The Medicines and Healthcare products Regulatory Agency (MHRA), United Kingdom posted a field safety notice concerning SynchroMed Implantable Infusion Pump, manufactured by Medtronic.
The SynchroMed priming bolus function is intended to quickly advance drug from the pump reservoir to the catheter tip to allow for therapy initiation while the patient remains under medical supervision. Although drug is not intended to be delivered to the cerebrospinal fluid (CSF) during the priming bolus, mixing of the drug and non-drug (sterile water/CSF) fluids occurs at the high infusion rates used during a priming bolus. Mixing results in the unintended delivery of drug prior to the end of the programmed bolus, as well as dilution of some of the drug remaining in the catheter at the end of the bolus. Patients will receive unintended drug at a high rate of infusion in the CSF during the priming bolus, and a period of reduced concentration of drug will occur following the priming bolus.
Medtronic has performed preliminary bench testing of pumps and catheters to characterize the extent of drug mixing during a priming bolus. It is clear that the amount of drug delivered during the priming bolus procedure is related to the concentration of the drug; however clinical relevance is not fully understood. As part of the evaluation of the priming bolus, Medtronic also reviewed previously reported adverse events of overdose, underdose, and death following an infusion system implant or revision. Since drug mixing will occur any time the priming bolus is used with a SynchroMed pump, it is reasonable to expect that the resulting unintended drug delivery is a contributing factor to adverse events involving overdose and underdose. These adverse events will vary depending on the drug being infused, but could include lack of therapeutic effectiveness, confusion or altered mental state, sleepiness, nausea, respiratory depression, coma or death.
Medtronic recommends the following published guidance for managing all patients with intrathecal therapy:
Continue use of the priming bolus procedure to ensure that therapy is initiated while the patient is under medical supervision.
Monitor all patients following start or restart of intrathecal therapy, as recommended in their field safet notice. The post-procedure monitoring period will depend upon specific drug, dose administered and patient co-morbidities.
Consider priming the pump prior to implant in the patient and before connection to the catheter (back table prime) to decrease the risk of overdose, especially in patients receiving higher concentration opioid drug solutions and low total daily dose.
Educate caregivers and family members to recognize the signs and symptoms associated with intrathecal drug therapy complications.
Patients who are receiving intrathecal baclofen and who receive a catheter-only priming bolus with or without a CAP aspiration will take longer to reach full intended drug concentration. Dose titration may need to be supplemented with oral baclofen to treat spasticity until the optimal intrathecal dose is obtained.
Physicians should advise patients to avoid using concomitant drugs that may cause respiratory or CNS depression while intrathecal therapy is being initiated or resumed.
For details, please refer to MHRA website
http://www.mhra.gov.uk/Safetyinformation/Safetywarningsalertsandrecalls/fieldsafetynotices/CON286760
If you are in possession of the product, please contact your supplier for necessary actions.
Posted on 17 June 2013