WEBVTT 00:00:06.059 --> 00:00:09.800 Welcome to the bed. We'll go ahead and give you 00:00:09.800 --> 00:00:12.580 the story. This is all going to happen super 00:00:12.580 --> 00:00:43.729 fast. Welcome to the emergency room. Imagine, 00:00:47.450 --> 00:00:49.530 for a second, a heart the size of a strawberry. 00:00:50.229 --> 00:00:54.399 It's beating 150 times a minute. It's essentially 00:00:54.399 --> 00:00:57.979 sprinting a marathon. But the baby is lying completely 00:00:57.979 --> 00:01:00.560 still in a plastic warmer. Yeah. And then you 00:01:00.560 --> 00:01:02.719 introduce a structural flaw. The plumbing is 00:01:02.719 --> 00:01:06.519 just, it's wired wrong. Exactly. The pipes are 00:01:06.519 --> 00:01:09.459 crossed, or maybe a wall is missing, or a valve 00:01:09.459 --> 00:01:12.180 is basically welded shut. It's a mechanical nightmare. 00:01:12.260 --> 00:01:14.840 And for the parents, it is, I mean, it's absolutely 00:01:14.840 --> 00:01:17.500 terrifying. Right. And now, put yourself in the 00:01:17.500 --> 00:01:19.319 shoes of the nurse standing at that bedside. 00:01:19.420 --> 00:01:21.900 You have to infuse a medication into that tiny 00:01:21.900 --> 00:01:23.959 system. Yeah. If you get the math wrong or if 00:01:23.959 --> 00:01:26.620 you push it too fast or miss a subtle cue on 00:01:26.620 --> 00:01:28.739 the monitor. You can stop that heart. Or stop 00:01:28.739 --> 00:01:30.920 that baby from breathing. That is the reality 00:01:30.920 --> 00:01:34.299 of the pediatric cardiac ICU. It's high stakes, 00:01:34.620 --> 00:01:37.260 high stress, and incredibly precise. The margin 00:01:37.260 --> 00:01:39.700 for error is, well, it's effectively zero. Which 00:01:39.700 --> 00:01:42.200 is exactly why we're doing this deep dive. We 00:01:42.200 --> 00:01:44.379 aren't just reading drug labels today. We've 00:01:44.379 --> 00:01:47.420 taken this massive stack of textbooks, clinical 00:01:47.420 --> 00:01:50.200 guidelines, and drug monographs resources that 00:01:50.200 --> 00:01:52.879 would honestly take weeks to digest. And we're 00:01:52.879 --> 00:01:54.519 filtering them. We're looking for the Pareto 00:01:54.519 --> 00:01:57.060 principle. The 80 -20 rule. Exactly. We want 00:01:57.060 --> 00:01:59.599 the 20 % of the pharmacological knowledge that 00:01:59.599 --> 00:02:02.540 is going to drive 80 % of your clinical decisions 00:02:02.540 --> 00:02:05.900 and, you know, answer 80 % of those really difficult 00:02:05.900 --> 00:02:08.419 board exam questions. So if you're prepping for 00:02:08.419 --> 00:02:11.099 the NC... or if you're just trying to survive 00:02:11.099 --> 00:02:14.580 your first shift with a blue baby, this is what 00:02:14.580 --> 00:02:16.360 you need. This is your roadmap. And we should 00:02:16.360 --> 00:02:18.020 be really clear about the scope here. We're going 00:02:18.020 --> 00:02:21.560 to touch on defects, tetralogy of phallate, transposition 00:02:21.560 --> 00:02:23.900 of the great arteries, but only as context. We 00:02:23.900 --> 00:02:26.800 aren't teaching pathophysiology today. No, we're 00:02:26.800 --> 00:02:29.500 teaching the chemical tools you use to manage 00:02:29.500 --> 00:02:32.580 it, to fix it. We have four main stops on this 00:02:32.580 --> 00:02:35.289 roadmap. First, we've got ductal dynamics. These 00:02:35.289 --> 00:02:37.530 are the drugs that manipulate the fetal bypass. 00:02:37.669 --> 00:02:40.509 The on -off switch. Then the failure fixers, 00:02:40.590 --> 00:02:43.750 how we manage volume and squeeze. After that, 00:02:44.169 --> 00:02:47.870 rhythm and flow, controlling the speed and the 00:02:47.870 --> 00:02:50.150 thickness of the blood. And finally, the acquired 00:02:50.150 --> 00:02:53.349 trio, the diseases kids can catch that actually 00:02:53.349 --> 00:02:55.469 attack the heart. It's a heavy list, but we are 00:02:55.469 --> 00:02:57.090 going to break it down so it sticks. Let's just 00:02:57.090 --> 00:03:00.349 get right into it. Section one. Ductal dynamics. 00:03:00.689 --> 00:03:03.590 This is the battle between open and closed. Right. 00:03:04.449 --> 00:03:07.629 And looking at the literature, everything here, 00:03:07.689 --> 00:03:09.550 it just revolves around one single structure, 00:03:10.490 --> 00:03:13.050 the ductus arteriosus. OK. So set the scene for 00:03:13.050 --> 00:03:15.310 us. Biologically, what are we actually looking 00:03:15.310 --> 00:03:17.360 at? You have to remember that a fetus doesn't 00:03:17.360 --> 00:03:20.319 use its lungs. In the womb, the lungs are fluid 00:03:20.319 --> 00:03:22.340 filled and they're under high pressure. They 00:03:22.340 --> 00:03:24.340 are, for all intents and purposes, closed for 00:03:24.340 --> 00:03:26.020 business. But the heart is still pumping. The 00:03:26.020 --> 00:03:28.520 heart is still pumping blood. So nature created 00:03:28.520 --> 00:03:31.460 this incredible bypass road, a physical vessel 00:03:31.460 --> 00:03:34.360 called the ductus arteriosus. And it connects 00:03:34.360 --> 00:03:36.960 the pulmonary artery directly to the aorta. So 00:03:36.960 --> 00:03:38.979 blood leaves the right side of the heart. It 00:03:38.979 --> 00:03:41.699 heads toward the lungs, hits a road closed sign, 00:03:41.860 --> 00:03:44.099 and just takes the ductus off ramp straight to 00:03:44.099 --> 00:03:47.550 the body. Precisely. It skips the lungs entirely 00:03:47.550 --> 00:03:49.710 because the placenta is doing all the breathing 00:03:49.710 --> 00:03:51.729 for the baby. Okay, so what happens at birth? 00:03:52.129 --> 00:03:54.669 Well, normally when a baby is born and takes 00:03:54.669 --> 00:03:57.569 that first breath two things happen The lungs 00:03:57.569 --> 00:04:00.430 expand which drops the pressure and the oxygen 00:04:00.430 --> 00:04:03.370 levels in the blood just shoot up That surge 00:04:03.370 --> 00:04:06.069 of oxygen trigger the chemical reaction that 00:04:06.069 --> 00:04:08.580 clamps that vessel shot. That's just Usually 00:04:08.580 --> 00:04:10.780 within a few days, it's totally closed. It becomes 00:04:10.780 --> 00:04:13.280 a ligament. It's not a factor anymore. But here's 00:04:13.280 --> 00:04:15.379 the crux of the problem for congenital heart 00:04:15.379 --> 00:04:18.160 defects. In some of these babies, that closure 00:04:18.160 --> 00:04:20.720 is catastrophic. Great. If you have a defect 00:04:20.720 --> 00:04:23.040 like pulmonary atresia, where the normal road 00:04:23.040 --> 00:04:25.500 to the lungs is completely blocked, or maybe 00:04:25.500 --> 00:04:27.420 hypoplastic left heart syndrome, where the road 00:04:27.420 --> 00:04:30.420 to the body is blocked, the ductus is the only 00:04:30.420 --> 00:04:33.100 thing keeping the baby alive. It's the only bridge. 00:04:33.220 --> 00:04:35.480 It is the only bridge allowing blood to get where 00:04:35.480 --> 00:04:38.310 it needs to go. If nature takes its course and 00:04:38.310 --> 00:04:41.649 closes that duct, the baby dies. It's that simple. 00:04:41.790 --> 00:04:44.430 So we need a chemical doorstop. We need something 00:04:44.430 --> 00:04:47.269 to physically jam that pathway open until the 00:04:47.269 --> 00:04:49.509 surgeons can get in there and operate. And that 00:04:49.509 --> 00:04:53.009 brings us to drug number one, alprostadil. Also 00:04:53.009 --> 00:04:56.470 known as prostaglandin E1 or PGE1. Yeah. If you 00:04:56.470 --> 00:04:59.810 work in an NACU or a CVICU, this is arguably 00:04:59.810 --> 00:05:02.170 the single most critical drug in your crash cart. 00:05:02.610 --> 00:05:04.550 It is a lifesaver. Let's start with the basics. 00:05:04.769 --> 00:05:06.879 Drug description. I'm looking at the monograph 00:05:06.879 --> 00:05:09.759 here, and it just says it's a potent, smooth 00:05:09.759 --> 00:05:12.600 muscle relaxant. And that's the key phrase. The 00:05:12.600 --> 00:05:15.720 ductus is a muscular vessel. Alprostidyl tells 00:05:15.720 --> 00:05:20.000 that muscle to relax. Just chill out. By relaxing, 00:05:20.399 --> 00:05:22.839 it prevents it from constricting. It maintains 00:05:22.839 --> 00:05:25.439 ductal patency. That's the term you'll hear in 00:05:25.439 --> 00:05:27.720 report. We're running prostin to maintain patency. 00:05:28.040 --> 00:05:29.920 OK, so let's dig into the mechanism of action. 00:05:30.100 --> 00:05:33.269 It's relaxing the smooth muscle. How? It binds 00:05:33.269 --> 00:05:35.689 to prostaglandin receptors on the muscle cells 00:05:35.689 --> 00:05:38.350 of the ductus. This activates a cascade inside 00:05:38.350 --> 00:05:40.769 the cell that basically prevents calcium from 00:05:40.769 --> 00:05:43.189 entering. Without that influx of calcium, the 00:05:43.189 --> 00:05:45.029 muscle just can't contract. It's forced to stay 00:05:45.029 --> 00:05:47.769 dilated. So practically speaking, if I'm in report 00:05:47.769 --> 00:05:50.470 and I hear the phrase ductal -dependent lesion, 00:05:50.610 --> 00:05:52.970 my brain should immediately jump to elprostidil. 00:05:53.269 --> 00:05:56.329 Instantly. It's a direct one -to -one link. If 00:05:56.329 --> 00:05:58.410 the baby's life depends on the ductus being open, 00:05:58.829 --> 00:06:00.569 this is the drug they will be on. Let's talk 00:06:00.569 --> 00:06:03.410 about specific defects. The outline links this 00:06:03.410 --> 00:06:06.730 to transposition of the great arteries, or TGA. 00:06:07.029 --> 00:06:09.970 Right. In TGA, the plumbing is completely swapped. 00:06:10.410 --> 00:06:12.209 The blue blood from the body goes to the right 00:06:12.209 --> 00:06:14.490 heart and back to the body. The red blood from 00:06:14.490 --> 00:06:16.730 the lungs goes to the left heart and back to 00:06:16.730 --> 00:06:18.930 the lungs. They never mix. They never mix. It's 00:06:18.930 --> 00:06:21.879 two separate circles. That baby will die from 00:06:21.879 --> 00:06:23.959 hypoxia within minutes unless you have somewhere 00:06:23.959 --> 00:06:26.540 for the blood to mix. The open ductus allows 00:06:26.540 --> 00:06:29.459 that. It lets some of that red oxygenated blood 00:06:29.459 --> 00:06:31.660 cross over into the aorta and get to the body. 00:06:31.899 --> 00:06:34.639 So it's a bridge. What about something like tricuspid 00:06:34.639 --> 00:06:37.860 atresia or pulmonary atresia? In those cases, 00:06:38.259 --> 00:06:40.339 the valve leading to the lungs is either missing 00:06:40.339 --> 00:06:43.439 or sealed shut. No blood can get from the right 00:06:43.439 --> 00:06:45.300 side of the heart to the lungs the normal way. 00:06:45.779 --> 00:06:48.160 The ductus is the only source of pulmonary blood 00:06:48.160 --> 00:06:50.810 flow. So blood goes from the aorta, backward, 00:06:51.009 --> 00:06:53.490 through the ductus, and into the pulmonary artery. 00:06:53.689 --> 00:06:56.149 Exactly. It's a reverse flow, but it's the only 00:06:56.149 --> 00:06:58.490 way to get blood oxygenated. Okay. And on the 00:06:58.490 --> 00:07:01.050 other side of things, hypoplastic left heart 00:07:01.050 --> 00:07:05.470 syndrome, HLHS. In HLHS, the entire left side 00:07:05.470 --> 00:07:07.689 of the heart is underdeveloped. It can't pump 00:07:07.689 --> 00:07:09.949 blood to the body. So again, the ductus is the 00:07:09.949 --> 00:07:12.470 only source of systemic blood flow. The right 00:07:12.470 --> 00:07:14.629 ventricle pumps blood to the pulmonary artery, 00:07:14.649 --> 00:07:16.769 and then it crosses the ductus to get to the 00:07:16.769 --> 00:07:19.439 aorta and feed the body. So in all these cases, 00:07:19.759 --> 00:07:22.660 if that duct closes, it's game over. Game over. 00:07:23.079 --> 00:07:25.379 Now, when we start this infusion, what are we 00:07:25.379 --> 00:07:27.399 actually watching for? How do we know it's working? 00:07:27.540 --> 00:07:30.779 This is the core need to know stuff. The therapeutic 00:07:30.779 --> 00:07:33.180 effect depends entirely on the defect. It's all 00:07:33.180 --> 00:07:35.480 about what you're trying to achieve. So if the 00:07:35.480 --> 00:07:38.079 baby is blue cyanotic, because blood can't get 00:07:38.079 --> 00:07:40.360 to the lungs, like in pulmonary atresia. You 00:07:40.360 --> 00:07:42.899 watch the O2 sats. Yeah. You start the drug. 00:07:43.290 --> 00:07:45.689 and you should see the baby literally turn pink 00:07:45.689 --> 00:07:47.730 in front of your eyes. The saturations climb 00:07:47.730 --> 00:07:50.730 from, say, the 50s or 60s up into the 80s. And 00:07:50.730 --> 00:07:53.529 if it's an obstructive lesion, like a severe 00:07:53.529 --> 00:07:56.430 coarctation of the aorta where the aorta is pinched? 00:07:56.550 --> 00:07:59.250 Then you're watching for perfusion. Before the 00:07:59.250 --> 00:08:02.319 drug... The baby might have cold legs, pale skin, 00:08:02.459 --> 00:08:05.100 and you can't feel the femoral pulses. The blood 00:08:05.100 --> 00:08:07.420 pressure in the legs will be way lower than the 00:08:07.420 --> 00:08:09.920 arms. Right. You start the L -prostil, the duct 00:08:09.920 --> 00:08:12.959 opens, and it provides blood flow to the body 00:08:12.959 --> 00:08:15.579 after the pinch point. Suddenly, you can feel 00:08:15.579 --> 00:08:18.360 pulses again. The lactate levels, which were 00:08:18.360 --> 00:08:21.240 high from poor perfusion, start to drop. The 00:08:21.240 --> 00:08:24.519 baby looks, for lack of a better word, alive 00:08:24.519 --> 00:08:26.800 again. That sounds like a miracle drug, but looking 00:08:26.800 --> 00:08:29.339 at the side effect profile here, this is rough. 00:08:29.459 --> 00:08:32.919 There is a boxed warning that seems to be a favorite 00:08:32.919 --> 00:08:35.960 for exam writers. Apnea. It stops them from breathing. 00:08:36.059 --> 00:08:38.480 It's a very, very real risk. Alprostidyl has 00:08:38.480 --> 00:08:40.419 a central effect on the respiratory drive and 00:08:40.419 --> 00:08:43.379 the brain stem. The data says about 10 % to 12 00:08:43.379 --> 00:08:45.639 % of neonates will have an apneic spell. One 00:08:45.639 --> 00:08:47.799 in 10. Yeah, and it usually happens quickly, 00:08:48.100 --> 00:08:49.860 typically within the first hour of starting the 00:08:49.860 --> 00:08:51.960 infusion. This feels like a massive trap for 00:08:51.960 --> 00:08:54.220 a new nurse. I can see the exam question now. 00:08:54.519 --> 00:08:57.519 You start alprostidyl on a newborn with TGA. 00:08:57.860 --> 00:09:00.000 Fifteen minutes later, the baby stops breathing. 00:09:00.480 --> 00:09:03.379 What is your priority action? And the distractors 00:09:03.379 --> 00:09:06.419 will be things like stop the infusion or administer 00:09:06.419 --> 00:09:10.200 epinephrine or call the provider. All sound plausible. 00:09:10.320 --> 00:09:13.179 But you do not stop the infusion. Never. That's 00:09:13.179 --> 00:09:15.179 the trap. If you stop the infusion, the duct 00:09:15.179 --> 00:09:18.000 closes and the underlying heart defect kills 00:09:18.000 --> 00:09:21.519 the baby. Apnea is a known, expected side effect, 00:09:21.879 --> 00:09:24.179 not an allergy. So you treat the side effect. 00:09:24.250 --> 00:09:26.309 You treat the side effect, you get your bag valve 00:09:26.309 --> 00:09:28.809 mask, you support their breathing, and you call 00:09:28.809 --> 00:09:31.149 for help to get them intubated. You ventilate 00:09:31.149 --> 00:09:33.610 them. But you keep that prostaglandin running 00:09:33.610 --> 00:09:37.110 at all costs. So the number one nursing implication, 00:09:37.429 --> 00:09:40.370 the absolute safety priority, is never start 00:09:40.370 --> 00:09:42.769 this drug without an airway cart at the bedside. 00:09:42.950 --> 00:09:45.629 Correct. Intubation equipment, suction, a ventilator, 00:09:45.809 --> 00:09:48.490 immediately available. In fact, if we're transporting 00:09:48.490 --> 00:09:51.169 a baby on alprostitl, say, in a helicopter or 00:09:51.169 --> 00:09:54.470 ambulance, We almost always intubate them electively 00:09:54.470 --> 00:09:57.289 beforehand. Proactively. Exactly. You do not 00:09:57.289 --> 00:09:59.970 want to be trying to intubate a tiny unstable 00:09:59.970 --> 00:10:02.090 neonate in the back of a moving ambulance because 00:10:02.090 --> 00:10:03.690 the drug kicked in and they stopped breathing. 00:10:04.070 --> 00:10:06.370 It's all about anticipation. That makes perfect 00:10:06.370 --> 00:10:10.230 sense. I also see fever and flushing listed here 00:10:10.230 --> 00:10:12.549 as a common side effect. Is that an infection 00:10:12.549 --> 00:10:15.769 risk? Usually not. It's a systemic vasodilator. 00:10:16.049 --> 00:10:18.250 It opens blood vessels everywhere, not just the 00:10:18.250 --> 00:10:20.570 ductus. So the baby turns red, gets hot to the 00:10:20.570 --> 00:10:22.929 touch. It can look really alarming like a sepsis 00:10:22.929 --> 00:10:24.990 flare, but it's usually just the drug working. 00:10:25.190 --> 00:10:27.250 So you treat the temperature, maybe unswaddle 00:10:27.250 --> 00:10:29.409 them, but you don't panic and start a sepsis 00:10:29.409 --> 00:10:32.110 workup immediately. You don't panic. You also 00:10:32.110 --> 00:10:35.169 need to watch for cardiovascular collapse. So 00:10:35.169 --> 00:10:38.230 hypotension and brachycardia. if the baby is 00:10:38.230 --> 00:10:40.129 particularly sensitive or if the drug is pushed 00:10:40.129 --> 00:10:43.409 too fast. But apnea is the big one, the one you 00:10:43.409 --> 00:10:45.629 have to be ready for. What about administration? 00:10:45.809 --> 00:10:47.870 Can I run this through a peripheral IV in the 00:10:47.870 --> 00:10:50.529 hand? You can, but it's risky. It's tough on 00:10:50.529 --> 00:10:53.470 the veins and you can lose access. Ideally, you 00:10:53.470 --> 00:10:57.149 want a secure central line or a UAC and umbilical 00:10:57.149 --> 00:11:00.149 artery catheter. And here's a rigid rule. This 00:11:00.149 --> 00:11:02.690 is a continuous infusion only. Meaning no interruptions. 00:11:02.870 --> 00:11:04.730 Zero interruptions. You never flush the line, 00:11:04.929 --> 00:11:06.789 you never bolus it, and you absolutely never 00:11:06.789 --> 00:11:08.889 let the bag run dry. Because the half -life is 00:11:08.889 --> 00:11:11.750 incredibly short. Seconds to minutes. If that 00:11:11.750 --> 00:11:14.470 pump beeps infusion complete and you ignore it 00:11:14.470 --> 00:11:16.509 for five minutes while you go get another bag, 00:11:16.929 --> 00:11:19.379 the duct can start to spasm shut. Wow. And once 00:11:19.379 --> 00:11:22.240 it clamps down, it is very, very hard to pry 00:11:22.240 --> 00:11:24.440 it open again. The standard of care is to have 00:11:24.440 --> 00:11:26.620 the next bag mixed and ready and you run two 00:11:26.620 --> 00:11:28.419 pumps to switch it over so there is literally 00:11:28.419 --> 00:11:31.100 zero interruption in the flow. That's a huge 00:11:31.100 --> 00:11:34.039 nursing responsibility. It is. It's a life -sustaining 00:11:34.039 --> 00:11:37.179 infusion. Okay, any nice -to -know facts about 00:11:37.179 --> 00:11:39.600 alprostidyl before we move on? Well, the name 00:11:39.600 --> 00:11:42.100 itself comes from its discovery in seminal fluid 00:11:42.100 --> 00:11:45.220 from the prostate gland. It's also used for erectile 00:11:45.220 --> 00:11:48.179 dysfunction in adults in products like cavergect 00:11:48.179 --> 00:11:51.039 or MEWS. Same molecule, totally different application. 00:11:51.539 --> 00:11:53.860 Fascinating. And one other thing for kids who 00:11:53.860 --> 00:11:56.600 are on it long -term, like for weeks while awaiting 00:11:56.600 --> 00:11:59.179 transplant, it can cause something called cortical 00:11:59.179 --> 00:12:01.159 proliferation, which is a weird thickening of 00:12:01.159 --> 00:12:03.440 the long bones. It's reversible, but something 00:12:03.440 --> 00:12:06.399 to know. OK, so I'll process until jams the door 00:12:06.399 --> 00:12:09.039 open, but let's flip the script. Sometimes we 00:12:09.039 --> 00:12:11.600 have the opposite problem. The heart is structurally 00:12:11.600 --> 00:12:14.539 normal, but the baby is premature and the ductus 00:12:14.539 --> 00:12:17.179 won't close. Right. This is the classic patent 00:12:17.179 --> 00:12:21.220 ductus arteriosus or PDA. In a preemie, the lungs 00:12:21.220 --> 00:12:23.779 are incredibly fragile. If that duct stays open, 00:12:24.360 --> 00:12:26.679 high -pressure blood from the aorta floods into 00:12:26.679 --> 00:12:29.019 the low -pressure pulmonary artery. It's called 00:12:29.019 --> 00:12:32.100 pulmonary overcirculation. Exactly. The lungs 00:12:32.100 --> 00:12:35.279 get wet, heavy, boggy, the baby needs more ventilator 00:12:35.279 --> 00:12:37.700 support, and the heart eventually fails trying 00:12:37.700 --> 00:12:39.799 to pump against all that extra flow. So we need 00:12:39.799 --> 00:12:41.759 to do the opposite of alprostidol. We need to 00:12:41.759 --> 00:12:44.360 close it. Enter drug number two, indomethacin. 00:12:44.759 --> 00:12:47.740 Indomethacin, an NSAI. It's in the same family 00:12:47.740 --> 00:12:49.759 as ibuprofen or motrin. But we aren't giving 00:12:49.759 --> 00:12:52.210 it for a headache or a fever. No. We are using 00:12:52.210 --> 00:12:54.690 its primary mechanism of action as our therapeutic 00:12:54.690 --> 00:12:58.549 effect. Indomethacin is an inhibitor of cyclooxygenase 00:12:58.549 --> 00:13:03.009 enzymes, QOX1 and QOX2. And QS enzymes are the 00:13:03.009 --> 00:13:05.090 factories that build prostaglandins. I see you're 00:13:05.090 --> 00:13:08.129 making the connection. Yes. Alprostidyl is a 00:13:08.129 --> 00:13:11.129 prostaglandin. It keeps the duct open. Indomethacin 00:13:11.129 --> 00:13:13.149 stops the body from making prostaglandins in 00:13:13.149 --> 00:13:16.090 the first place. Exactly. You fire the construction 00:13:16.090 --> 00:13:19.509 crew. No COX enzymes, no prostaglandins. And 00:13:19.509 --> 00:13:22.509 since the ductus needs a constant supply of prostaglandins 00:13:22.509 --> 00:13:25.149 to stay open without them, it loses its signal 00:13:25.149 --> 00:13:27.889 and it constricts. It's a chemical clamp. It 00:13:27.889 --> 00:13:30.450 sounds brilliant, but looking at the safety data... 00:13:30.939 --> 00:13:33.500 Endomethacin feels like a dirty drug. It hits 00:13:33.500 --> 00:13:35.539 a lot of different systems. It does. It's not 00:13:35.539 --> 00:13:37.320 a precision weapon. It's more like a shotgun. 00:13:37.460 --> 00:13:39.620 Yeah. And the two battlegrounds you have to watch 00:13:39.620 --> 00:13:42.039 very, very closely are the kidneys and the gut. 00:13:42.240 --> 00:13:45.080 Why the kidneys? What's the link? Because prostaglandins 00:13:45.080 --> 00:13:47.360 play a huge role in maintaining blood flow to 00:13:47.360 --> 00:13:50.100 the kidneys, especially in a fragile, stressed 00:13:50.100 --> 00:13:53.059 newborn. They keep the renal arteries dilated. 00:13:53.519 --> 00:13:56.100 When you give endomethacin and wipe out the prostaglandins 00:13:56.100 --> 00:13:58.830 to close the heart duct, You inadvertently clamp 00:13:58.830 --> 00:14:01.129 down on the renal arteries, too. You do. You 00:14:01.129 --> 00:14:03.490 can cause a significant reduction in renal blood 00:14:03.490 --> 00:14:06.250 flow, leading to an acute kidney injury. So what's 00:14:06.250 --> 00:14:08.830 the nursing implication? What do I monitor? Urine 00:14:08.830 --> 00:14:11.669 output. Meticulously. You're calculating it every 00:14:11.669 --> 00:14:15.169 hour. If the urine output drops, if you see oliguria, 00:14:15.389 --> 00:14:17.789 or if the baby becomes an uric with no urine 00:14:17.789 --> 00:14:20.429 at all, you have to hold the drug. You also monitor 00:14:20.429 --> 00:14:22.929 the serum creatinine. If it's elevated, that's 00:14:22.929 --> 00:14:25.250 a red flag. So the exam question might describe 00:14:25.250 --> 00:14:28.029 a preemie with a PDA scheduled for endomethacin, 00:14:28.090 --> 00:14:31.149 but their creatinine is high and their UOP is 00:14:31.149 --> 00:14:34.090 low. And the answer is, hold the drug and notify 00:14:34.090 --> 00:14:36.429 the provider. You cannot sacrifice the kidneys 00:14:36.429 --> 00:14:38.470 just to close the duct. You might have to go 00:14:38.470 --> 00:14:40.789 to surgical ligation instead. OK, that's the 00:14:40.789 --> 00:14:43.669 kidneys. Now the gut. Same mechanism. Reduced 00:14:43.669 --> 00:14:46.409 blood flow, this time to the intestines. In a 00:14:46.409 --> 00:14:48.909 premature baby, this is the absolute nightmare 00:14:48.909 --> 00:14:53.120 scenario. NEC. Necrotizing enterocolitis. Where 00:14:53.120 --> 00:14:55.700 the bowel tissue literally dies. It dies because 00:14:55.700 --> 00:14:57.860 it isn't getting enough blood. Bacteria invade 00:14:57.860 --> 00:15:00.519 the bowel wall and the gut can perforate, spilling 00:15:00.519 --> 00:15:03.059 stool into the abdomen. It's a surgical emergency 00:15:03.059 --> 00:15:05.220 with a high mortality rate. So as a nurse, what 00:15:05.220 --> 00:15:08.580 am I looking for? A distended, firm, shiny belly. 00:15:09.500 --> 00:15:11.740 Bloody stools, you might need to do a guayac 00:15:11.740 --> 00:15:15.059 test on the stool. Vomiting, especially green, 00:15:15.559 --> 00:15:18.259 bilious vomit. Any of those signs are a hard 00:15:18.259 --> 00:15:20.980 stop. So the big contraindications are active 00:15:20.980 --> 00:15:23.480 bleeding, like an intraventricular hemorrhage, 00:15:23.779 --> 00:15:26.340 existing kidney problems, or any signs of NEC? 00:15:26.580 --> 00:15:28.360 Correct. You have to assess for those things 00:15:28.360 --> 00:15:31.299 before every single dose. What about the therapeutic 00:15:31.299 --> 00:15:33.379 effect? How do you know it worked? You listen 00:15:33.379 --> 00:15:37.519 to the heart. A PDA has a very characteristic 00:15:37.519 --> 00:15:41.529 machinery -like murmur. After a course of endomethacin, 00:15:41.789 --> 00:15:44.070 that murmur should be gone. You'll also see the 00:15:44.070 --> 00:15:46.669 baby's respiratory status improve. They'll need 00:15:46.669 --> 00:15:48.470 less ventilator support because their lungs aren't 00:15:48.470 --> 00:15:50.389 flooded anymore. Is there anything in the nice 00:15:50.389 --> 00:15:53.090 -to -know category for endomethacin? Yeah, another 00:15:53.090 --> 00:15:56.350 5e NSAI called ibuprofen lysine is sometimes 00:15:56.350 --> 00:15:58.769 used as an alternative. Some studies suggest 00:15:58.769 --> 00:16:01.009 it might have slightly fewer renal side effects, 00:16:01.029 --> 00:16:03.509 but endomethacin is still the classic prototype 00:16:03.509 --> 00:16:05.730 you'll see on exams. And it can mask a fever, 00:16:05.909 --> 00:16:08.409 right, since it's an anti -inflammatory? It can. 00:16:08.970 --> 00:16:11.269 You can't rely on temperature as your only sign 00:16:11.269 --> 00:16:13.610 of infection in a baby getting this drug. You 00:16:13.610 --> 00:16:15.529 have to look at the whole clinical picture. Okay, 00:16:15.970 --> 00:16:19.070 so ductal dynamics in a nutshell. All prostidyl 00:16:19.070 --> 00:16:21.169 opens the door but might stop the breathing. 00:16:21.950 --> 00:16:24.210 Endomethacin slams the door but might starve 00:16:24.210 --> 00:16:26.809 the kidneys and gut. That's the 80 -20 right 00:16:26.809 --> 00:16:29.629 there. Understand that prostaglandin switch and 00:16:29.629 --> 00:16:32.049 you understand both drugs. Perfect. Let's move 00:16:32.049 --> 00:16:35.509 to section two. The failure fixers. We've managed 00:16:35.509 --> 00:16:37.789 the plumbing, the ductus, but now we have to 00:16:37.789 --> 00:16:40.590 deal with the pump itself. A lot of these kids, 00:16:40.649 --> 00:16:42.110 whether they have a hole in the heart, like a 00:16:42.110 --> 00:16:45.250 large VSD or an AV canal defect, they have a 00:16:45.250 --> 00:16:48.690 heart that is just boggy. It's volume overloaded. 00:16:48.789 --> 00:16:51.110 They're in heart failure. And it looks just like 00:16:51.110 --> 00:16:53.909 adult heart failure, but in a tiny body. You 00:16:53.909 --> 00:16:56.649 see periorbital edema puffy eyes to chipnia. 00:16:57.070 --> 00:17:00.129 So rapid breeding and a classic sign in babies 00:17:00.129 --> 00:17:02.629 is sweating while feeding. Diaphoresis. with 00:17:02.629 --> 00:17:04.869 feeding. That's the term. It's like they're running 00:17:04.869 --> 00:17:06.930 a marathon just to drink a bottle. It's a huge 00:17:06.930 --> 00:17:09.269 red flag. And they fail to thrive because all 00:17:09.269 --> 00:17:11.170 their calories are being burned just to breathe 00:17:11.170 --> 00:17:13.710 and pump. The heart is just drowning in fluid. 00:17:14.029 --> 00:17:17.190 So our first job is to unload the wagon. And 00:17:17.190 --> 00:17:20.390 that brings us to drug number three, the gold 00:17:20.390 --> 00:17:24.349 standard for this, furosemide. Lasix, the absolute 00:17:24.349 --> 00:17:27.170 workhorse of pediatric cardiology. The class 00:17:27.170 --> 00:17:30.170 is a loop diuretic. Let's break down the mechanism 00:17:30.170 --> 00:17:32.670 of action in simple terms. How does it actually 00:17:32.670 --> 00:17:35.750 get fluid out of the body? It works in a specific 00:17:35.750 --> 00:17:37.589 part of the kidney called the ascending loop 00:17:37.589 --> 00:17:41.109 of Henlo. In that spot, it blocks a transporter 00:17:41.109 --> 00:17:43.769 protein that's responsible for reabsorbing sodium, 00:17:44.150 --> 00:17:46.190 chloride, and potassium back into the blood. 00:17:46.569 --> 00:17:48.809 And water follows salt? Water always follows 00:17:48.809 --> 00:17:50.930 salt. If the kidney can't reabsorb the salt, 00:17:51.029 --> 00:17:52.789 the salt stays in the urine, the water stays 00:17:52.789 --> 00:17:55.329 with it, and the baby just pees out a huge volume 00:17:55.329 --> 00:17:57.710 of fluid. Simple enough. You give the drug, the 00:17:57.710 --> 00:17:59.789 diaper gets heavy, the lungs get clearer, the 00:17:59.789 --> 00:18:02.210 breathing gets easier. That's the therapeutic 00:18:02.210 --> 00:18:04.890 effect we want. Right. Decreased edema, clearer 00:18:04.890 --> 00:18:07.529 lung sounds on auscultation, and an improved 00:18:07.529 --> 00:18:10.109 work of breathing. But diuretics, especially 00:18:10.109 --> 00:18:13.349 loop diuretics, are famous for messing with electrolytes. 00:18:13.710 --> 00:18:16.190 What is the specific imbalance we are terrified 00:18:16.190 --> 00:18:21.130 of with Lasix? Potassium. Lasix is a potent potassium 00:18:21.130 --> 00:18:23.869 -wasting diuretic. It kicks potassium out right 00:18:23.869 --> 00:18:26.630 along with the water. You are at a very high 00:18:26.630 --> 00:18:29.630 risk for hypoklemia, low potassium. And why does 00:18:29.630 --> 00:18:32.029 low potassium matter so much for these cardiac 00:18:32.029 --> 00:18:35.490 kids? Two big reasons. First, low potassium makes 00:18:35.490 --> 00:18:38.029 the heart muscle irritable. It can cause arrhythmias, 00:18:38.210 --> 00:18:41.109 PVCs, even more dangerous rhythms. But the second 00:18:41.109 --> 00:18:44.069 reason is a classic drug interaction that is 00:18:44.069 --> 00:18:47.710 pure exam gold. Digoxin. Digoxin. Many of these 00:18:47.710 --> 00:18:50.309 heart failure kids are also on digoxin to help 00:18:50.309 --> 00:18:52.490 the heart squeeze more effectively. And I remember 00:18:52.490 --> 00:18:54.970 this from nursing school, potassium and digoxin 00:18:54.970 --> 00:18:57.210 compete. They compete for the same binding sites 00:18:57.210 --> 00:18:59.470 on the heart muscle. Think of it like a game 00:18:59.470 --> 00:19:02.089 of musical chairs. If potassium levels are normal, 00:19:02.109 --> 00:19:04.329 there's healthy competition. But if potassium 00:19:04.329 --> 00:19:06.490 is low, there are all these empty chairs and 00:19:06.490 --> 00:19:09.049 digoxin can just bind everywhere way too aggressively. 00:19:09.250 --> 00:19:11.930 And you get digoxin toxicity. You get dig toxicity. 00:19:12.289 --> 00:19:14.130 And the earliest signs in an infant are often 00:19:14.130 --> 00:19:16.990 GI related. Vomiting is number one, not just 00:19:16.990 --> 00:19:19.269 spitting up, but real vomiting. So the nursing 00:19:19.269 --> 00:19:22.369 algorithm, the exam question is, a child on Lasix 00:19:22.369 --> 00:19:25.089 and Digoxin starts vomiting. Your first action 00:19:25.089 --> 00:19:28.130 is? Check a potassium level immediately. Do not 00:19:28.130 --> 00:19:30.549 just assume it's the flu or reflux. Vomiting 00:19:30.549 --> 00:19:33.630 is often the first and only sign of dig toxicity 00:19:33.630 --> 00:19:36.099 in an infant. So as the nurse, you're monitoring 00:19:36.099 --> 00:19:38.759 serum potassium levels like a hawk, and you're 00:19:38.759 --> 00:19:40.759 probably administering potassium supplements 00:19:40.759 --> 00:19:44.140 like Kdur or IV potassium chloride. Constantly. 00:19:44.299 --> 00:19:46.259 It's a daily battle to keep their potassium in 00:19:46.259 --> 00:19:48.539 the normal range. There's another major safety 00:19:48.539 --> 00:19:50.480 warning here for Lasix that I think a lot of 00:19:50.480 --> 00:19:54.640 people miss. The monograph highlights ototoxicity. 00:19:54.920 --> 00:19:58.670 Yes. Hearing loss. This is almost always associated 00:19:58.670 --> 00:20:01.289 with IV administration and specifically with 00:20:01.289 --> 00:20:03.650 pushing it too fast. How does that happen? If 00:20:03.650 --> 00:20:07.349 you slam IV Lasix, it rapidly alters the electrolyte 00:20:07.349 --> 00:20:09.750 balance in the fluid of the inner ear, the endolith. 00:20:10.450 --> 00:20:12.769 That sudden shift can damage the delicate hair 00:20:12.769 --> 00:20:14.849 cells that are responsible for hearing. And is 00:20:14.849 --> 00:20:17.710 that damage permanent? It can be. Often it's 00:20:17.710 --> 00:20:19.430 transient. But do you really want to be the nurse 00:20:19.430 --> 00:20:21.049 who made a child deaf because you didn't want 00:20:21.049 --> 00:20:22.569 to stand at the bedside for two extra minutes? 00:20:23.349 --> 00:20:26.150 Absolutely not. So what is the speed limit? The 00:20:26.150 --> 00:20:29.569 rule of thumb for pediatrics is you do not exceed 00:20:29.569 --> 00:20:33.130 0 .5 milligrams per kilogram per minute. For 00:20:33.130 --> 00:20:36.670 a bigger kid with a high dose, you are not slamming 00:20:36.670 --> 00:20:39.509 it in like a saline flush. You are pushing it 00:20:39.509 --> 00:20:41.809 slowly over several minutes. Or putting it on 00:20:41.809 --> 00:20:43.970 a pump. If the dose is large enough, we often 00:20:43.970 --> 00:20:45.910 just put it on a syringe pump to run over 10 00:20:45.910 --> 00:20:49.230 or 15 minutes just to be absolutely safe. Slow 00:20:49.230 --> 00:20:51.880 and steady saves the hearing. Okay, we've diareased 00:20:51.880 --> 00:20:54.059 them. We've lowered the preload, the amount of 00:20:54.059 --> 00:20:56.319 volume filling the heart. Now we need to help 00:20:56.319 --> 00:20:58.859 that tired heart push blood out. We need to lower 00:20:58.859 --> 00:21:01.019 the resistance it's pushing against. We need 00:21:01.019 --> 00:21:03.339 to reduce the afterload. Which brings us to drug 00:21:03.339 --> 00:21:07.759 number four, Lysinople. An AC inhibitor. That 00:21:07.759 --> 00:21:10.380 stands for angiotensin converting enzyme inhibitor. 00:21:10.519 --> 00:21:13.240 Right. So this drug's mechanism is blocking the 00:21:13.240 --> 00:21:16.000 conversion of angiotensin I to angiotensin II. 00:21:16.319 --> 00:21:18.519 And angiotensin II is one of the most potent 00:21:18.519 --> 00:21:21.440 vasoconstrictors the body makes. It clamps vessels 00:21:21.440 --> 00:21:23.460 down tight, which jacks up the blood pressure. 00:21:23.980 --> 00:21:26.619 By blocking its production, Lisinopril lets the 00:21:26.619 --> 00:21:28.880 arteries and veins relax and dilate. So it lowers 00:21:28.880 --> 00:21:31.160 the blood pressure. It lowers the blood pressure, 00:21:31.380 --> 00:21:34.240 which makes it much easier for a Wink failing 00:21:34.240 --> 00:21:37.029 hard to empty its chamber. It's like trying to 00:21:37.029 --> 00:21:39.630 push open a heavy spring -loaded door versus 00:21:39.630 --> 00:21:42.049 a door that's already wide open. It reduces the 00:21:42.049 --> 00:21:44.910 heart's workload. Now, let's contrast this with 00:21:44.910 --> 00:21:48.150 Lasix. We just said Lasix dumps potassium. What 00:21:48.150 --> 00:21:50.670 does lisinopril do to potassium? It does the 00:21:50.670 --> 00:21:54.250 exact opposite. ACE inhibitors are potassium 00:21:54.250 --> 00:21:57.869 sparing. By blocking part of the hormonal cascade, 00:21:58.430 --> 00:22:01.190 they decrease aldosterone levels, and aldosterone 00:22:01.190 --> 00:22:03.470 is what tells the kidneys to excrete potassium. 00:22:03.769 --> 00:22:06.309 so they make the kidneys hold on to potassium. 00:22:06.509 --> 00:22:09.029 So we have a perfect balancing act. The Lasix 00:22:09.029 --> 00:22:11.470 is pushing potassium out. The Lisinopril is holding 00:22:11.470 --> 00:22:13.529 it in. In an ideal world, they cancel each other 00:22:13.529 --> 00:22:15.789 out beautifully. But you have to monitor the 00:22:15.789 --> 00:22:18.230 lapse. You can't just blindly give potassium 00:22:18.230 --> 00:22:20.970 supplements if, say, the Lasix is held for a 00:22:20.970 --> 00:22:23.730 day, but the Lisinopril is still given. You could 00:22:23.730 --> 00:22:25.990 easily swing them into hyperkalemia. And high 00:22:25.990 --> 00:22:28.369 potassium is just as dangerous as low potassium. 00:22:28.390 --> 00:22:30.410 It can cause fatal arrhythmias. It stops the 00:22:30.410 --> 00:22:33.450 heart. OK. There are two other classic exam favorite 00:22:33.450 --> 00:22:36.279 side effects for ACE inhibitors. One involves 00:22:36.279 --> 00:22:39.019 the face. Angioedema. And the other involves 00:22:39.019 --> 00:22:42.339 teenagers. Let's do the face first. Angioedema 00:22:42.339 --> 00:22:45.019 is a rare but life -threatening allergic reaction 00:22:45.019 --> 00:22:48.000 where the lips, tongue, and airway can swell 00:22:48.000 --> 00:22:50.920 up. It can happen after the very first dose or 00:22:50.920 --> 00:22:53.099 after years of being on the drug. So if a parent 00:22:53.099 --> 00:22:55.319 calls and says his lips look weird and puffy 00:22:55.319 --> 00:22:57.980 after his new heart medicine. That is a 9 -on 00:22:57.980 --> 00:23:00.880 -1 call. That is a medical emergency. They need 00:23:00.880 --> 00:23:03.299 to go to the ER immediately. And the teenagers. 00:23:03.980 --> 00:23:07.339 Teratogenicity. It's a huge one. ACE inhibitors 00:23:07.339 --> 00:23:10.240 are a boxed warning for fetal toxicity. They 00:23:10.240 --> 00:23:12.480 are absolutely contraindicated in pregnancy. 00:23:12.660 --> 00:23:15.539 They cause fetal renal failure and death. Yes. 00:23:16.400 --> 00:23:18.559 So we're in pediatrics, and we often forget to 00:23:18.559 --> 00:23:20.619 think about this. But if you have a 16 -year 00:23:20.619 --> 00:23:22.940 -old girl with cardiomyopathy who is on Lisinopril. 00:23:23.140 --> 00:23:24.960 You have to have the awkward conversation. You 00:23:24.960 --> 00:23:27.000 have to. She cannot get pregnant while on this 00:23:27.000 --> 00:23:29.950 drug. It is category X. If she's sexually active, 00:23:30.069 --> 00:23:32.869 she needs reliable contraception. It is a mandatory 00:23:32.869 --> 00:23:34.930 part of your nursing education and documentation 00:23:34.930 --> 00:23:37.470 for all adolescent females of childbearing potential. 00:23:37.750 --> 00:23:41.450 It's a huge liability point. OK, Lasix and Lisinopril 00:23:41.450 --> 00:23:44.089 are sort of the daily maintenance crew. But sometimes, 00:23:44.369 --> 00:23:46.390 especially post -op, you need a heavy hitter 00:23:46.390 --> 00:23:49.029 to control acute hypertension. That's drug number 00:23:49.029 --> 00:23:53.069 five, hydrolazine. Hydrolazine is a direct acting 00:23:53.069 --> 00:23:55.650 vasodilator. It doesn't mess around with the 00:23:55.650 --> 00:23:58.730 whole RAAS system like ACE inhibitors do. It 00:23:58.730 --> 00:24:00.589 goes straight to the smooth muscle in the arteries 00:24:00.589 --> 00:24:03.269 and tells it to relax. And its effect is pretty 00:24:03.269 --> 00:24:06.549 rapid. Very rapid, especially the IV form. It 00:24:06.549 --> 00:24:08.890 decreases systemic resistance and lowers blood 00:24:08.890 --> 00:24:11.690 pressure fast. We use it a lot for post -op cardiac 00:24:11.690 --> 00:24:13.730 kids who come back from the OR with hypertension. 00:24:14.029 --> 00:24:16.410 But the body has a compensatory mechanism, right? 00:24:16.430 --> 00:24:19.150 You drop the pressure suddenly and the body panics. 00:24:19.250 --> 00:24:21.759 It does. It's called reflex tachycardia. The 00:24:21.759 --> 00:24:24.619 body's baroreceptors sense the sudden drop in 00:24:24.619 --> 00:24:26.960 pressure and they send an uh -oh signal to the 00:24:26.960 --> 00:24:28.980 brain. The brain then tells the heart to beat 00:24:28.980 --> 00:24:31.220 faster to try and bring the pressure back up. 00:24:31.319 --> 00:24:34.099 So you give IV hydrolazine, the blood pressure 00:24:34.099 --> 00:24:37.259 beautifully drops from 110 down to 90. But the 00:24:37.259 --> 00:24:40.140 heart rate spikes from 120 to 150. Is that considered 00:24:40.140 --> 00:24:43.619 a failure of the drug? No, it's an expected physiological 00:24:43.619 --> 00:24:45.940 response. We anticipate it. Yeah. But you need 00:24:45.940 --> 00:24:48.019 to monitor for it. And often these patients are 00:24:48.019 --> 00:24:50.079 also on a beta blocker, which helps to blunt 00:24:50.079 --> 00:24:52.940 that tachycardic spike. I found a weird nursing 00:24:52.940 --> 00:24:55.119 tip in the notes for hydrolazine regarding its 00:24:55.119 --> 00:24:57.980 interaction with metal. Yes. This is an old school, 00:24:58.279 --> 00:25:01.269 but vital piece of information. Hydrolazine can 00:25:01.269 --> 00:25:03.970 undergo a chemical change. It degrades and changes 00:25:03.970 --> 00:25:06.170 color if it sits in contact with metal for too 00:25:06.170 --> 00:25:08.670 long, like in a stainless steel medicine cup, 00:25:08.910 --> 00:25:11.150 or if drawn up with a metal needle and left to 00:25:11.150 --> 00:25:13.410 sit. So the rule is you don't pre -draw this 00:25:13.410 --> 00:25:15.269 medication and leave it on the counter for an 00:25:15.269 --> 00:25:17.710 hour. Never. You draw it up and you give it immediately. 00:25:17.990 --> 00:25:19.569 If you notice it's changed color, you have to 00:25:19.569 --> 00:25:21.930 toss it. It's a sign of chemical degradation 00:25:21.930 --> 00:25:24.549 and loss of potency. All right, that covers our 00:25:24.549 --> 00:25:27.170 failure fixers. Let's shift gears to section 00:25:27.170 --> 00:25:30.720 three, scenario specifics. We are moving away 00:25:30.720 --> 00:25:33.700 from general heart failure and looking at specific, 00:25:34.099 --> 00:25:36.559 terrifying events that happen with certain defects. 00:25:37.099 --> 00:25:39.779 Let's talk about the Tet spell. The hypersynotic 00:25:39.779 --> 00:25:42.880 spell. This is the hallmark of Tetralogy of Fallot, 00:25:43.240 --> 00:25:46.099 or TOF. Okay, quickly, what is the core problem 00:25:46.099 --> 00:25:48.700 in TOF? You have four defects, but the one that 00:25:48.700 --> 00:25:50.920 matters for spells is a narrowing of the pathway 00:25:50.920 --> 00:25:54.539 to the lungs. Pulmonary stenosis, combined with 00:25:54.539 --> 00:25:58.220 a big hole between the ventricles. A VSD. So 00:25:58.220 --> 00:26:00.720 describe the physiology of a spell. What is actually 00:26:00.720 --> 00:26:03.579 happening? So that pathway to the lungs is already 00:26:03.579 --> 00:26:06.279 narrow, but sometimes usually during an event 00:26:06.279 --> 00:26:09.079 that increases oxygen demand like crying, feeding, 00:26:09.240 --> 00:26:11.400 or having a bowel movement, the muscle right 00:26:11.400 --> 00:26:14.359 below that narrow valve, it's called the infundibulum, 00:26:14.700 --> 00:26:17.380 goes into a sudden severe spasm. It's like a 00:26:17.380 --> 00:26:19.660 fist closing around the hose to the lungs. That 00:26:19.660 --> 00:26:22.940 is a perfect analogy. It clamps shut. Now, deoxygenated 00:26:22.940 --> 00:26:25.019 blood coming into the right ventricle has nowhere 00:26:25.019 --> 00:26:27.279 to go. It can't get to the lungs, so it takes 00:26:27.279 --> 00:26:29.259 the path of least resistance, which is across 00:26:29.259 --> 00:26:31.799 the VSD into the left ventricle and out to the 00:26:31.799 --> 00:26:34.779 body. But this is blue, unoxygenated blood. Exactly. 00:26:34.940 --> 00:26:37.619 So the baby turns a deep, profound blue or purple 00:26:37.619 --> 00:26:40.769 almost instantly. Their oxygen saturation plummets 00:26:40.769 --> 00:26:43.250 into the 30s or 40s. It is terrifying to watch. 00:26:43.410 --> 00:26:45.589 We need a drug to break that spasm. Enter drug 00:26:45.589 --> 00:26:48.730 number six, propranolol. Propranolol is a non 00:26:48.730 --> 00:26:51.309 -selective beta blocker. It blocks the effects 00:26:51.309 --> 00:26:53.349 of adrenaline and the sympathetic nervous system 00:26:53.349 --> 00:26:56.269 on beta -1 receptors in the heart and beta -2 00:26:56.269 --> 00:26:58.450 receptors elsewhere. How does that help break 00:26:58.450 --> 00:27:00.609 the spell? By blocking the beta -1 receptors, 00:27:00.869 --> 00:27:03.910 it slows the heart rate and, crucially, it reduces 00:27:03.910 --> 00:27:07.589 the voice of contraction. It relaxes that spasming, 00:27:07.750 --> 00:27:10.150 infundibular muscle. It loosens the fist. The 00:27:10.150 --> 00:27:12.529 pathway to the lungs opens back up. It opens 00:27:12.529 --> 00:27:15.309 back up. Blood can flow to the lungs again, and 00:27:15.309 --> 00:27:17.910 the baby turns pink. So propranolol is usually 00:27:17.910 --> 00:27:20.750 given as a daily maintenance drug to prevent 00:27:20.750 --> 00:27:22.309 these spells from happening in the first place. 00:27:22.410 --> 00:27:25.150 Correct. But let's simulate the emergency. You're 00:27:25.150 --> 00:27:28.170 the nurse. A baby having a tet spell is in front 00:27:28.170 --> 00:27:30.450 of you. Do you run for the propranolol first? 00:27:30.750 --> 00:27:33.140 No. Absolutely not. The very first thing you 00:27:33.140 --> 00:27:35.680 do is change the physics of the situation. You 00:27:35.680 --> 00:27:37.640 put the baby in the knees to chest position. 00:27:37.960 --> 00:27:39.900 You take the baby's knees and you push them up 00:27:39.900 --> 00:27:42.319 firmly against their chest. Why does that work? 00:27:42.519 --> 00:27:45.380 It kinks the femoral arteries in the legs. This 00:27:45.380 --> 00:27:47.900 dramatically increases the systemic vascular 00:27:47.900 --> 00:27:51.759 resistance, or SVR. By making it harder for blood 00:27:51.759 --> 00:27:54.240 to flow down to the legs, you increase the pressure 00:27:54.240 --> 00:27:56.769 on the left side of the heart. This encourages 00:27:56.769 --> 00:27:59.329 the blood in the right ventricle to choose the 00:27:59.329 --> 00:28:02.250 now easier path to the lungs instead of shunting 00:28:02.250 --> 00:28:05.069 across the VSD. So it's a mechanical fix. It's 00:28:05.069 --> 00:28:07.170 a mechanical fix. So it's knees to chest, try 00:28:07.170 --> 00:28:09.609 to calm the infant, apply oxygen, and then you 00:28:09.609 --> 00:28:11.930 might give IV morphine, which also helps relax 00:28:11.930 --> 00:28:14.490 the spasm. Perpranolol would be more of a second 00:28:14.490 --> 00:28:17.130 line IV intervention in the acute spell, but 00:28:17.130 --> 00:28:19.759 its primary role is prevention. You mentioned 00:28:19.759 --> 00:28:21.839 propranolol is non -selective. That means it 00:28:21.839 --> 00:28:24.420 hits beta -1 and beta -2 receptors. Which is 00:28:24.420 --> 00:28:26.559 a major problem if your cardiac kid also has 00:28:26.559 --> 00:28:29.079 a history of asthma. Why? Because the beta -2 00:28:29.079 --> 00:28:31.519 receptors are what keep the airways the bronchioles 00:28:31.519 --> 00:28:34.210 open. If you block them with propranolol, you 00:28:34.210 --> 00:28:36.549 can trigger a severe bronchospasm, a massive 00:28:36.549 --> 00:28:39.230 asthma attack. So an absolute key nursing consideration 00:28:39.230 --> 00:28:41.470 is to check the patient's respiratory history. 00:28:41.809 --> 00:28:44.109 Cardiac kid plus asthma, propranolol is probably 00:28:44.109 --> 00:28:46.789 not the right choice. You'd want to use a cardioselective 00:28:46.789 --> 00:28:50.109 beta blocker instead, like metoprolol or atenolol, 00:28:50.349 --> 00:28:52.990 which primarily hits beta 1. There's one more 00:28:52.990 --> 00:28:55.430 tricky interaction with propranolol that is a 00:28:55.430 --> 00:28:59.630 favorite for exams, diabetes. Yes. Beta blockers 00:28:59.630 --> 00:29:02.769 mask the signs of hypoglycemia. Normally when 00:29:02.769 --> 00:29:04.650 your blood sugar drops your sympathetic nervous 00:29:04.650 --> 00:29:07.349 system kicks in. You get jittery, sweaty, and 00:29:07.349 --> 00:29:09.309 your heart races. That's your body's alarm bell 00:29:09.309 --> 00:29:11.880 telling you to eat. But beta blockers stop the 00:29:11.880 --> 00:29:14.539 jitters and the tachycardia. They block that 00:29:14.539 --> 00:29:17.500 whole response. Yes. So a diabetic child on propranolol 00:29:17.500 --> 00:29:19.680 could have their blood sugar drop to a dangerously 00:29:19.680 --> 00:29:22.500 low level without anyone noticing until they 00:29:22.500 --> 00:29:25.000 become lethargic or even have a seizure. So you 00:29:25.000 --> 00:29:27.319 have to be hypervigilant with blood sugar monitoring 00:29:27.319 --> 00:29:29.759 in that specific population. You absolutely do. 00:29:29.900 --> 00:29:31.599 OK, let's talk about the other big scenario, 00:29:32.019 --> 00:29:34.839 clots. Kids with complex heart defects are full 00:29:34.839 --> 00:29:37.240 of plastic tubes, artificial shunts, patches, 00:29:37.460 --> 00:29:39.839 and areas of sluggish blood flow. All of this 00:29:39.839 --> 00:29:42.740 is a recipe for thrombosis. Which brings us to 00:29:42.740 --> 00:29:46.440 heparin, drug number seven. Heparin is an anticoagulant. 00:29:46.799 --> 00:29:49.420 Its mechanism is that it potentiates the body's 00:29:49.420 --> 00:29:52.539 own natural anti -clotting factor, antithrombin 00:29:52.539 --> 00:29:55.819 the third. Right. It basically supercharges antithrombin 00:29:55.819 --> 00:29:58.299 the third, making it hundreds of times more effective 00:29:58.299 --> 00:30:00.920 at inactivating thrombin and other clotting factors. 00:30:01.380 --> 00:30:03.640 It doesn't break down existing clots, but it 00:30:03.640 --> 00:30:05.799 stops them from getting bigger and prevents new 00:30:05.799 --> 00:30:08.640 ones from forming. We use this a lot after surgeries, 00:30:08.819 --> 00:30:10.940 especially with palliative shunts like the BT 00:30:10.940 --> 00:30:13.980 shunt. A Blalock tossing shunt is a tiny Gore 00:30:13.980 --> 00:30:16.380 -Tex tube, maybe three or four millimeters wide, 00:30:16.880 --> 00:30:19.140 that connects an artery from the aorta to the 00:30:19.140 --> 00:30:21.619 pulmonary artery. It's a lifeline for babies 00:30:21.619 --> 00:30:24.579 who need more pulmonary blood flow. If that tiny 00:30:24.579 --> 00:30:28.160 tube clots off, the baby dies. Heparin is critical 00:30:28.160 --> 00:30:30.880 to keep it patent. The primary risk, obviously, 00:30:31.059 --> 00:30:33.390 is bleeding. But I want to focus on the fatal 00:30:33.390 --> 00:30:35.150 error warning mentioned in the sources. This 00:30:35.150 --> 00:30:37.049 is something that has tragically killed patients. 00:30:37.470 --> 00:30:39.990 The concentration error. This is one of the most 00:30:39.990 --> 00:30:43.190 feared medication errors in all of nursing. Heparin 00:30:43.190 --> 00:30:45.430 comes in vials that can look frighteningly similar 00:30:45.430 --> 00:30:47.410 but have vastly different strengths. You have 00:30:47.410 --> 00:30:49.569 the flush concentration. Which is very dilute. 00:30:49.730 --> 00:30:52.509 Maybe 10 units per ml or 100 units per ml. It's 00:30:52.509 --> 00:30:55.029 used just to keep IV and central lines from clogging 00:30:55.029 --> 00:30:57.470 up between uses. And then you have the systemic 00:30:57.470 --> 00:31:00.349 or therapeutic file. Which can be 1 ,000 units 00:31:00.349 --> 00:31:03.430 per ml. 5 ,000 or even 10 ,000 units per ml. 00:31:04.089 --> 00:31:06.890 That is a potential 1 ,000 -fold difference in 00:31:06.890 --> 00:31:09.250 concentration. And if you grab the 10 ,000 -unit 00:31:09.250 --> 00:31:11.450 vial thinking it's the 10 -unit flesh? You give 00:31:11.450 --> 00:31:15.069 a massive overdose. You effectively exsanguinate 00:31:15.069 --> 00:31:17.769 the patient internally. Their blood becomes unable 00:31:17.769 --> 00:31:21.390 to clot at all. In a tiny neonate, this is almost 00:31:21.390 --> 00:31:24.470 always fatal. It's caused well -publicized deaths. 00:31:24.990 --> 00:31:27.230 This is why heparin is a mandatory two -nurse 00:31:27.230 --> 00:31:29.130 check in almost every hospital in the country. 00:31:29.250 --> 00:31:31.509 It has to be. You have to physically get a second 00:31:31.509 --> 00:31:34.390 licensed person, show them the vial, read the 00:31:34.390 --> 00:31:36.349 concentration out loud, and show them your calculation. 00:31:36.549 --> 00:31:39.609 I have heparin, 10 ,000 units per mL. The order 00:31:39.609 --> 00:31:44.609 is for 100 units. I have drawn up 0 .01 mLs. 00:31:44.609 --> 00:31:46.890 They have to verify every step. And you can't 00:31:46.890 --> 00:31:48.849 rely on the color of the cap. Absolutely not. 00:31:49.529 --> 00:31:51.509 Manufacturers change cap colors all the time. 00:31:51.710 --> 00:31:53.589 You have to read the words on the label. If you 00:31:53.589 --> 00:31:55.549 do make a mistake or if the patient just starts 00:31:55.549 --> 00:31:57.470 hemorrhaging for other reasons while on heparin, 00:31:57.509 --> 00:32:00.130 is there an undo button? There is. It's protamine 00:32:00.130 --> 00:32:03.430 sulfate. That is the specific antidote for heparin. 00:32:03.789 --> 00:32:06.250 It binds directly to the heparin molecule and 00:32:06.250 --> 00:32:08.710 neutralizes it. You need to know where that is 00:32:08.710 --> 00:32:10.849 kept on your unit, because when you need it, 00:32:10.869 --> 00:32:12.670 you need it now. And what are you monitoring 00:32:12.670 --> 00:32:15.049 for a patient on a continuous heparin infusion? 00:32:15.329 --> 00:32:18.829 The APTT, or activated partial thromboplastin 00:32:18.829 --> 00:32:21.680 time. That lab value tells you how long it takes 00:32:21.680 --> 00:32:24.099 the blood to clot and you adjust the heparin 00:32:24.099 --> 00:32:26.880 drip rate up or down to keep the APTT within 00:32:26.880 --> 00:32:29.660 a specific therapeutic range. Okay, we are in 00:32:29.660 --> 00:32:32.660 the homestretch. Section four, the acquired heart 00:32:32.660 --> 00:32:35.859 disease meds. These are kids born with structurally 00:32:35.859 --> 00:32:38.400 normal hearts who get sick. We have a trio here. 00:32:38.640 --> 00:32:41.500 Kawasaki disease, rheumatic fever, and infective 00:32:41.500 --> 00:32:43.859 endocarditis. Right. These are inflammatory or 00:32:43.859 --> 00:32:46.359 infectious processes that attack the heart. Let's 00:32:46.359 --> 00:32:48.880 start with Kawasaki disease. This is the vasculitis 00:32:48.880 --> 00:32:51.400 known for the high fever, the rash, the strawberry 00:32:51.400 --> 00:32:53.859 tongue. The real danger with Kawasaki is not 00:32:53.859 --> 00:32:56.400 the rash or the fever. It's that the immune system 00:32:56.400 --> 00:32:59.119 launches a massive inflammatory attack on the 00:32:59.119 --> 00:33:01.519 blood vessels, and it has a scary affinity for 00:33:01.519 --> 00:33:03.819 the coronary arteries. The arteries that feed 00:33:03.819 --> 00:33:07.559 the heart muscle itself. Yes. It can cause coronary 00:33:07.559 --> 00:33:10.539 artery aneurysms weak, ballooning spots in the 00:33:10.539 --> 00:33:12.940 vessels. These can lead to blood quats, heart 00:33:12.940 --> 00:33:15.490 attacks, and sudden death even years later. And 00:33:15.490 --> 00:33:17.910 the treatment regimen for Kawasaki involves two 00:33:17.910 --> 00:33:21.089 key things, one of which is a drug we are rigorously 00:33:21.089 --> 00:33:23.970 taught never to give to children. Aspirin. Right. 00:33:24.569 --> 00:33:26.730 Every nursing student learns that giving aspirin 00:33:26.730 --> 00:33:29.349 to a child with a viral illness can cause Ray's 00:33:29.349 --> 00:33:31.509 syndrome, a devastating condition that causes 00:33:31.509 --> 00:33:34.190 litter failure and brain swelling. And that is 00:33:34.190 --> 00:33:37.569 absolutely true. But Kawasaki is the one major 00:33:37.569 --> 00:33:40.230 exception to that rule. The risk of a permanent 00:33:40.230 --> 00:33:43.809 coronary artery aneurysm is so high. and the 00:33:43.809 --> 00:33:46.269 anti -inflammatory and anti -platelet effects 00:33:46.269 --> 00:33:49.430 of aspirin are so beneficial that we accept the 00:33:49.430 --> 00:33:52.170 small risk of raise. So we give very high doses 00:33:52.170 --> 00:33:54.309 of aspirin initially to cool down the inflammation 00:33:54.309 --> 00:33:56.890 and then a low dose for a long time to prevent 00:33:56.890 --> 00:33:59.049 clots. Exactly. And the second part of the treatment 00:33:59.049 --> 00:34:02.410 is a massive dose of IVIG intravenous immunoglobulin. 00:34:02.490 --> 00:34:05.009 What's the thinking there? IVIG. is a product 00:34:05.009 --> 00:34:07.630 made from the pooled antibodies of thousands 00:34:07.630 --> 00:34:10.809 of blood donors. Giving a huge dose of it seems 00:34:10.809 --> 00:34:13.989 to reset or modulate the patient's own haywire 00:34:13.989 --> 00:34:16.449 immune system, stopping it from attacking the 00:34:16.449 --> 00:34:19.230 blood vessels. It dramatically reduces the incidence 00:34:19.230 --> 00:34:22.110 of coronary aneurysms. But there is a logistical 00:34:22.110 --> 00:34:24.650 catch with IVIG that's a big deal for pediatric 00:34:24.650 --> 00:34:28.500 nurses. It messes with vaccines. It does. Because 00:34:28.500 --> 00:34:31.159 IVIG is just a soup of antibodies, if you give 00:34:31.159 --> 00:34:34.639 a child a live vaccine, like the MMR for measles, 00:34:34.800 --> 00:34:36.920 mumps, rubella, or the varicella vaccine for 00:34:36.920 --> 00:34:39.239 chickenpox, right after they've received IVIG. 00:34:39.480 --> 00:34:41.780 The antibodies in the IVIG will just attack and 00:34:41.780 --> 00:34:43.780 kill the weakened vaccine virus. And the child's 00:34:43.780 --> 00:34:45.699 body never gets a chance to build its own immunity. 00:34:45.920 --> 00:34:48.320 The vaccine just won't take. So what's the rule? 00:34:48.519 --> 00:34:51.559 The rule is you must delay all live virus vaccines 00:34:51.559 --> 00:34:54.780 for 11 months after the IVIG infusion. This is 00:34:54.780 --> 00:34:57.019 a huge teaching point for parents at discharge. 00:34:57.230 --> 00:34:59.170 You have to make sure they understand why their 00:34:59.170 --> 00:35:01.469 child's vaccine schedule is being altered. Okay. 00:35:01.630 --> 00:35:04.010 Finally, let's touch on rheumatic fever and infective 00:35:04.010 --> 00:35:06.369 endocarditis. These are both bacterial in origin. 00:35:06.789 --> 00:35:09.590 Correct. Rheumatic fever is a post -infectious 00:35:09.590 --> 00:35:13.170 complication of untreated group A strep throat. 00:35:14.469 --> 00:35:17.429 Endocarditis is a direct bacterial infection 00:35:17.429 --> 00:35:20.380 of the heart lining or valves. The 80 -20 here 00:35:20.380 --> 00:35:22.420 seems to be about the duration of antibiotic 00:35:22.420 --> 00:35:24.699 therapy. These are not your typical five -day 00:35:24.699 --> 00:35:27.760 courses of amoxicillin. Not even close. For infective 00:35:27.760 --> 00:35:29.880 endocarditis, you have these clumps of bacteria 00:35:29.880 --> 00:35:32.519 called vegetations growing on a heart valve. 00:35:32.750 --> 00:35:35.610 It's incredibly difficult for antibiotics to 00:35:35.610 --> 00:35:37.989 penetrate that biofilm. These kids need four 00:35:37.989 --> 00:35:40.349 to eight weeks of high -dose IV antibiotics, 00:35:40.909 --> 00:35:43.909 usually something strong like penicillin G or 00:35:43.909 --> 00:35:46.789 vancomycin. So they are going home with a PICC 00:35:46.789 --> 00:35:49.230 line and home health nursing. It's a huge commitment 00:35:49.230 --> 00:35:51.369 for the family. And for romantic fever, the issue 00:35:51.369 --> 00:35:54.130 is preventing recurrence. If you've had it once, 00:35:54.369 --> 00:35:56.329 your heart valves can be damaged and you're very 00:35:56.329 --> 00:35:58.010 susceptible to getting it again with another 00:35:58.010 --> 00:36:00.460 strep infection. So these patients need long 00:36:00.460 --> 00:36:03.119 -term prophylaxis? Yes. They might be on monthly 00:36:03.119 --> 00:36:05.280 injections of long -acting penicillin until they 00:36:05.280 --> 00:36:07.940 are 21 years old, or sometimes even for life, 00:36:08.239 --> 00:36:10.179 to protect their heart valves from further damage. 00:36:10.480 --> 00:36:14.019 It's a huge burden. OK, so looking back at this 00:36:14.019 --> 00:36:16.260 entire roadmap, we've covered a lot of ground. 00:36:16.659 --> 00:36:20.179 We have the ductal duo. Alprostidyl and indomethacin. 00:36:20.840 --> 00:36:22.900 The opener and the closer. Watch the breathing 00:36:22.900 --> 00:36:24.880 for the opener. Watch the kidneys for the closer. 00:36:24.940 --> 00:36:28.519 Exactly. Then we have... The failure fixers, 00:36:28.920 --> 00:36:31.800 Lasix and Lisinopril. Watch the potassium. It's 00:36:31.800 --> 00:36:34.860 a seesaw. Lasix wastes it. Lisinopril saves it. 00:36:35.139 --> 00:36:37.840 And always, always check a potassium level. If 00:36:37.840 --> 00:36:41.780 a baby on digoxin starts vomiting. We have the 00:36:41.780 --> 00:36:44.059 scenario managers, proprinol for tet spells, 00:36:44.340 --> 00:36:46.820 heparin for clots. Knees to chest first for the 00:36:46.820 --> 00:36:49.420 spell. And read the vial out loud for the heparin. 00:36:49.599 --> 00:36:52.500 Twice. And finally, the acquired trio, where 00:36:52.500 --> 00:36:54.760 we break the aspirin rule for Kawasaki and give 00:36:54.760 --> 00:36:57.699 IV antibiotics for weeks on end. What is the 00:36:57.699 --> 00:37:00.360 big so what here? Why does this specific level 00:37:00.360 --> 00:37:02.940 of detail actually matter at the bedside? Because 00:37:02.940 --> 00:37:04.860 the margin for error in a three kilogram baby 00:37:04.860 --> 00:37:07.900 is non -existent. A misplaced decimal point in 00:37:07.900 --> 00:37:10.039 a dose calculation isn't just a paperwork problem, 00:37:10.119 --> 00:37:12.539 it's a stroke. It's renal failure. It's a dead 00:37:12.539 --> 00:37:15.179 baby. It's about anticipation. That's the word. 00:37:16.110 --> 00:37:18.750 If you know alprostedil causes apnea, you aren't 00:37:18.750 --> 00:37:20.530 staring at the monitor in shock when the alarm 00:37:20.530 --> 00:37:22.969 goes off. You are already standing there with 00:37:22.969 --> 00:37:25.650 the bag -salve mask in your hand. You move from 00:37:25.650 --> 00:37:28.869 being reactive to being proactive. That is what 00:37:28.869 --> 00:37:31.389 saves lives. And before we wrap up, I want to 00:37:31.389 --> 00:37:33.349 leave you with one final thought that really 00:37:33.349 --> 00:37:36.449 struck me while researching alprostedil. We treat 00:37:36.449 --> 00:37:39.389 these drugs like these very sterile industrial 00:37:39.389 --> 00:37:43.030 chemicals. But nature is incredibly efficient. 00:37:43.480 --> 00:37:46.280 Do you know where prostaglandins were first discovered? 00:37:46.579 --> 00:37:49.460 In seminal fluid. Hence the name, prostaglandin. 00:37:49.840 --> 00:37:51.739 It was first isolated from the prostate gland. 00:37:52.019 --> 00:37:54.239 The exact same molecule that biology uses for 00:37:54.239 --> 00:37:56.260 reproduction is the molecule we use to keep a 00:37:56.260 --> 00:37:58.840 blue baby alive until surgery. And it's the same 00:37:58.840 --> 00:38:01.320 molecule used in drugs like cavergect for adult 00:38:01.320 --> 00:38:03.380 erectile dysfunction. It's just a tool. It's 00:38:03.380 --> 00:38:05.900 just keys and locks. The body reuses the same 00:38:05.900 --> 00:38:07.980 key for different doors. It just makes you wonder 00:38:07.980 --> 00:38:11.360 what other off -label miracles are sitting in 00:38:11.360 --> 00:38:13.440 our pharmacy right now, just waiting for someone 00:38:13.440 --> 00:38:16.059 to figure out that a key for one condition fits 00:38:16.059 --> 00:38:19.099 a completely different lock somewhere else. It's 00:38:19.099 --> 00:38:21.980 a fascinating field. Biology is always smarter 00:38:21.980 --> 00:38:23.860 than we are. We're just trying to catch up to 00:38:23.860 --> 00:38:26.440 its designs. Keep your drips timed. Check your 00:38:26.440 --> 00:38:28.980 math twice. And trust your gut. We'll see you 00:38:28.980 --> 00:38:29.760 in the next deep dive.