HEATED-WIRE BREATHING CIRCUIT SAFETY ALERT

HEATED-WIRE BREATHING CIRCUIT SAFETY ALERT warns respiratory professionals to use "only those heated-wire breathing circuits labeled for use with the specific humidifier being used." According to the July 14 alert, use of incompatible devices may result in the breathing circuits melting, which can cause "diminished gas delivery, fires, and patient and caregiver burns." FDA was alerted to the potential of melting heated-wire breathing circuits through a number of adverse event reports in its database, two reports of melting in the medical literature and studies conducted over the last year by the Center for Devices and Radiological Health's office of science and technology. FDA notes that "even when the electrical connectors for these heated-wire circuits are physically compatible, they may not be electrically compatible." Thus, "users should consult their biomedical engineering support group or the breathing circuit manufacturer" if they are in doubt as to the device's compatibility with the humidifier. FDA also warns that users should be certain that the heated- wire breathing circuit "has a recommended minute volume compatible with the ventilator settings." The agency notes that "operating above or below" minute volume limits "could result in melting." The agency reports that "in laboratory simulation tests conducted under low minute volume conditions, melting was observed primarily where the breathing circuit came into contact with another surface." FDA points out that "recommended minimum and maximum minute volumes are generally listed in the labeling of the humidifier unit or the heated-wire breathing circuit." Within recommended minute volumes, "surface contact has not been found to cause melting." Ventilator users can take further steps to prevent melting. FDA notes that "in actual practice, [melting] could occur if the device came into contact with a patient, bed rail, blanket, or piece of medical equipment." As an "extra precaution," FDA advises users not to "cover heated-wire breathing circuits with sheets, blankets, towels, clothing or other materials" or "rest the circuits on other surfaces." Rather, "users are advised to use a boom arm or tube-tree to support the breathing circuit."