Medtronic, Inc., said Wednesday that eight deaths and 270 serious or life-threatening injuries that occurred between May 1996 and September 2010 were tied to an improperly working product that it manufactured.

The Fridley-based medical device manufacturer's SynchroMed II and SynchroMed EL implantable infusion pumps-which deliver a gradual but constant stream of drugs or fluids into a patient's body-can cause “pocket fills.” A pocket fill is the inadvertent injection of all or some of the prescribed drug into the patient's subcutaneous tissue instead of the pump itself, which causes patients to get too much or too little of the drug.

Medtronic said that it is in the process of updating the labeling for its SynchroMed pumps and refill kits and including warnings related to the potential for improper injection.

Doctors rely heavily on tactile feedback to determine if the needle is correctly positioned in the pump reservoir during the refill process, according to the company. Last month, Medtronic sent a letter to doctors to remind them about the potential for pocket fills to occur during the refill procedure and to alert them about steps to ensure that the needle is correctly positioned.

Medtronic alerted the U.S. Food and Drug Administration (FDA) about the issues surrounding its SynchroMed pumps. The agency has classified Medtronic's product-labeling corrections as a Class I recall-meaning that there is a “reasonable probability” that the use of, or exposure to, the product will cause serious adverse health consequences or death. Class I recalls are the FDA's most serious designation.

Medtronic is the world's largest medical device company and Minnesota's seventh-largest public company based on revenue, which totaled $15.8 billion in its most recently completed fiscal year.