Medtronic Inc. said Wednesday that infusion pumps that deliver chemotherapy and pain medications were linked to eight deaths and 270 serious or life-threatening injuries between May 1996 and September 2010.

Injections during refill procedures known as pocket fills can cause patients to get too much or too little of a medicine administered by the infusion pumps, called SynchroMed II or SynchroMed EL, Medtronic said in a statement. In at least some of the problem cases, the drugs were injected directly into the patients all at once rather than gradually through the pump.

The Fridley-based company has revised the labeling on its products to help doctors position the needle during refills.

Meanwhile, the Food and Drug Administration has classified the corrections being made to the product's label as a Class I recall, meaning there is a "reasonable probability" that inappropriate use of the product could result in serious injury or death.

Medtronic isn't pulling pumps from the field but is telling doctors to make sure they fill them correctly.

The FDA warned Medtronic in 2009 for failing to correctly report and fix problems with the quality systems involved in manufacturing the SynchroMed pumps.

Medtronic shares rose 60 cents to $40.20 in trading Wednesday.

Bloomberg News and Star Tribune staff writer Janet Moore contributed to this report.