<prompt> Which of the following can delivery 100 oxygenVenturi maskAnesthetic face maskHudson maskNon - rebreather face mask  <response>: Devices used foroxygen therapy Performance of these devices can be described according to 1. Themaximum oxygen concentrationachievable to be delivered to the patient, and the reliability variability with which the devices do that. Looking at the reliability and variability of oxygen delivery to the patient we can divide these pieces of equipment intofixed performance or variable performance devices. This means that the achieved inspired oxygen concentration is either more dependent on thepatientspeak inspiratory flow rate PIFRvariableperformance devices or less so fixedperformance devices. Fixed performance devices These devices deliver a fixed inspired oxygen concentration to the patient, independent of the PIFR. Even at the time of PIFR no random entrainment of room air will occur to unpredictably alter the FiO2 with this equipment. Devices in this group include: SS Venturi mask Thereisentrainment of room air with these devices, but it is fixed and not dependent on the patients PIFR. Therefore the resulting delivered FiO2 is also constant. SS Non-rebreather facemask A reservoir bag supplies 100 oxygen and makes up for the deficit which occurs during times when the patients PIFR is higher than the oxygen supply flow to the mask usually around 20 Lmin from an oxygen wall or tank source. Aflap valveon the mask prevent or at least reduce entrainment of room air. These masks do not achieve a perfect seal with the patients face, sosomeroom air entrainment still occurs. FiO2 up to 70-80 can be achieved. SS Anesthetic facemaskwith an anesthetic breathing circuit These masks form a complete seal around the patients airway so no entrainment of room air can occur. The delivered oxygen concentration is the same as in the gas mixture supplied to the mask assuming no rebreathing occurs in the anesthetic breathing cicuit. We have also listed thePatil-Syracuseand theendoscopy maskunder this heading. Both of these devices allow instrumentation with a fiberoptic scope while maintaining a seal to the face with the mask. 2. Variable performance devices These devices deliver a variable inspired oxygen concentration to the patient, which depends on the PIFR. Depending on a patients inspiratory effo tidal volume, speed of inspiration and respiratory rate the PIFR can often exceed the flow rate at which oxygen or an oxygenair mixture is supplied by the device, meaning that at the time of PIFR more or less entrainment of room air occurs, altering the resulting FiO2 in an unpredictable fashion Devices in this group are: SS Nasal cannulas Simple facemask Hudson mask 