Mardimae Alexandra, Slessarev Marat, Han Jay, Sasano Hiroshi, Sasano Nobuko, Azami Takafumi, Fedorko Ludwik, Savage Tim, Fowler Rob, Fisher Joseph A
Department of Anesthesiology, University Health Network, Toronto, Ontario, Canada.
Ann Emerg Med. 2006 Oct;48(4):391-9, 399.e1-2. doi: 10.1016/j.annemergmed.2006.06.039.
In a pandemic, hypoxic patients will require an effective oxygen (O2) delivery mask that protects them from inhaling aerosolized particles produced by others, as well as protecting the health care provider from exposure from the patient. We modified an existing N95 mask to optimize O2 supplementation while maintaining respiratory isolation.
An N95 mask was modified to deliver O2 by inserting a plastic manifold consisting of a 1-way inspiratory valve, an O2 inlet and a gas reservoir. In a prospective repeated-measures study, we studied 10 healthy volunteers in each of 3 phases, investigating (1) the fractional inspiratory concentrations of O2 (F(I)O2) delivered by the N95 O2 mask, the Hi-Ox80 O2 mask, and the nonrebreathing mask during resting ventilation and hyperventilation, each at 3 O2 flow rates; (2) the ability of the N95 mask, the N95 O2 mask, and the nonrebreathing mask to filter microparticles from ambient air; and (3) to contain microparticles generated inside the mask.
The F(I)O2s (median [range]) delivered by the Hi-Ox80 O2 mask, the N95 O2 mask, and the nonrebreathing mask during resting ventilation, at 8 L/minute O2 flow, were 0.90 (0.79 to 0.96), 0.68 (0.60 to 0.85), and 0.59 (0.52 to 0.68), respectively. During hyperventilation, the FiO2s of all 3 masks were clinically equivalent. The N95 O2 mask, but not the nonrebreathing mask, provided the same efficiency of filtration of internal and external particles as the original N95, regardless of O2 flow into the mask.
An N95 mask can be modified to administer a clinically equivalent FiO2 to a nonrebreathing mask while maintaining its filtration and isolation capabilities.
在大流行期间，缺氧患者将需要一种有效的氧气（O₂）输送面罩，既能保护他们不吸入他人产生的气溶胶颗粒，又能保护医护人员不被患者感染。我们对现有的N95口罩进行了改良，以优化氧气补充，同时保持呼吸隔离。
通过插入一个由单向吸气阀、氧气入口和储气罐组成的塑料歧管，对N95口罩进行改造以输送氧气。在一项前瞻性重复测量研究中，我们在3个阶段分别对10名健康志愿者进行了研究，调查（1）N95氧气面罩、Hi-Ox80氧气面罩和非重复呼吸面罩在静息通气和过度通气时，在3种氧气流速下输送的吸入氧分数（F(I)O₂）；（2）N95口罩、N95氧气面罩和非重复呼吸面罩从周围空气中过滤微粒的能力；（3）口罩内部产生的微粒的容纳情况。
在静息通气时，氧气流速为8升/分钟时，Hi-Ox80氧气面罩、N95氧气面罩和非重复呼吸面罩输送的F(I)O₂（中位数[范围]）分别为0.90（0.79至0.96）、0.68（0.60至0.85）和0.59（0.52至0.68）。在过度通气时，所有3种面罩的FiO₂在临床上相当。无论氧气流入面罩的情况如何，N95氧气面罩而非非重复呼吸面罩，提供了与原始N95相同的内部和外部颗粒过滤效率。
可以对N95口罩进行改造，以提供与非重复呼吸面罩临床上相当的FiO₂，同时保持其过滤和隔离能力。
