Medical Device Daily Washington Editor
There once was a saying in science fiction television that resistance is futile, but the field of modern electronics sometimes offers examples of when resistors are futile, too.
The Feb. 5 warning letter to Cardiac Science Corporation (CS; Bothell, Washington), makers of automated external defibrillators (AEDs), focuses largely on corrective and preventive action in association with malfunctions in the firm's line of AEDs, and the short read on the warning letter is that resistors and other electronic components used in the units are the source of the infrequent problem, even though the company's initial response to a query by Medical Device Daily suggested that CS disagrees.
The warning arrived in the company's mailbox about the time the firm announced the recall of more than 12,000 AEDs due to a potential for malfunction that FDA said could terminate a defibrillation procedure (Medical Device Daily, Feb. 5, 2010). That recall came scant months behind a voluntary correction reported late last year (MDD, Nov. 24, 2009) that the firm undertook grudgingly, asserting at the time that what was described as a software-related problem was likely to show up in only one of every 75,000 units.
The inspection that gave rise to this warning letter occupied an unspecified number of days between Sept. 1 and Oct. 1, 2009, and CS evidently had only modest luck at best with its Oct. 16, 2009 response to the 483 despite getting the response to the agency within the required 15-day time frame.
The warning letter led with a multi-point citation dealing with corrective and preventive action (CAPA), stating that no corrective actions “have been identified and initiated“ for distributed Powerheart AEDs “that contain suspect [redacted] resistors.“ FDA says that the firm opened a CAPA on April 16, 2008, to deal with three resistor-related issues, including that the unit “will continuously“ produce a message instructing the operator, “do not touch patient, analyzing rhythm“ after the pads would have already been placed on the patient.
Another problem included in this first citation is that the unit “will continuously say 'peel second pad and place on lower chest as shown' after the second pad has been placed,“ according to the warning letter. The agency also claims that a source of noise, presumably of the electromagnetic variety, could affect the electrocardiogram and “prevent therapy delivery on a shockable rhythm.“
According to FDA, the company's CAPA file for this episode indicates “that failed resistors are not always detected during unit self-testing and can result in a failure to deliver the therapy,“ and that “a short term corrective action of using screened resistors for new production was implemented on August 17, 2009.“ FDA states that “no correction was identified and implemented for distributed AEDs“ and that 16 additional complaints came in after the CAPA opened, which apparently had not been closed by the onset of the inspection, last Sept. 1.
As for the firm's response to this finding, FDA noted that a proposed software fix “is only a method of detection and will not prevent resistor failures.“ The warning letter also asserts that the response did not demonstrate “that all actions needed to correct and prevent recurrence of a nonconforming product [were] identified“ in the firm's proposed fix.
In another portion of the overall CAPA citation, FDA alleged that the firm had undertaken no corrective action “with respect to distributed Powerheart AEDs that contain“ what FDA described as “suspect . . . relays.“ CS is said to have opened a CAPA in February 2009 “to address the issue of failed contact resistance in“ the relays, the identity of which was redacted. The warning letter says that this CAPA dealt with events during which “failed contact resistance“ triggered voice prompts from the AED stating, “analyzing rhythm“ and “check pads“ prior to when the pads would have been placed on the patient.
FDA asserts that CS deployed a fix for new units via a “100% component screen using [redacted] after assembly . . . along with changes in the final test system,“ but that the company failed to fix the affected units that were already in the field. The warning letter says that 38 complaints related to this problem “were received after April 2009,“ when the in-house correction was implemented for new units. As was the case with the resistors, FDA asserted that a fix to the software “will not prevent the failures.“
FDA's Seattle district office, which authored the warning letter, notified Cardiac Science that it was five days late in filing a medical device report for an event that took place Dec. 27, 2007. Manufacturers are required to file MDRs within 30 days, and CS is said to have waited 35 days, until Jan. 31, 2008, to file an MDR. The warning letter adds that FDA “notified your firm in June, 2008, that two MDRs were required to be filed“ for this event, “one for each device noted in“ the incident, although the warning letter offers no further regarding the incident in question. CS is said to have “filed a second MDR in June, 2008“ to correct the situation.
MDD obtained an e-mailed statement from CS on Tuesday that suggests that the company does not see the electronic components as the central issue. Joe Hage, the firm's director of marketing communications, told MDD via e-mail, “We have been in communication with the FDA over the past few days and have provided them with additional information concerning each of the issues.“ He said that CS has made “significant progress . . . in improving our quality systems“ and that this progress includes work done on “the effectiveness of the software update,“ which the company “will begin making available to our customers this month.“
Hage indicated that the company is “working on our formal written response to the warning letter,“ which he noted “is due within the next week or so.“ He could not predict when FDA might issue a close-out letter.
After further communication, Hage informed MDD via e-mail that “in the case of a component at issue, based on the remote chance this issue would contribute to an inability to deliver therapy in a resuscitation attempt, we believe updating the self-test features of the device to identify if the issue has occurred is the most realistic and effective method to address the issue.“ He also said that in instances in which “a product's self-test feature indicates that an issue exists, the customer should contact us for return and replacement of the product.“ Hage closed by saying that CS has “communicated this to the FDA.“
Mark McCarty, 703-268-5690;