UPDATED July 24, 2014, with comment from CareFusion.

CareFusion (NYSE:CFN) drew another warning letter from the FDA last month after an inspection last year revealed unapproved device changes and quality control process problems at a plant in Vernon Hills, Ill.

The June 6 letter asks CareFusion to "immediately cease activities that result in the misbranding or adulteration" of its anesthesia breathing circuit, the Denver ascites shunt and the Denver percutaneous access kit with ascites (peritoneovenous) shunt, including "the commercial distribution of these devices."

Inspections in September and November of last year found that CareFusion made changes to the heated ventilator & anesthesia breathing circuit without letting the FDA know, according to the letter. The San Diego-based company changed materials on the Y-connector used in the device "without studies for leachables and extractables or biological effect," the FDA said.

"The changes to the gas pathway material can impact the safety of the device and quality of the gas condensates for the patient. Therefore, a new 510(k) is required," according to the letter.

Similarly, materials and manufacturing process changes for the Denver ascites shunt and Denver PAK with ascites (peritoneovenous) shunt were not cleared through the watchdog agency, the FDA said.

"These changes can impact the safety and effectiveness of the device; therefore a new 510(k) is required," according to the letter.

CareFusion also "failed to adequately establish procedures for corrective and preventive action" for the Denver devices" and "failed to investigate, where necessary, complaints involving the possible failure of a device to meet any of its specifications," the agency said.

"Specifically, your firm has been aware since August 2011 of complaints of debris/particulate matter with the Denver Ascites Shunt and Percutaneous Access Kit with Ascites Shunt," according to the letter. [Y]our firm has received thirty-two (32) complaints for particulate matter/debris issues associated with the Denver Ascites Shunt and Percutaneous Access Kit with Ascites Shunt since August 2011. Review of ten of the thirty-two complaint investigations revealed that all of the complaints contained the same language, ‘A review of complaint data identified a previous complaint with a similar failure mode. Review of the previous complaint investigation noted corrective actions including remedial training and improved CME (controlled manufacturing environment) requirements were implemented for the previous complaint.’ Your firm could not locate the ‘previous complaint’ or associated complaint investigation and corrective actions referenced in the ten reviewed complaint investigations."

The company also "failed to evaluate and select potential suppliers based on their ability to meet specified requirements" and "failed to adequately establish requirements that must be met by suppliers," the agency said.

"A re-inspection by FDA will be conducted to verify the adequacy and effective implementation of the corrective actions," according to the letter.

CareFusion director of public relations Troy Kirkpatrick told MassDevice.com via email that the company immediately put a hold on shipments of both products after receiving the June 6 FDA warning.

"However, since then we have also met with the FDA and they have approved a plan for the immediate re-commercialization of our Denver shunts product, as well as our plans to transition customers from our heated breathing circuits to Fisher & Paykel heated breathing circuits. We are the exclusive U.S. distributor for Fisher & Paykel respiratory products and sell them as part of our product portfolio," Kirkpatrick wrote. "We take these matters very seriously and have invested significantly to strengthen our quality system and regulatory compliance and controls. We are cooperating fully with FDA to resolve these matters as quickly as possible."