The affected units were manufactured between January 2011 and April 2011.

The correction was made to notify customers that the device has an occlusion which prevents proper flow of the medical gases or oxygen resulting in insufficient oxygen (hypoxia or hypoxemia).

Vital Signs said this device may be included in its anesthesia circuits or sold separately.

The company said all affected HCH and Anesthesia Breathing Circuits with affected Hygroscopic Condenser Humidifiers are being replaced.