[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:01.74,Default,,0000,0000,0000,,
Dialogue: 0,0:00:01.74,0:00:04.61,Default,,0000,0000,0000,,Now let's say that you\Nhave a vial of plasma.
Dialogue: 0,0:00:04.61,0:00:06.95,Default,,0000,0000,0000,,And I'm actually going\Nto label it as we go.
Dialogue: 0,0:00:06.95,0:00:11.50,Default,,0000,0000,0000,,We've got some sodium\Nfloating in here
Dialogue: 0,0:00:11.50,0:00:15.27,Default,,0000,0000,0000,,and you've got some anion\Nin purple over here.
Dialogue: 0,0:00:15.27,0:00:19.29,Default,,0000,0000,0000,,And this could be anything\Nthat really binds to sodium.
Dialogue: 0,0:00:19.29,0:00:23.20,Default,,0000,0000,0000,,So if this is some negatively\Ncharged ion, maybe chloride,
Dialogue: 0,0:00:23.20,0:00:26.90,Default,,0000,0000,0000,,or bicarb, those are\Nthe two most common.
Dialogue: 0,0:00:26.90,0:00:31.54,Default,,0000,0000,0000,,And you've also got, let's\Nsay, some glucose in here.
Dialogue: 0,0:00:31.54,0:00:40.61,Default,,0000,0000,0000,,And maybe some urea, or we\Ncall it urea nitrogen as well.
Dialogue: 0,0:00:40.61,0:00:42.94,Default,,0000,0000,0000,,So you've got a few things\Nfloating around the plasma
Dialogue: 0,0:00:42.94,0:00:44.55,Default,,0000,0000,0000,,and someone asks\Nyou, well, what is
Dialogue: 0,0:00:44.55,0:00:47.89,Default,,0000,0000,0000,,the total osmolarity\Nof the plasma?
Dialogue: 0,0:00:47.89,0:00:49.67,Default,,0000,0000,0000,,And you know that\Nthis is in units
Dialogue: 0,0:00:49.67,0:00:56.29,Default,,0000,0000,0000,,of osmoles per liter\Nblood, Actually,
Dialogue: 0,0:00:56.29,0:00:59.77,Default,,0000,0000,0000,,I should write liter\Nplasma to be more accurate.
Dialogue: 0,0:00:59.77,0:01:02.45,Default,,0000,0000,0000,,Since that's what we're\Ntalking about here.
Dialogue: 0,0:01:02.45,0:01:06.48,Default,,0000,0000,0000,,So per one liter of plasma.
Dialogue: 0,0:01:06.48,0:01:08.60,Default,,0000,0000,0000,,And these are the units\Nthat we have to think about
Dialogue: 0,0:01:08.60,0:01:10.26,Default,,0000,0000,0000,,to answer this\Nquestion, is, what
Dialogue: 0,0:01:10.26,0:01:13.40,Default,,0000,0000,0000,,are the osmoles per\Nliter of plasma?
Dialogue: 0,0:01:13.40,0:01:14.65,Default,,0000,0000,0000,,So let's go through this.
Dialogue: 0,0:01:14.65,0:01:16.36,Default,,0000,0000,0000,,And I'm going to give\Nyou some lab values
Dialogue: 0,0:01:16.36,0:01:19.30,Default,,0000,0000,0000,,and we'll see how based on just\Na few lab values and really
Dialogue: 0,0:01:19.30,0:01:23.29,Default,,0000,0000,0000,,just four of the most\Nrepresentative solutes,
Dialogue: 0,0:01:23.29,0:01:25.55,Default,,0000,0000,0000,,or most important\Nsolutes, we can
Dialogue: 0,0:01:25.55,0:01:29.00,Default,,0000,0000,0000,,get a pretty close\Nguesstimate of the osmolarity.
Dialogue: 0,0:01:29.00,0:01:32.24,Default,,0000,0000,0000,,So you don't actually need to\Nknow every single osmole that's
Dialogue: 0,0:01:32.24,0:01:32.87,Default,,0000,0000,0000,,in your plasma.
Dialogue: 0,0:01:32.87,0:01:34.40,Default,,0000,0000,0000,,You can figure it\Nout based on four
Dialogue: 0,0:01:34.40,0:01:35.60,Default,,0000,0000,0000,,of the most important ones.
Dialogue: 0,0:01:35.60,0:01:37.82,Default,,0000,0000,0000,,So let's go with the\Nfirst one, sodium.
Dialogue: 0,0:01:37.82,0:01:40.93,Default,,0000,0000,0000,,
Dialogue: 0,0:01:40.93,0:01:43.60,Default,,0000,0000,0000,,And let's say the lab tells\Nyou, well, your sodium value--
Dialogue: 0,0:01:43.60,0:01:47.28,Default,,0000,0000,0000,,and I'm going to write the labs\Nin kind of this grey color,
Dialogue: 0,0:01:47.28,0:01:49.63,Default,,0000,0000,0000,,somehow that reminds\Nme of the lab--
Dialogue: 0,0:01:49.63,0:01:52.58,Default,,0000,0000,0000,,let's say they say the sodium\Nvalue is 140 milliequivalents
Dialogue: 0,0:01:52.58,0:01:53.92,Default,,0000,0000,0000,,per liter.
Dialogue: 0,0:01:53.92,0:01:57.68,Default,,0000,0000,0000,,So how do you take that and\Nmake it into osmoles per liter?
Dialogue: 0,0:01:57.68,0:02:00.32,Default,,0000,0000,0000,,Well, our denominator\Nis already OK.
Dialogue: 0,0:02:00.32,0:02:04.96,Default,,0000,0000,0000,,But immediately, you can\Nsay, OK, well 140 millimoles
Dialogue: 0,0:02:04.96,0:02:07.63,Default,,0000,0000,0000,,per liter is what that equals.
Dialogue: 0,0:02:07.63,0:02:10.21,Default,,0000,0000,0000,,And you know that because\Nsodium is a monovalent.
Dialogue: 0,0:02:10.21,0:02:11.68,Default,,0000,0000,0000,,It's only got one charge.
Dialogue: 0,0:02:11.68,0:02:14.51,Default,,0000,0000,0000,,
Dialogue: 0,0:02:14.51,0:02:16.44,Default,,0000,0000,0000,,If it's monovalent,\Nthen that means
Dialogue: 0,0:02:16.44,0:02:19.55,Default,,0000,0000,0000,,that the equivalents\Nequal the moles.
Dialogue: 0,0:02:19.55,0:02:20.92,Default,,0000,0000,0000,,And now that you're\Nin moles, you
Dialogue: 0,0:02:20.92,0:02:22.92,Default,,0000,0000,0000,,can actually go\Nacross to osmoles.
Dialogue: 0,0:02:22.92,0:02:28.04,Default,,0000,0000,0000,,You could say 140 osmoles\Nor milliosmoles per liter.
Dialogue: 0,0:02:28.04,0:02:31.90,Default,,0000,0000,0000,,And you know that because\Nonce sodium is in water,
Dialogue: 0,0:02:31.90,0:02:34.42,Default,,0000,0000,0000,,it acts the same way that\Nyou would expect it to act.
Dialogue: 0,0:02:34.42,0:02:36.40,Default,,0000,0000,0000,,It doesn't split\Nup or anything like
Dialogue: 0,0:02:36.40,0:02:38.85,Default,,0000,0000,0000,,that because it's one particle.
Dialogue: 0,0:02:38.85,0:02:42.48,Default,,0000,0000,0000,,So it acts as a single particle.
Dialogue: 0,0:02:42.48,0:02:43.88,Default,,0000,0000,0000,,One particle.
Dialogue: 0,0:02:43.88,0:02:45.85,Default,,0000,0000,0000,,So if it's one\Nparticle, it's going
Dialogue: 0,0:02:45.85,0:02:49.12,Default,,0000,0000,0000,,to have 140\Nmilliosmoles per liter.
Dialogue: 0,0:02:49.12,0:02:53.31,Default,,0000,0000,0000,,And we've effectively gotten one\Nquarter of this problem done.
Dialogue: 0,0:02:53.31,0:02:57.39,Default,,0000,0000,0000,,Because all we need to do is\Ntake the four different solutes
Dialogue: 0,0:02:57.39,0:02:59.99,Default,,0000,0000,0000,,that we've identified\Nand add them up together.
Dialogue: 0,0:02:59.99,0:03:01.74,Default,,0000,0000,0000,,So we've figured out sodium.
Dialogue: 0,0:03:01.74,0:03:04.41,Default,,0000,0000,0000,,And now let's move\Non to the anion.
Dialogue: 0,0:03:04.41,0:03:08.10,Default,,0000,0000,0000,,And the trick to the anion is\Njust thinking of it as sodium.
Dialogue: 0,0:03:08.10,0:03:10.58,Default,,0000,0000,0000,,It's almost the same as\Nsodium, but just the reverse.
Dialogue: 0,0:03:10.58,0:03:13.26,Default,,0000,0000,0000,,So we know that it's\Ngoing to be 140.
Dialogue: 0,0:03:13.26,0:03:17.32,Default,,0000,0000,0000,,We're going to use 140\Nas the number here.
Dialogue: 0,0:03:17.32,0:03:24.02,Default,,0000,0000,0000,,Because our assumption is that\Nsodium is a positive charge
Dialogue: 0,0:03:24.02,0:03:25.52,Default,,0000,0000,0000,,and for every one\Npositive charge,
Dialogue: 0,0:03:25.52,0:03:27.44,Default,,0000,0000,0000,,you need one negative charge.
Dialogue: 0,0:03:27.44,0:03:30.19,Default,,0000,0000,0000,,So we're going to assume that\Nall the negative charges are
Dialogue: 0,0:03:30.19,0:03:31.49,Default,,0000,0000,0000,,coming from these anions.
Dialogue: 0,0:03:31.49,0:03:33.40,Default,,0000,0000,0000,,And these would be\Nthings like we said,
Dialogue: 0,0:03:33.40,0:03:37.24,Default,,0000,0000,0000,,things like chloride or\Nbicarb, something like that.
Dialogue: 0,0:03:37.24,0:03:39.11,Default,,0000,0000,0000,,So again, we don't\Nactually get these numbers
Dialogue: 0,0:03:39.11,0:03:41.00,Default,,0000,0000,0000,,or even need these\Nnumbers, we simply
Dialogue: 0,0:03:41.00,0:03:45.20,Default,,0000,0000,0000,,take that 140 and\Nwe multiply by 2
Dialogue: 0,0:03:45.20,0:03:48.88,Default,,0000,0000,0000,,and assume that the other half\Nis going to be some anion.
Dialogue: 0,0:03:48.88,0:03:51.26,Default,,0000,0000,0000,,Now we actually have\Nto convert units still.
Dialogue: 0,0:03:51.26,0:03:56.40,Default,,0000,0000,0000,,We have to get over to\Nmilliosmoles per liter.
Dialogue: 0,0:03:56.40,0:03:58.91,Default,,0000,0000,0000,,And so we know that the anion\Nis going to be monovalent
Dialogue: 0,0:03:58.91,0:04:02.37,Default,,0000,0000,0000,,and that gets us to millimoles.
Dialogue: 0,0:04:02.37,0:04:04.34,Default,,0000,0000,0000,,And we use the same\Nlogic as above.
Dialogue: 0,0:04:04.34,0:04:06.92,Default,,0000,0000,0000,,We just say, OK, well\Nif that was millimoles
Dialogue: 0,0:04:06.92,0:04:11.31,Default,,0000,0000,0000,,and it's still one particle,\Nmeaning it's not splitting up
Dialogue: 0,0:04:11.31,0:04:14.23,Default,,0000,0000,0000,,when it hits water and going\Nin two different directions,
Dialogue: 0,0:04:14.23,0:04:19.55,Default,,0000,0000,0000,,in a sense, having\Ntwice the effect,
Dialogue: 0,0:04:19.55,0:04:22.77,Default,,0000,0000,0000,,we're going to end up with\N140 milliosmoles per liter,
Dialogue: 0,0:04:22.77,0:04:24.22,Default,,0000,0000,0000,,just as before.
Dialogue: 0,0:04:24.22,0:04:26.84,Default,,0000,0000,0000,,So this is our second\Npart done, right?
Dialogue: 0,0:04:26.84,0:04:28.02,Default,,0000,0000,0000,,So two parts are done.
Dialogue: 0,0:04:28.02,0:04:31.36,Default,,0000,0000,0000,,We figured out the sodium\Nand we figured out the anion.
Dialogue: 0,0:04:31.36,0:04:33.15,Default,,0000,0000,0000,,Now let's go over to glucose.
Dialogue: 0,0:04:33.15,0:04:36.90,Default,,0000,0000,0000,,So let's figure out how to\Nget glucose as units from what
Dialogue: 0,0:04:36.90,0:04:39.28,Default,,0000,0000,0000,,the lab gives us, which I'll\Ntell you in just a second,
Dialogue: 0,0:04:39.28,0:04:41.25,Default,,0000,0000,0000,,into something more usable.
Dialogue: 0,0:04:41.25,0:04:45.67,Default,,0000,0000,0000,,So how do we actually get\Nover to something usable?
Dialogue: 0,0:04:45.67,0:04:51.06,Default,,0000,0000,0000,,Let me actually, switch over.
Dialogue: 0,0:04:51.06,0:04:52.37,Default,,0000,0000,0000,,There we go.
Dialogue: 0,0:04:52.37,0:04:53.67,Default,,0000,0000,0000,,Make some space on our canvas.
Dialogue: 0,0:04:53.67,0:04:58.17,Default,,0000,0000,0000,,So let's say we have\Nour glucose here.
Dialogue: 0,0:04:58.17,0:05:00.83,Default,,0000,0000,0000,,And the lab calls us\Nand says, hey, we just
Dialogue: 0,0:05:00.83,0:05:05.61,Default,,0000,0000,0000,,got your lab result, it was\N90 milligrams per deciliter.
Dialogue: 0,0:05:05.61,0:05:08.58,Default,,0000,0000,0000,,It's actually a very,\Nvery common lab value
Dialogue: 0,0:05:08.58,0:05:12.59,Default,,0000,0000,0000,,or common range for\Na glucose lab value.
Dialogue: 0,0:05:12.59,0:05:14.02,Default,,0000,0000,0000,,One thing we have\Nto do right away
Dialogue: 0,0:05:14.02,0:05:17.33,Default,,0000,0000,0000,,is figure out how to get\Nfrom milligrams to moles.
Dialogue: 0,0:05:17.33,0:05:20.42,Default,,0000,0000,0000,,And you know that this is\Nwhat glucose looks like.
Dialogue: 0,0:05:20.42,0:05:22.42,Default,,0000,0000,0000,,This is the formula for it.
Dialogue: 0,0:05:22.42,0:05:25.86,Default,,0000,0000,0000,,So to get the overall\Nweight, the atomic weight,
Dialogue: 0,0:05:25.86,0:05:27.60,Default,,0000,0000,0000,,you could say,\Nwell, let's take 6,
Dialogue: 0,0:05:27.60,0:05:29.58,Default,,0000,0000,0000,,because that's how\Nmany carbons we have,
Dialogue: 0,0:05:29.58,0:05:32.28,Default,,0000,0000,0000,,times the weight of\Ncarbon, which is 12,
Dialogue: 0,0:05:32.28,0:05:35.59,Default,,0000,0000,0000,,plus 12, because that's\Nwhat we have here,
Dialogue: 0,0:05:35.59,0:05:38.39,Default,,0000,0000,0000,,times the weight of\Nhydrogen, which is 1,
Dialogue: 0,0:05:38.39,0:05:43.59,Default,,0000,0000,0000,,plus 6, times the\Nweight of oxygen.
Dialogue: 0,0:05:43.59,0:05:47.29,Default,,0000,0000,0000,,And that's going to equal--\Nthis is 72, this is 12,
Dialogue: 0,0:05:47.29,0:05:56.74,Default,,0000,0000,0000,,and this is 96, and add them all\Nup together, and we get-- 180.
Dialogue: 0,0:05:56.74,0:06:01.32,Default,,0000,0000,0000,,So we have 180 atomic mass\Nunits per glucose molecule.
Dialogue: 0,0:06:01.32,0:06:03.19,Default,,0000,0000,0000,,Which means, if you\Nthink back, which
Dialogue: 0,0:06:03.19,0:06:13.51,Default,,0000,0000,0000,,means that one mole of\Nglucose equals 180 grams.
Dialogue: 0,0:06:13.51,0:06:15.81,Default,,0000,0000,0000,,And since these\Nare way, way bigger
Dialogue: 0,0:06:15.81,0:06:18.39,Default,,0000,0000,0000,,than, I mean this is grams, and\Nwe're talking about milligrams
Dialogue: 0,0:06:18.39,0:06:22.92,Default,,0000,0000,0000,,over here, so I'm going to\Njust switch it down by 1,000.
Dialogue: 0,0:06:22.92,0:06:31.16,Default,,0000,0000,0000,,So one millimole of glucose\Nequals 180 milligrams.
Dialogue: 0,0:06:31.16,0:06:33.40,Default,,0000,0000,0000,,All I did was divide by 1,000.
Dialogue: 0,0:06:33.40,0:06:37.43,Default,,0000,0000,0000,,So now I can take this unit and\Nactually use our conversions.
Dialogue: 0,0:06:37.43,0:06:41.24,Default,,0000,0000,0000,,I could say, well, let's\Nmultiply that by 100
Dialogue: 0,0:06:41.24,0:06:45.13,Default,,0000,0000,0000,,and-- let's say, one\Nmillimole rather,
Dialogue: 0,0:06:45.13,0:06:50.44,Default,,0000,0000,0000,,one millimole per 180\Nmilligrams, that'll
Dialogue: 0,0:06:50.44,0:06:52.36,Default,,0000,0000,0000,,cancel the milligrams out.
Dialogue: 0,0:06:52.36,0:06:55.22,Default,,0000,0000,0000,,And I also have to get from\Ndeciliters to liters, right?
Dialogue: 0,0:06:55.22,0:06:59.93,Default,,0000,0000,0000,,So I've got to go 10\Ndeciliters equals 1 liter.
Dialogue: 0,0:06:59.93,0:07:02.31,Default,,0000,0000,0000,,And that'll cancel\Nmy deciliters out.
Dialogue: 0,0:07:02.31,0:07:06.18,Default,,0000,0000,0000,,So I'm left with-- and this\N10 will get rid of that 0--
Dialogue: 0,0:07:06.18,0:07:08.42,Default,,0000,0000,0000,,so I'm left with\N90 divided by 18,
Dialogue: 0,0:07:08.42,0:07:13.74,Default,,0000,0000,0000,,which is 5 millimoles per liter.
Dialogue: 0,0:07:13.74,0:07:16.55,Default,,0000,0000,0000,,And, just as above, I\Nknow that the glucose
Dialogue: 0,0:07:16.55,0:07:20.68,Default,,0000,0000,0000,,will behave as one particle\Nin water, in solution.
Dialogue: 0,0:07:20.68,0:07:25.77,Default,,0000,0000,0000,,So it's going to be 5 osmoles,\Nor milliosmoles, actually.
Dialogue: 0,0:07:25.77,0:07:30.20,Default,,0000,0000,0000,,5 milliosmoles per liter.
Dialogue: 0,0:07:30.20,0:07:32.04,Default,,0000,0000,0000,,And that's the\Nright units, right?
Dialogue: 0,0:07:32.04,0:07:36.27,Default,,0000,0000,0000,,So I figured out another\Npart of my formula.
Dialogue: 0,0:07:36.27,0:07:38.77,Default,,0000,0000,0000,,And I'll show you the actual\Nformula at the end of this,
Dialogue: 0,0:07:38.77,0:07:40.73,Default,,0000,0000,0000,,but I wanted to work\Nthrough it piece by piece.
Dialogue: 0,0:07:40.73,0:07:45.34,Default,,0000,0000,0000,,So we've done glucose now and\Nwe're ready for our last bit,
Dialogue: 0,0:07:45.34,0:07:50.20,Default,,0000,0000,0000,,so let's do our last one,\Nwhich is going to be urea.
Dialogue: 0,0:07:50.20,0:07:54.23,Default,,0000,0000,0000,,Specifically, the lab is not\Ngoing to call us about urea,
Dialogue: 0,0:07:54.23,0:07:58.03,Default,,0000,0000,0000,,it's going to call us\Nabout blood urea nitrogen.
Dialogue: 0,0:07:58.03,0:08:00.67,Default,,0000,0000,0000,,And actually, it\Nmatters what this means.
Dialogue: 0,0:08:00.67,0:08:03.66,Default,,0000,0000,0000,,So what that exactly\Nmeans is that they're
Dialogue: 0,0:08:03.66,0:08:08.20,Default,,0000,0000,0000,,measuring the nitrogen\Ncomponent of urea.
Dialogue: 0,0:08:08.20,0:08:11.14,Default,,0000,0000,0000,,And so they'll call you and\Nsay, well, we measured it
Dialogue: 0,0:08:11.14,0:08:16.56,Default,,0000,0000,0000,,and the value came to 14\Nmilligrams per deciliter.
Dialogue: 0,0:08:16.56,0:08:18.34,Default,,0000,0000,0000,,Something like\Nthat, so let's say
Dialogue: 0,0:08:18.34,0:08:20.24,Default,,0000,0000,0000,,that's the amount\Nof urea we find
Dialogue: 0,0:08:20.24,0:08:22.55,Default,,0000,0000,0000,,in our little tube of plasma.
Dialogue: 0,0:08:22.55,0:08:26.09,Default,,0000,0000,0000,,How do we convert that to moles\Nper liter like we did before?
Dialogue: 0,0:08:26.09,0:08:32.53,Default,,0000,0000,0000,,Well, again, it'll be helpful if\NI draw out a molecule of urea.
Dialogue: 0,0:08:32.53,0:08:34.36,Default,,0000,0000,0000,,So we have something like this.
Dialogue: 0,0:08:34.36,0:08:36.33,Default,,0000,0000,0000,,A couple nitrogens.
Dialogue: 0,0:08:36.33,0:08:37.94,Default,,0000,0000,0000,,And this is what\Nurea looks like.
Dialogue: 0,0:08:37.94,0:08:39.16,Default,,0000,0000,0000,,It's a pretty small molecule.
Dialogue: 0,0:08:39.16,0:08:42.14,Default,,0000,0000,0000,,A couple nitrogens,\Ncarbon, and oxygen.
Dialogue: 0,0:08:42.14,0:08:46.49,Default,,0000,0000,0000,,And these nitrogens have an\Natomic mass unit of 14 apiece.
Dialogue: 0,0:08:46.49,0:08:48.30,Default,,0000,0000,0000,,So that's 14.
Dialogue: 0,0:08:48.30,0:08:51.44,Default,,0000,0000,0000,,And this is 14\Nover here, as well.
Dialogue: 0,0:08:51.44,0:08:56.66,Default,,0000,0000,0000,,So what the lab actually\Nmeasures is just this part.
Dialogue: 0,0:08:56.66,0:08:58.41,Default,,0000,0000,0000,,It's just measuring\Nthe two nitrogens.
Dialogue: 0,0:08:58.41,0:09:01.32,Default,,0000,0000,0000,,It's not measuring the weight\Nof the entire molecule.
Dialogue: 0,0:09:01.32,0:09:03.82,Default,,0000,0000,0000,,So all it's going to give you\Nis the weight of the nitrogens
Dialogue: 0,0:09:03.82,0:09:06.50,Default,,0000,0000,0000,,that are in the molecule.
Dialogue: 0,0:09:06.50,0:09:11.00,Default,,0000,0000,0000,,So what that means is that we\Nsay, OK, well, that tells us
Dialogue: 0,0:09:11.00,0:09:22.43,Default,,0000,0000,0000,,that one molecule of urea is\Ngoing to be 28 atomic mass
Dialogue: 0,0:09:22.43,0:09:28.45,Default,,0000,0000,0000,,units of-- I'm going to put\Nit in quotes-- urea nitrogen.
Dialogue: 0,0:09:28.45,0:09:32.03,Default,,0000,0000,0000,,Because that's the part of\Nurea that we're measuring
Dialogue: 0,0:09:32.03,0:09:36.04,Default,,0000,0000,0000,,and that means that\None mole of urea
Dialogue: 0,0:09:36.04,0:09:44.25,Default,,0000,0000,0000,,is going to be 28\Ngrams of urea nitrogen.
Dialogue: 0,0:09:44.25,0:09:47.95,Default,,0000,0000,0000,,And because, again,\Nthis is much, much more
Dialogue: 0,0:09:47.95,0:09:50.26,Default,,0000,0000,0000,,than what we actually have,\Nlet me divide by 1,000.
Dialogue: 0,0:09:50.26,0:09:56.86,Default,,0000,0000,0000,,So one millimole equals 28\Nmilligrams of urea nitrogen.
Dialogue: 0,0:09:56.86,0:10:02.36,Default,,0000,0000,0000,,So that's how we figure\Nout the conversion.
Dialogue: 0,0:10:02.36,0:10:04.24,Default,,0000,0000,0000,,And I do the exact\Nsame thing as above.
Dialogue: 0,0:10:04.24,0:10:06.42,Default,,0000,0000,0000,,I say, OK, well, let's\Ntimes-- let's say,
Dialogue: 0,0:10:06.42,0:10:08.21,Default,,0000,0000,0000,,I want to get rid of\Nthe milligrams, right?
Dialogue: 0,0:10:08.21,0:10:14.79,Default,,0000,0000,0000,,So 1 millimole divided\Nby 28 milligrams,
Dialogue: 0,0:10:14.79,0:10:17.09,Default,,0000,0000,0000,,and that'll get rid\Nof my milligrams.
Dialogue: 0,0:10:17.09,0:10:22.62,Default,,0000,0000,0000,,And I'll take, let's say,\N10 deciliters over 1 liter
Dialogue: 0,0:10:22.62,0:10:25.55,Default,,0000,0000,0000,,and that'll help me get\Nrid of my deciliters.
Dialogue: 0,0:10:25.55,0:10:31.47,Default,,0000,0000,0000,,And so then I'm left with\N14 over 28, which is 0.5.
Dialogue: 0,0:10:31.47,0:10:34.40,Default,,0000,0000,0000,,And then times 10, so that's 5.
Dialogue: 0,0:10:34.40,0:10:39.38,Default,,0000,0000,0000,,5 millimoles per liter.
Dialogue: 0,0:10:39.38,0:10:41.87,Default,,0000,0000,0000,,And as I've done\Na couple times now
Dialogue: 0,0:10:41.87,0:10:44.17,Default,,0000,0000,0000,,and we know that it's\Nthe urea nitrogen
Dialogue: 0,0:10:44.17,0:10:47.88,Default,,0000,0000,0000,,or the urea is going to act and\Nbehave like one molecule or one
Dialogue: 0,0:10:47.88,0:10:49.42,Default,,0000,0000,0000,,particle when it's\Nin water, it's
Dialogue: 0,0:10:49.42,0:10:51.76,Default,,0000,0000,0000,,not going to split up\Nor anything like that,
Dialogue: 0,0:10:51.76,0:10:53.51,Default,,0000,0000,0000,,so that means that\Nit's going to basically
Dialogue: 0,0:10:53.51,0:10:58.54,Default,,0000,0000,0000,,be 5 milliosmoles per liter.
Dialogue: 0,0:10:58.54,0:11:01.67,Default,,0000,0000,0000,,And so I figured out the\Nlast part of my equation.
Dialogue: 0,0:11:01.67,0:11:05.33,Default,,0000,0000,0000,,
Dialogue: 0,0:11:05.33,0:11:10.83,Default,,0000,0000,0000,,So going back to the\Ntop, we have sodium.
Dialogue: 0,0:11:10.83,0:11:13.81,Default,,0000,0000,0000,,And this turned\Nout to be a total
Dialogue: 0,0:11:13.81,0:11:22.71,Default,,0000,0000,0000,,of 140 milliosmoles per liter.
Dialogue: 0,0:11:22.71,0:11:30.33,Default,,0000,0000,0000,,And then for our anion, we had\N140 milliosmoles per liter.
Dialogue: 0,0:11:30.33,0:11:36.98,Default,,0000,0000,0000,,And then for our glucose, we\Nhad 5 milliosmoles per liter.
Dialogue: 0,0:11:36.98,0:11:42.79,Default,,0000,0000,0000,,And for our urea, we had\N5 milliosmoles per liter.
Dialogue: 0,0:11:42.79,0:11:49.46,Default,,0000,0000,0000,,So adding it all up, our total\Ncomes to 140 times 2 plus 10.
Dialogue: 0,0:11:49.46,0:11:52.03,Default,,0000,0000,0000,,So we get, if I do\Nmy math correctly,
Dialogue: 0,0:11:52.03,0:11:57.09,Default,,0000,0000,0000,,I think that's 290\Nmilliosmoles per liter.
Dialogue: 0,0:11:57.09,0:12:00.38,Default,,0000,0000,0000,,That's the answer\Nto our osmolarity.
Dialogue: 0,0:12:00.38,0:12:01.97,Default,,0000,0000,0000,,Our total osmolarity\Nin the plasma
Dialogue: 0,0:12:01.97,0:12:04.71,Default,,0000,0000,0000,,is 290 milliosmoles per liter.
Dialogue: 0,0:12:04.71,0:12:07.03,Default,,0000,0000,0000,,Now that was kind of the\Nlong way of doing it.
Dialogue: 0,0:12:07.03,0:12:09.46,Default,,0000,0000,0000,,Let me give you a very,\Nvery quick and dirty way
Dialogue: 0,0:12:09.46,0:12:09.96,Default,,0000,0000,0000,,of doing it.
Dialogue: 0,0:12:09.96,0:12:12.75,Default,,0000,0000,0000,,Let me actually make\Nsome space up here.
Dialogue: 0,0:12:12.75,0:12:15.38,Default,,0000,0000,0000,,You could do the exact same\Nproblem, you could say,
Dialogue: 0,0:12:15.38,0:12:24.90,Default,,0000,0000,0000,,well, this osmolarity\Nequals, you could say,
Dialogue: 0,0:12:24.90,0:12:40.80,Default,,0000,0000,0000,,sodium times 2, plus\Nglucose, divided by 18,
Dialogue: 0,0:12:40.80,0:12:45.45,Default,,0000,0000,0000,,plus BUN divided by 2.8.
Dialogue: 0,0:12:45.45,0:12:48.37,Default,,0000,0000,0000,,And that takes all\Nof those conversions
Dialogue: 0,0:12:48.37,0:12:49.65,Default,,0000,0000,0000,,and simplifies it down.
Dialogue: 0,0:12:49.65,0:12:52.85,Default,,0000,0000,0000,,So if you ever get your sodium\Nvalue, your glucose value,
Dialogue: 0,0:12:52.85,0:12:55.03,Default,,0000,0000,0000,,and your BUN, and you\Nwant to quickly calculate
Dialogue: 0,0:12:55.03,0:12:59.23,Default,,0000,0000,0000,,your osmolarity, now you\Nknow the fast way to do it.