Thank you for allowing us to respond to the Letter to the Editor, “With Technology Comes Responsibility: Intraoperative Failure of an Anesthetic Vaporizer.”1
Datex-Ohmeda would like to compliment the author for correctly identifying the underlying cause of this particular failure. Indeed, the original design of the D-Tec Plus, with it's improved alarm handling and logging software, does sense differences between the inlet and outlet ports of the vaporizer. This feature was included to prevent any backward flow through the vaporizer, which can significantly alter the function of the vaporizer.
The D-Tec Plus is a variant of the Datex-Ohmeda Tec 6 Plus desflurane vaporizer, designed specifically for use with Dräger anesthesia machines. Before the release of the new design, Datex-Ohmeda provided the D-Tec Plus to Dräger Medical so that the vaporizer could be validated on Dräger designed and manufactured anesthesia machines. The effect of the pulsating flows that occur during volume mode ventilation in the Julian design was not recognized during this validation.
After notification of the events described in the Letter to the Editor, Datex-Ohmeda, along with Dräger, worked quickly to fully understand the implications of this pulsating fresh gas flow and its impact upon the alarm management of the D-Tec Plus. As a result of this investigation, the D-Tec Plus software has been upgraded. This upgrade has been provided to all the D-Tec Plus vaporizers in use and is currently being used during the manufacture of all new D-Tec Plus vaporizers.