non-rebreather masks ( NRB , non-rebreather , non-rebreather facemask , etc.) are devices that used in medicine to assist in the delivery of oxygen therapy. NRB requires the patient to breathe unaided, but unlike the low nasal nasal cannula, NRB allows the delivery of higher oxygen concentrations.
Video Non-rebreather mask
Design
Non-rebreather mask covers the patient's nose and mouth and attaches by using an elastic strap around the patient's head. NRB has an enclosed reservoir pouch, typically 1 liter, which is connected to an external oxygen tank or Bulk Oxygen Supply system. Before NRB is placed in the patient, the reservoir bag is pumped into more than two thirds full of oxygen, at a rate of 15 liters per minute (lpm). About ¹/? the air from the reservoir is reduced when the patient inhales it, and is subsequently replaced by the flow from the supply of O 2 . If the sac becomes completely deflated, the patient will no longer have an air source to breathe.
The exhaled air is directed through a one-way valve in the mask, which prevents breathing room air and inhaling the exhaled air. The valve, together with sufficient seal around the patient's nose and mouth, permits the administration of high oxygen concentrations, about 60% - 80% O 2 . Many textbooks reported higher oxygen concentrations, but formal studies reporting these levels were not referred to the study. The patient should deflate some of the reservoir bags during inspiration or high oxygen concentration will not be achieved, and the mask will only provide the flow rate regulation of the liter in the flowmeter.
Ideally, a mask that can not refresh itself will not allow air from the surrounding environment to be inhaled. However, due to security concerns about anti-suffocation protection in the event of a failure of the gas source (ie completely drained oxygen cylinder), one of two one-way valves is usually removed, allowing inhalation of the outside air to a significant degree.. However, since almost all non-rebreathing masks can be removed, and produced in 1 adult size, most (from decades of clinical observation) do not provide a good seal with individual patient's face, allowing the entry of large amounts of ambient air resistance), and diluting the oxygen provided. Therefore, very few patients receive nearly 100% oxygen. The very high flow (& gt; = 30 LPM) of the oxygen flowmeter is required to partially overcome the room air dilution. Furthermore, the greater the patient's inspiratory flow rate, the greater the dilution of the air. Very little effort is required by most patients, to inspire at a flow rate of more than 50 LPM (readily visible in pulmonary function labs with routine spirometry tests).
The partial rebreather mask is designed to capture the first 150 ml of breath that is exhaled into the reservoir bag to inhale during the next breath. This part of the breath is initially sent at the end of the inhalation and is therefore sent to the anatomy of "deadspace" where gas exchange does not occur. Therefore, there will be no oxygen depletion or carbon dioxide recovery during the rebreathing component.
Maps Non-rebreather mask
Usage
Non-rebreather masks are used for patients with physical trauma, chronic airway constraints, cluster headaches, smoke inhalation, and carbon monoxide poisoning, or other patients requiring high-concentration oxygen, but do not require respiratory assistance. Uncomfortable patients with masks on their face, such as those with claustrophobia, or patients with oral injuries are more likely to benefit from nasal cannula, or "blow-by" oxygen. Self-breathing patients will require invasive or non-invasive mechanical ventilation.
See also
- Oxygen therapy
- Nasal kanula
- Mask valve pouch
References
Source of the article : Wikipedia
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