> I never understood why they went out of fashion. They are very large, very heavy, and completely obstruct physical access to the patient, and the patient's a

> I never understood why they went out of fashion. They are very large, very heavy, and completely obstruct physical access to the patient, and the patient's access to anything outside the lung. All this doesn't make them useless, or even obsolete, but it seems obvious why something more convenient may be desired.