Hypotension, or low blood pressure, is a condition in which the blood pressure is below normal. While a slightly low blood pressure may not pose a health risk, very low blood pressure can lead to organ damage and death. Dopamine is an IV medication given to patients who cannot maintain a normal blood pressure on their own.
Causes of Hypotension
According to Medical News Today, hypotension is defined as blood pressure below 90/60. When blood pressure continues to drop, blood is not able to circulate through the body and deliver oxygen to all the organs. Some common causes of life-threatening hypotension include internal bleeding, severe trauma or injury to the body, heart disease, and septicemia, in which bacteria invade the blood. If not treated, these can lead to shock and death. If you have a slow enough heart rate, this can also cause your blood pressure to drop, according to the American Heart Association.
How Dopamine Works
If you have low blood pressure due to septic shock, fluids such as IV saline should be given before any drugs to raise the pressure. IV fluids may be all that is needed to raise your pressure. When this fails, vasopressors such as dopamine may be needed, according to the Institute for Healthcare Improvement (IHI) . Vasopressors work by causing the blood vessels to constrict, therefore increasing blood pressure. According to the University of Illionois at Chicago College of Pharmacy, dopamine, along with norepinephrine, is a first-line drug for treating hypotension. Dopamine increases your heart rate and the amount of blood your heart pumps in one minute.
Dopamine Administration and Monitoring
According to the IHI, dopamine is a potent drug which may only be given in an ICU setting, where vital signs and heart rhythm are continuously monitored. Dopamine must be delivered on an IV pump programmed to deliver the drug at a precise rate, which can be titrated up or down based on how well your blood pressure responds. Measuring blood pressure with an arterial line gives constant blood pressure readings in real time. An arterial line is a special catheter placed in the radial artery on the wrist and attached to a monitor.
Considerations
Urine output is a good indicator of how well vital organs are functioning. Rx List recommends starting dopamine before urine output, cardiac function and blood pressure significantly deteriorate. Administering dopamine before urine output drops too much results in a better prognosis. Very low doses of dopamine may be given to increase your urine output without having to administer large volumes of IV fluids.
Cautions
Dopamine is extremely potent and should only be given in an ICU setting where your blood pressure and other vital signs can be properly monitored. It should be diluted in 250 mL or 500 mL of a suitable IV solution. Once mixed, it is stable for at least 24 hours, according to Rx List. It must be given on a programmable IV pump to avoid an accidental bolus.
Current Trends in Shock
According to Sciencedaily.com, an article in the March 4, 2010 issue of the New England Journal of Medicine reported that a study in Erasme University Hospital in Belgium compared dopamine and norepinephrine in shock patients. At 28 days there was no overall difference in death rates. But patients who received dopamine had almost twice as many arrhythmias as patients whose shock was treated with norepinephrine. This study challenged long-standing guidelines which call for dopamine as the first drug of choice for certain types of shock.
References
- American Heart Association: Low Blood Pressure
- Medical News Today: What is Low Blood Pressure? What is Hypotension?
- The Institute for Healthcare Improvement: Apply Vasopressors for Ongoing Hypotension
- University of Illinois at Chicago College of Pharmacy:
- Rx List: Dopamine
- Science Daily: Safety Data Favor Norepinephrine Over Dopamine for Shock
