Cardiogenic shock is a medical emergency that requires urgent treatment to prevent irreversible damage to vital organs and loss of life. Emergency life support is given to provide oxygen and intravenous fluids and medications are administered to restore blood flow and raise the blood pressure.
Treatment is then focused on repairing the damage caused to the heart and other organs.
An outline of how a patient is treated for cardiogenic shock is given below:
- On admission to hospital, the patient is catheterized and the amount of urine they pass is recorded.
- An intravenous line is made, usually via a vein in the arm. However, veins in the arms may be difficult to find and a line may need to be introduced via a vein in the neck, in which case it is called a central venous line.
- The patient is monitored for blood oxygenation using a pulse oximeter and if necessary, the airway opening is maintained using endotracheal intubation. Oxygen is directly delivered to the airways of the patient. Some patients may develop respiratory failure and require mechanical ventilation.
- Blood samples are sent to the laboratory for assessment of arterial blood gas, electrolytes, blood counts and biochemical parameters.
- Electrolyte abnormalities should be corrected. Low blood levels of potassium or magnesium can damage the heart, creating abnormal ventricular rhythms. Acidosis is another dangerous condition that requires prompt treatment.
- Pain and anxiety can be relieved with morphine or fentanyl. Fentanyl is preferred over morphine if the systolic blood pressure is too low.
- In cases of heart attack or myocardial infarction, agents such as nitrates, beta-blockers, and angiotensin-converting enzyme inhibitors are normally used. However, in patients with cardiogenic shock these may further lower blood pressure and should not be used until the patient stabilizes.
- Drugs that increase the pumping capacity of the heart such as dopamine and dobutamine are called inotropic drugs. Dobutamine is a selective beta1-adrenergic receptor agonist that increases the cardiac output without significantly changing the heart rate or resistance of the peripheral vascular networks. Dobutamine is the drug of choice in patients with a systolic pressure higher than 80 mmHg.
- Dopamine exerts direct effects on the heart via beta 1 receptors present on cardiac myocytes and indirect effects by releasing norepinephrine. This increases the heart rate and raises the blood pressure. The use of dopamine is preferred when the systolic pressure is less than 80 mmHg. Other agents that stimulate the heart include phosphodiesterase inhibitors amrinone and milrinone.
- Patients with myocardial infarction need thrombolytic therapy to break down clots.
Reviewed by Sally Robertson, BSc