A pair of holographic lungs devised by Voyager's Doctor to keep Neelix breathing after Vidiians stole his own, requiring him to lie perfectly still inside a restraint in sickbay.
The holographic lungs are an improvised life-saving measure from the Voyager episode Phage. On a planetoid where the crew are searching for dilithium, Neelix is ambushed by two Vidiians, who use their combined weapon and surgical instrument to transport the lungs out of his chest for transplant into one of their own people.
Neelix has minutes to live and no compatible donor exists aboard. The Doctor realises that the sickbay holo-emitters, which let him handle solid matter, could equally project a working pair of lungs inside the patient's body. The catch is precision: the projection cannot follow movement, so Neelix must be held motionless in a restraining frame, possibly for the rest of his life, which brings on panic and despair.
The stolen organs cannot be returned, but the Vidiians help transplant one of Kes's lungs into Neelix, and the holographic set is switched off.