Hypovolemia is a potentially fatal condition and is always considered a medical emergency. Treating the underlying reason for the hypovolemia, as well as keeping the patient stable provides the best outcome. Generally speaking, treatment consists of replacing fluid loss, and monitoring the patient's heart rate and blood pressure. Low blood pressure is common during hypovolemia and must be aggressively treated, usually with vasopressors. Dopamine, one of these pressors, has a complex role in the treatment process.
Hypovolemia
Hypovolemia is a condition that develops when your body does not have enough fluid volume to maintain proper bodily functions. Hypovolemia can result from either blood loss or fluid loss. Blood loss is often the result of a severe external wound -- like a gunshot or stab wound -- or an internal hemorrhage. However, severe dehydration usually causes fluid loss. Illnesses that cause vomiting, diarrhea or a combination of the two are the most common culprits. The lack of fluid seen in hypovolemia can lead to circulatory collapse, which usually presents with low blood pressure and an abnormally fast heart rate. Immediate treatment is necessary to prevent shock and eventual death.
Dopamine and Hypovolemia
Dopamine is a vasopressor commonly used to treat certain kinds of shock. It works by constricting the blood vessels, causing a rise in blood pressure. Dopamine is typically contraindicated in patients with hypovolemia. Patients experiencing fluid loss usually already have an abnormally fast heart rate. Dopamine also speeds up the heart rate. The combination can cause potentially fatal arrhythmias to occur. Furthermore, dopamine can cause gangrene if given in the presence of hypovolemia, according to a case report published in the July 2003 issue of "Turkish Journal of Trauma & Emergency Surgery."
Exceptions
Dopamine is occasionally used to treat low blood pressure arising from hypovolemia under very specific circumstances. If, after the patient has been completely hydrated and treated with other vasopressors, his blood pressure is still unresponsive, dopamine may be considered. In rare cases, dopamine is used as a last ditch effort in patients who are extremely close to death and in which all treatment options have been exhausted -- even if they are not fully hydrated.
Alternatives to Dopamine
Epinephrine, phenylephrine and norepinephrine are popular alternatives to dopamine, particularly because they carry less side effects and complications. Like dopamine, these vasopressors work by stimulating G-protein receptors, which increases contractility. Dobutamine may also be used, especially if cardiac problems, such as congestive heart failure, are present as well. Occasionally, amrinone is used in combination with one of the aforementioned pressors.
