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16:02:58 or the physics behind this? When you have a gas16:03:01 source go through a small capillary tube, you have16:03:05 a high velocity right here at this outlet. There16:03:09 is one or two capillary tubes that go down into a 716:03:12 reservoir. There's something called Bernouilli's16:03:15 law. When you have a high gas source going16:03:18 through an opening, there's a decreased pressure16:03:20 right there. That causes the liquid to be sucked16:03:23 up through this capillary tube and then there are16:03:26 shearing forces on the surface of that liquid that16:03:31 turn this into various particles of different16:03:34 sizes.16:03:3516:03:35 What is not shown in these schematics or these16:03:38 nebulizers is there are a series of baffles here.16:03:40 There's a huge spread of particles that were just16:03:44 developed when we turned on the compressor. They16:03:47 range in size from .1 to 30 microns. Obviously,16:03:52 30 microns is a huge size. Inertial impaction,16:03:56 which we talked about earlier in the airways, that16:03:58 occurs in the nebulizers, also. Those larger16:04:01 particles impact against baffles in there. They16:04:06 rain back down to the reservoir and they get16:04:08 re‐nebulized over and over and over again. That16:04:10 is the fate of 99% of the particles. So only 1%16:04:15 of the particles actually are output to the16:04:18 patient.
16:04:1816:04:20 This is something called the mainstream nebulizer.16:04:23 Over here is something called the side stream16:04:25 nebulizer. That's actually a brand of nebulizer,16:04:28 and that's because the capillary tube comes in16:04:30 alongside the compressed gas source. You're16:04:34 sheering across a larger volume with this16:04:38 cross‐section here, compared to this here. So16:04:41 these, in some ways, can be more efficient.16:04:4316:04:45 The problem is all nebulizers were not created16:04:49 equal. This was a study done at National Jewish16:04:53 Hospital in 1994. Each one of these numbers here16:04:56 has a different grand of a nebulizer. There's 1716:05:00 available brands in the U.S. when they did this16:05:02 study. This shows time of nebulization to the16:05:07 point of eight‐fold decline in particle output.16:05:10 The diamonds are the 95% confidence intervals.16:05:14 The horizontal line is the mean. And each one of16:05:17 these boxes is the average determination of16:05:21 triplicate treatments with four different16:05:24 nebulizers, but of the same brand. So they had16:05:27 four nebulizers produced by the same company. For16:05:30 example, number two here is the Acorn They took16:05:33 four Acorn nebulizers. What's interesting is16:05:38 these three boxes here are together, but this one16:05:41 right here is quite different from those three, so 8
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