Which of the following can delivery 100% oxygen
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 thepatient'speak inspiratory flow rate (PIFR)(variableperformance 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 patient's 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 patient's PIFR is higher than the oxygen supply flow to the mask (usually around 20 L/min 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 patient's face, sosomeroom air entrainment still occurs. FiO2 up to 70-80% can be achieved. SS Anesthetic facemask(with an anesthetic breathing circuit) These masks form a complete seal around the patient's 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 patient's inspiratory effo (tidal volume, 'speed' of inspiration and respiratory rate) the PIFR can often exceed the flow rate at which oxygen or an oxygen/air 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
Venturi mask
Anesthetic face mask
Hudson mask
Non - rebreather face mask
Airway