AED Manufactuer Defends Product After Cells 'Explode'; IAFF and Florida Officials Issue Safety Warnings As Investigation Continues

Posted: Friday, November 5, 1999 - Noon

NICOLE LOZARE and DAVE J. IANNONE
Firehouse.Com News

An incident involving an automatic external debfibrilator in October that injured two firefighters has prompted an investigation by Federal officials and the manufacturer into safety concerns surrounding lithium/sulfur dioxide non-rechargeable batteries.

The incident was one of four reported out of some 100,000 cells in Medtronic Physio-Control LifePak 500 Automatic External Defibrillators.

Officials are working to determine whether the incidents are isolated or a potential safety threat for emergency personnel and patients. Company officials are advising customers to continue using the devices.

The International Association of Fire Fighters called for an inquiry by the Food and Drug Administration and the National Institute for Occupational Safety and Health (NIOSH) within days after two Florida firefighters sustained injuries when a battery cell ruptured while the unit was being inspected. They also issued a safety alert.

Medtronic Physio-Control The LifePak 500 AED Medtronic spokeswoman Sandy Higgins said company officials are investigating four reported lithium battery incidents this year, but there have been no recalls and the company is advising customers to continue using the units. Discuss It: Firehouse.Com BLS/First Responder Forum

THE FIRST REPORT

The Oct. 15 incident happened at Okaloosa Island Fire Station #4 in Okaloosa County.

During a regular morning check of the department's AED, the unit was turned on and then quickly shut off, according to Shayne Stewart, president of the Okaloosa Island Fire Fighters Association.

"After the firefighter brought the unit in to [Shift Captain Steve Early], the unit was turned on again and [it advised] to replace battery," he said.

The captain removed the battery, then reinserted it and set the unit on the watch desk in the station. The unit went into a "self test mode."

"We just thought it might have been a loose connection," Early said today, his first day back to work since the incident. "[Assistant Chief Doug Draxler] hit the 'on button' and [the AED] blew up."

The unit -- which had been placed in service recently -- was not destroyed, but the back cover of the battery compartment was blown away from the unit.

Both firefighters were taken to an area hospital after being treated on the scene. They were released a few hours later. Draxler has returned to work but lost some strength in his right arm. He was scheduled to have an MRI soon, Stewart said.

Early and Draxler have both reported respiratory problems, attributed to the release of the sulfer dioxide gas inside the cell.

"I've got some upper respiratory problems," Early said. The incident may result in long term pulmonary problems for both men.

"I just came back to duty today just to see how I do," Early said. "We don't have any light duty here so you have to be able to do it all."

'EXPLOSION' OR 'VENTING'

"Physio-Control is calling [what happened] a venting, but it vented well because it blew the back end off the AED blew the desk onto the floor," Early said. "And the assistant chief was knocked out the front door of the office."

Richard Duffy, IAFF's director of occupational health and safety, said Draxler received first-degree burns to one hand from the heat of the "blast."

Medtronic officials initially said that no firefighters were burned, but later acknowledged that one had been treated for first-degree burns.

A company statement said there was "no evidence of fire or heat-related damage and no explosions associated with any of these events," a fact that has been debated among Florida officials.

"There was an explosion ... we're not talking about two rookie firefighters, this is a captain and an assistant chief who witnessed the incident," Duffy said.

Official Investigation Photo Photo taken several hours after the Okaloosa incident by a manufacturer's representative.

"The unit was blown to the floor and the firefighters pushed back by the force ... there was heat and a sound that shook the station," Stewart said. "[The AED] launched itself."

After safety alerts were issued by the Florida Fire Marshal's office and the IAFF, a second unit was found to have failed in a neighboring Florida jurisdiction, Red Bay.

In that case, the unit had not been checked for several days and was only discovered after the safety alert. There were no witnesses to the incident in that case. Florida officials said the circumstances appeared to be similar, in that the rear of the AED was blown away from the back of the unit, according to the state fire marshal. Local officials reported that the vehicle housing that unit also suffered minor damage.

"All batteries, whether used in a medical device, cell phones, flashlight or any other application, are packages that chemically generate and store electrical energy," Medtronic Physio-Control President Richard O. Martin said in a statement.

"The percussion was felt throughout the station," Stewart said. "Plastic shrapnel was thrown about the office"

Charles Clark, of the Florida State Fire Marshal's Office, said the safety alert to the state's fire and emergency medical agencies was intended to inform them of a potential problem during the investigation process.

"Our first action was to put out a fax to all EMS organizations around the state just to give them a heads up," Clark said. "At this point in time we know no cause. As we get new information we'll send it out."

Both units in Florida were inspected by the FDA and NIOSH and were then sent back to the manufacturer in Washington state. Company officials reported on their web site that the units were not destroyed in either Florida incident and that they worked when engineers inserted new batteries.

"We certainly wouldn't recommend that these specific units be placed back in service without repair," Medtronic spokeswoman Sandy Higgins said.

The web site was later updated to note "the bottom plate of the unit was broken in all cases, so the devices could not and should not have been put back into service."

"The major reason we use [Lithium Sulfur Dixoide] batteries is because the maintenance required is minimal and they have a very long life," Higgins said.

Official Investigation Photo
The back of the damaged LifePak from Okaloosa Island. The unit had been on the desk at the time of the incident, but "was blown" to the floor when the battery "exploded," Stewart said.

Higgins added that of more than 25,000 LifePak 500 units in operation, problems had only been reported in the two Florida instances and two others earlier this year. One of those units was in a law enforcement vehicle while the second was aboard an airplane, she said. No injuries were reported in either case and both were forwarded to the FDA for further investigation.

The cells in question are manufactured by SAFT.

"We're working very, very closely with Micropower, the battery assembler, and Physio-Control in trying to understand what is happening that caused this," SAFT head of sales Detlef Stevenson said.

Stevenson said the cells involved are four of about 500,000 in use worldwide. In addition to the Physio-Control incidents this year, he said he was aware of one other failure of a cell that was unrelated to the other four.

He added that the D-sized cell used by both Medtronic and Survivalink was developed specifically for use in the AED application. It is similar to a cell that SAFT manufactures 6 million of each year with no reported problems, Stevenson said.

The SAFT lithium/sulfur dioxide cells used in AEDs have been manufactured since 1993 or 1994, he said.

FEDERAL OFFICIALS INVOLVED

The FDA is the federal agency responsible for the regulation of medical devices. Spokeswoman Sharon Snyder said she was not aware of the earlier incidents but confirmed that the agency was investigating the incidents reported in Florida.

"We were contacted by the [IAFF] and are investigating along with [NISOH]," she said. I don't have any further details beyond that, its really hard to say [when the investigation] will be completed."

"We're proceeding expediciously," NIOSH spokesman Fred Blosser said earlier this week. "We're doing an evaluation and a report will be issued when the investigation is completed, but at this point there is no finding yet."

Courtesy Okaloosa Island Fire Dept Another view of the battery compartment

LITHIUM TECHNOLOGY

Other AED manufactuers that use the same type of battery cells are keeping an eye on developments in the Florida cases.

"[We use] the same technology, but our batteries have more differences than similarities to the Physio-Control modules," SurvivaLink Vice President of Engineering Ken Olson said. "We use six cells instead of four with different voltage."

But Olson added that any recall or potential problems with SAFT's cells may have an impact on his company's products.

"If it affects ours we would change ours, but right now it does not appear to be relevant to ours," he said.

Lithium is the newest battery technology used in AEDs, industry experts said.

The types of lithium batteries that are currently used in AEDs are lithium/sulphur dioxide and lithium/manganese dioxide. Lithium batteries have very high energy density, are very lightweight and can withstand harsh conditions.

The batteries also have a very long shelf life, lasting five years or more. However, the units are not rechargeable and must be replaced when the cell dies.

Medtronic said it did not go with the manganese dioxide batteries because of its temperature storage requirements. Lithium/sulfur dioxide batteries can be stored in a broad range of temperatures, while the manganese cells must be stored above zero-degrees Celcius, Medtronic officials said.

But at least one other AED manufacturer said they went with manganese dioxide cells because of certain safety characteristics of the sulfer cells. He said he could not elaborate on specific concerns.

Hewlett-Packard/Heartstream spokesman Chuck Little said their batteries are smaller cells with lower energy.

"Manganese is used in cameras and other devices and has been around for a longer time," he said. "We did several research investigations and in the end chose [lithium/manganese dioxide] because there was some risk with that chemistry and decided to stay away from it for use in our AED's."

NO RECALL PLANNED

Medtronic is conducting an investigation of its own into the four incidents, Higgins said.

"We have a whole team working through the investigation plan, including Medtronic Physio-Control engineers, representatives from the battery cell manufacturer, engineers and laboratory facilities from another Medtronic company and an indepenant battery expert," she said.

Thus far, Higgins said, engineers have not been able to duplicate the failure encountered in the four incidents. No recall is planned.

The investigation also includes evaluating the cell features, chemical analysis of the cells, looking at the history for each of the failed units and evaluating all production records at Physio-Control and at the battery manufacturer site to identify any changes.

lithium/sulfur dioxide batteries are used extensively in the armed forces, although officials are aware of potential safety issues.

Officials from the Hazardous and Medical Waste Program of the U.S. Army Center for Health Promotion & Preventive Medicine in Aberdeen, Md. issued a fact sheet in July of this year about the batteries.

The fact sheet includes the following tips for use of lithium/sulfur dioxide batteries:

• The batteries contain pressurized SO2 gas, so do not abuse or allow to rupture.
• If you hear a hissing sound or smell an irritating gas, turn off the equipment and leave the area until any signs of danger have passed.
• Do not use halon fire extinguishers to combat fires involving lithium sulfur dioxide batteries. Use an approved Class-D fire extinguisher such as Lith-X.
• If the battery compartment becomes hot to the touch, turn off equipment and cool battery for at least one hour before removing.
• Never test the battery with conventional test sets not specifically designated to test lithium sulfur dioxide batteries.
• Do not use any battery past its expiration date.
• When replacing batteries, replace all of the batteries at the same time with the same contract number, lot and date code. Never mix partially expended batteries with new batteries.
• Batteries should be stored in a noncombustible building or a structure with sprinklers, if available. Other hazardous materials should be appropriately segregated from the batteries. Batteries stored for disposal should be kept cool, dry, away from open flame, heat, combustibles, at least 2 inches from another battery, and in well ventilated areas.

AEDs: LIFE SAVERS

The American Heart Association estimates that 20,000 or more unnecessary deaths could be prevented each year if AEDs were more widely available to firefighters and EMTs, as well as to non-traditional first responders such as police, security guards and flight attendants.

Annually, an estimated 250,000 people in the United States alone die due to sudden cardiac arrest. Early defibrillation by first responders -- less than 5 minutes after ventricular fibrillation, the most common arrhythmia that causes cardiac arrest -- could save hundreds of lives each day, increasing chances for survival by as much as 50%, according to the AHA. .

Ultimately, the AHA hopes to place defibrillators in high traffic public places such as stadiums, malls and office buildings for use by the general population. According to the organization, only about 30% of EMS organizations nationwide utilize an AED program.

'NOT A WITCH HUNT' AGAINST AEDs

Duffy said the IAFF's primary concern in responding to the Florida incidents is firefighter and patient safety.

"This [is] not a witch hunt against the manufacturer or AEDs in general," Duffy said. "The AEDs have been instrumental in providing patient care for the fire service."

"We just made a response to an incident where firefighters were injured and there is potential for further problems," he said. "We're just waiting to hear [from the FDA and NIOSH] now ... it's obviously a battery issue but we're not really sure whether it was a freak incident of if there is a real problem with these battery cells."

All Lifepak 500 battery units in the two Florida counties where the incidents occurred have been replaced with rechargeable lead-acid cells, officials said. The company's web site was scheduled to be updated by today with further information on the investigation.

• Lithium/sulfur dioxide batteries are primary batteries. That means they cannot be recharged. Attempting to recharge these batteries will result in an internal short-circuit, overheating and cause the safety pressure relief mechanism to operate and vent sulfur dioxide gas. DO NOT attempt to recharge these batteries or use them in a circuit that would allow a reverse current to flow in the battery.
• The battery contents are under pressure. The battery is designed with a safety pressure relief mechanism to vent excess pressure. DO NOT short circuit or expose these batteries to high temperatures.
• The battery contains lithium metal, which is very reactive with water. DO NOT open, puncture or crush these batteries.
• The battery contains sulfur dioxide gas, which can cause respiratory distress if released in confined areas or inhaled in significant concentrations. DO NOT open, puncture, crush, short circuit or expose these batteries to high temperatures.

Related Links

• Medtronic Physio-Control Statement
• IAFF Safety Alert
• Florida State Fire Marshal's Office
• NIOSH - Fire Fighter Fatality Investigation and Prevention Program
• U.S. Army lithium/sulfur dioxide Fact Sheet
• Lifepak 500 AED Home Page
  
• Medtronic Lithium Battery Fact Sheet in PDF Format
  (Requires Adobe Acrobat Reader)
• AHA Chain of Survival
• About Lithium/Sulfer Dioxide Batteries