Philips Drops Advice to Stop Non-Pneumatic Nebulizer Use With Trilogy Evo Ventilators

Philips has changed its advice on using nebulizers with its Trilogy Evo Platform ventilators, and the US Food and Drug Administration has updated its recall notice to match. The May 28 update says "the recommendations provided below have changed and the reasons for recall below have been clarified."

The FDA first posted the notice on April 15. At that time, the recommendations told customers to "Stop all use of non-pneumatic nebulizers, including vibrating mesh nebulizers, with all Trilogy Evo Platform ventilators," as Respiratory Therapy reported on April 16.

The updated notice now reads: "Non-pneumatic nebulizers can be used as long as they are placed in accordance with the guidance and instructions on the proper location for a nebulizer on the various types of patient circuits." It adds a warning that ventilator accuracy "can be adversely affected by changes to the inspired gas caused by the use of both pneumatic and non-pneumatic nebulizers."

What changed and what did not

Philips sent customers a letter on March 2 and a follow-up letter on April 24 with updated guidance on nebulizer use, according to the FDA. The core action is unchanged: update all Trilogy Evo Platform ventilators to software version 1.05.15.00 and review the latest User Manual Addendum. The FDA said the software is available as a free download through Philips' MyP4P and InCenter websites. For customers who have installed that release, the user interface refers only to pneumatic nebulizers, but the instructions also apply to non-pneumatic ones, the notice says.

The correction covers the Trilogy Evo, Trilogy EV300, Trilogy Evo O2 and Trilogy Evo Universal. It involves correcting devices rather than removing them, and the FDA identifies it as the most serious type of recall. As of March 6, Philips had reported three serious injuries and no deaths associated with the issues, the agency said.

Three issues

The FDA lists three problems. First, nebulizers, pneumatic or non-pneumatic, may affect ventilator performance depending on the nebulizer type, circuit configuration and therapy mode. When a nebulizer is used inline with a passive circuit in AC-VC, SIMV or AVAPS modes, displayed volume and flow may not reflect actual patient values. The notice says non-pneumatic nebulizers have not shown an impact on performance in adult active PAP and adult dual-limb circuits based on available testing, while pneumatic nebulizers may affect performance across all circuit types.

Second, aerosol that enters the ventilator can build up on the internal flow sensor, which the FDA said may cause over-delivery of tidal volume, under-delivery of oxygen and, in some cases, a Ventilatory Inoperative condition; affected sensors should be replaced. Third, the obstruction alarm sometimes fails to trigger within the two breath cycles or five seconds required by the relevant standards, and in certain modes could be delayed by up to four breaths.

The ventilators provide continuous and intermittent positive airway pressure support for patients weighing at least 2.5 kg, in hospitals, other care settings and nonemergency transport; the Trilogy EV300 and Trilogy Evo may also be used at home, according to the FDA.