, Diathermy plates, Defib pads|
|Sterility Status:||Non Sterile.|
|Usage Status:||Single use.|
Many Trusts need to know whether the electrodes theywill be using in MRI suites are acceptable for MR use. This datacardsummarises the situation with regards to the Welsh contract electrodesand explains why there is unlikely to be a specific MRI compatibleelectrode on the contract suitable for all machines.
MHRA DB2007(03) ("Safety Guidelines for MagneticResonance Imaging Equipmentin Clinical Use") uses the following definitions:
- MR CONDITIONAL - An item which has been demonstrated to pose no knownhazards in a specified MR environment with specified conditions ofuse. Field conditions that define the specified MR environment includefield strength, spatial gradient, dB/dt (time rate of change of themagnetic field), radio frequency (RF) fields, and specific absorptionrate (SAR). Additional conditions, including specific configurationsof the item, may be required.
- MR SAFE - an item whichposes no known hazards in all MR environments
- MR UNSAFE - an item which is known to pose hazards in all MRenvironments.
The same document discusses the requirement for patient monitoring,stating: "Accessories to monitoring equipmentshould also be checked for compatibility e.g. ECG leads andelectrodes.", noting that ECG connectors have been known to causeburns during MRI.
The bulletin also states that to avoid burns, "ensure that you arefamiliar with and follow the manufacturer's instructions at all times.This includes using only the monitoring equipment, ECG wires, leads,electrodes and accessories recommended by the MR system manufacturer."
Paragraph 4.12.13 gives specific advice on patient monitoring.
Therefore, for the Welsh contract, manufacturers who make a claim fortheir electrodes as either MR-safe or MR-conditional will be expectedto provide WHS with a statement explaining the status of theirdevices, and how this has been validated. In the case ofMR-conditional, they will be expected to provide details of thespecified MR environment for which they present no hazard. The MR status as supplied by the contract elecrode manufacturer(s) will beavailable with the contract documentation.
As of June 2009, Wales has 19 MR systems in use (data courtesy ofAndrew Ward, Welsh Health Estates), from Philips, Toshiba, Siemens, GEand Hitachi. As the advice from the MHRA clearly states that you should use "onlythe monitoring equipment, ECG wires, leads, electrodes and accessoriesrecommended by the MR system manufacturer", then each Trust/Departmentmust satisfy themselves with regards to the acceptability of thedevices and accessories they use. There is no guarantee thatthe contract products will be suitable for their equipment.
Please inform SMTL of any inaccuracies noted or changes requiredin this datacard.
This datacard has been prepared as an aid to contracting forpurchasers in the NHS in Wales, and shouldnot be used as a substitute for literature, instructions or training from the manufacturersof the devices.
Products mentioned in this datacard are for illustration purposes onlyand should not be seen as an endorsement of these products.