Welcome back. In previous modules, you've learned a lot about the evaluation of cardiac and respiratory status in newborns. In this module, we'd like to demonstrate how to use that information to make a diagnosis. Maybe you watch crime shows on TV. You can think of an illness as a crime to be solved. In order to get to the bottom of the crime, you first need to gather facts and evaluate them as clues to the situation. You then decide if these clues taken together, form a recognizable pattern that can point you to the solution of the problem. Finally, you have to present your evidence in a manner that convinces others of the correctness of your conclusion. Using this comparison, patient history and physical exam findings will be the clues. The solution of the problem will be the diagnosis. Your patient and their family will be the judge and the jury. Everyone would be convinced of the accuracy of your diagnosis, if the interventions that you prescribe help the patient to recover. You will watch as Dr. Gold and I demonstrate how to approach clinical scenarios regarding heart and lung health in newborn babies. Okay, here's the first case. A baby boy is born at term. His mother had care in another state and has no prenatal records available. She's 30 years old, has been pregnant two other times and has two healthy children at home. She tells you that she had several visits to an obstetrics clinic. She states that she was healthy throughout her pregnancy, took vitamins as prescribed, and did not use any other medications, illicit drugs or alcohol. Baby is born by a normal spontaneous vaginal delivery. His weight was three kilos, just right for a full-term baby. He cried vigorously right after delivery and was placed on his mother's chest. He breastfed for 15 minutes and cuddled for a while longer. The nurse examined him when he was two hours old and discovered that he looked blue. What would you do? Well, it's not unusual for newborn to have blue hands and feet at this age. We call that acrocyanosis. Is that the pattern of blueness that the nurse is seeing in this baby? His hands and feet are blue, but he also appears to have a blue tinge to his lips and his tongue. You're describing central cyanosis, that is not normal after the first few minutes of life. It's an indication of hypoxia or insufficient oxygen in the bloodstream. I would be concerned and wanted to perform a pulse oximetry test. This is a way in which I would get a sense of how much oxygen he has in his blood. By two hours of age, I would anticipate baby would have an oxygen saturation of at least 90 percent. This would mean that 90 percent of his red blood cells were carrying oxygen. I would place a pulse oximetry probe on the baby's right wrist. This location would give me a clue about what the oxygen is like in his most important organs, his heart and his brain. I would check his pulse against the pulse value displayed on the oximeter to be sure that the reading is correct. Good idea. When you do that, you find that the baby has an oxygen saturation of 82 percent. It seems that he really does have low oxygen. What does that mean to you? Well, there are two main categories of illness that can cause low oxygen in a baby, pulmonary or lung and cardiac or heart. It could be that his lungs are not getting enough oxygen to his bloodstream or that his heart is not keeping oxygenated and unoxygenated blood from mixing. The easiest way to determine if the heart or lungs are the source of hypoxia is to see what happens when you give the baby oxygen. This is known as the hyperoxia test. It is very easy to do. We have checked the baby's oxygen when he's breathing room air. Next, we will place him in an oxyhood and deliver 100 percent oxygen for 10 minutes and check the pulse oximetry reading again. If this saturation has improved substantially, we would know that the baby has lung disease. If there's little or no improvement, the source of the problem is more likely a malformation or defect of the heart, meaning congenital heart disease. Do you mean that all congenital heart diseases caused low oxygen? No, not all, but the critical congenital heart diseases do. These are a subset of congenital heart disease that require intervention in the first month of life in order to avoid death or severe consequences. I wonder if there are other clues about the nature of the heart disease? Does the baby have a normal cardiac exam? I thought you would never ask. Baby has a heart murmur. It can be easily heard when you place the stethoscope on his chest. When you place your hand over his heart, you can feel the vibration. I should have checked the heart sooner. I would've still want to do the hyperoxia test though. The heart has to make some changes in its anatomy immediately after the baby is born. While the fetus is in the womb, very little blood goes to the lungs. Instead, it gets pumped to the placenta. After birth, half gets sent to the lungs. During the transition period while these changes are happening, newborns often have heart murmurs. The hyperoxia test helps me to distinguish the life-threatening murmurs from the others. The murmur that you describe is most likely related to a malformation and not to simple transition. Are you certain that this baby has serious heart disease? How can you find out for sure? The way to truly diagnose a cardiac malformation is to check an echocardiogram. This is an ultrasound of the heart. But it has to be performed by a trained technician and read by a cardiologist. It's expensive, but necessary in this case. If there was not an echocardiogram in the first center, the baby will have to be sent somewhere else in order to see a cardiac specialist. By the way, while we're talking, what's happening to the baby? So the nurse tells me that the baby's breathing comfortably, but that his saturation is now down to 75 percent. This is just what I was worried about. His heart is not keeping oxygenated and unoxygenated blood separated. The oxygen going to his tissues is not adequate for them to function well. We need to get them to a cardiac specialist as quickly as possible. What do you think his diagnosis is? This baby has critical congenital heart disease. As a general pediatrician, I can't make a more precise diagnosis than that. The important thing now is to get them to somebody who can do specific imaging and intervene, in order to improve his circulation and oxygenation.