Our cyanotic newborn

Let’s continue with the case presentation of our cyanotic newborn and what workup we might consider doing in helping us to focus first of all to distinguish this cyanotic congenital heart disease from other causes of cyanosis. Looking at these parameters, oxygen saturation, arterial blood gas, doing the hyperoxic test – some of the other laboratory studies that could be helpful would be hemoglobin in terms of oxygen carrying capacity. If a patient is severely anemic then he may not reflect the degree of desaturation by observation of his cyanosis. On the other hand, babies that are polycythemic sometimes look more cyanotic than they actually are de-saturated. The glucose and calcium are helpful as baselines as we will want to intervene and help this baby with its management. The chest x-ray can be a helpful clue in distinguishing the form of congenital heart disease with which we are dealing. To emphasize this, the early cardiac intervention; we are very concerned with babies with cyanotic congenital heart disease in that they can have a rapidly deteriorating course, as we will see in just a moment. The echocardiogram is an important part of the assessment, usually in the hands of the pediatric cardiologist. But we had transferred to us last night a baby with cyanotic congenital heart disease in whom the neonatologist had ordered the echo and made the appropriate diagnosis and fixed the baby up with the appropriate management and sent him off to us. This may be a typical course of this baby with cyanotic congenital heart disease. They often present late night, early morning, when you are the primary care person out there all by yourself, trying to figure out what’s going on. But let’s say this baby has an oxygen saturation of 72% when you first see him, with these arterial blood gases, but he progressively de-saturates with time. As he de-saturates he also becomes more acidemic. So again, not an unusual course for these babies with cyanotic congenital heart disease and therefore our stress on the urgency of recognizing them and early management.

So what are the goals, as far as the primary care physician in early management of these babies with cyanotic congenital heart disease? Well, treatment goals are to decrease or at least to check the level from progression of hypoxemia and to decrease the acidemia. The question is, how can you as a primary care physician intervene to implement these treatment goals in this early management? With regards to the hypoxemia, to increase pulmonary flow, increase mixing or to increase oxygen transport, are the potential ways of managing the hypoxemia. With regards to the acidemia, so reduce the hypoxemia usually is key to reducing the acidemia. To support the cardiac output. Often as these babies become more hypoxemic the myocardium suffers and they have decreased cardiac output. So to support the cardiac output can be helpful in correcting the acidemia. Also, to directly work at correcting the base deficit may be an important part of the management.

Now, how do you do these? How do you implement this management? Well, to increase pulmonary flow we can use prostaglandin E infusion to increase pulmonary flow. As a result of increasing pulmonary flow and any sorts of mixing, then you can potentially increase the systemic saturation as well. As far as oxygen transport is concerned, by hemoglobin, then if indicated certainly if the baby is a bit on the anemic side, then to give packed red blood cells. We use as sort of an indicator a hematocrit of 40. If the baby’s saturation is less than 80% then we try to achieve a hematocrit of at least 40% to enhance oxygen transport. If the baby, as a result of the hypoxemia and acidemia, is showing signs of compromised cardiac output then inotropic support, usually in the form of low-dose dopamine or dobutamine, can be very helpful in the early management. Correcting any deficits in terms of serum glucose or calcium -again, to enhance the myocardial function – can be important parts of the management as well. Sodium bicarb if indicated with severe acidemia and if you are not correcting the acidemia by these other measurements.

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