Famous for being one of the “H’s and T’s,” cardiac tamponade is a life-threatening condition. But what exactly is tamponade?
How do I know if my patient is in tamponade and what do I do about it?
BSN, RN, CCRN-CMC
Medical News Today defines cardiac tamponade as “the accumulation of fluid around the heart muscle.”
As a result of this fluid accumulation, excessive pressure is placed on the heart. There is normally a small amount of fluid inside the pericardial sac to prevent the sac from adhering to the wall of the heart.
Eventually, there is so much pressure on the heart that it cannot fill and stretch the muscle fibers enough to produce an adequate stroke volume. The right ventricle is especially susceptible to tamponade, as it is less muscular than the left and therefore dependent on adequate filling.
When the right side of the heart fails, it cannot fill the left side which pumps blood to the major organs and tissues.
Essentially, the fluid in the pericardial sac collapses the heart and the patient loses pulsatile blood flow.
Medical experts at Medscape outline that if a patient goes into cardiac arrest from tamponade, they typically will have pulseless electrical activity (PEA) as their presenting rhythm.
If the fluid builds up slowly over time it can take a large amount of fluid to cause signs of the cardiac tamponade triad.
Conversely, the Canadian Journal of Cardiology notes that if the fluid develops quickly then symptoms of tamponade can develop from a relatively small amount of fluid.
In order to identify the signs, symptoms, and treatments available for the cardiac tamponade triad, it is essential that we cover what causes this fluid buildup in the first place.
The fluid that builds up around the heart may come from a number of different conditions.
A common cause of pericardial effusion – fluid in the pericardial sac that surrounds the heart – is pericarditis.
The Mayo Clinic defines pericarditis as the swelling and irritation of the tissue surrounding the heart. This inflammation triggers an immune response which can lead to a buildup of fluid in the pericardium.
Pericardial effusions can occur during or after procedures involving the heart or pericardium.
Coronary angiogram, pacemaker implantation, transcutaneous valvular procedures and heart rhythm procedures are some examples of interventions that may trigger a pericardial effusion.
Effusions develop periprocedurally from small perforations that may have been made or from an inflammatory response by the heart.
Pericardial effusions may develop from a ventricular rupture after a heart attack, or from an aortic dissection. In these cases, the fluid around the heart would be blood, a condition known as hemopericardium.
Online publication, Contemporary Oncology, highlights cancer as being an additional causative factor of fluid buildup due to its overproduction of non-functional cells, which can present as fluid.
In short, if this fluid is produced in the pericardial space it can lead to tamponade, which begins the cardiac tamponade triad.
The classic symptoms of the cardiac tamponade triad (also commonly referred to as Beck’s triad) are hypotension, elevated jugular venous distension, and muffled heart sounds, as highlighted by the American Heart Association (AHA).
The fluid around the heart muffles the heart sounds so they are more difficult to hear, and as the heart is compressed it cannot fill as well, leading the fluid back up into the jugular veins.
With the hypotension, a narrow pulse pressure is common in tamponade.
As the pressure increases around the heart, the diastolic pressure increases as the stroke volume decreases. This leads the systolic and diastolic numbers to come closer together.
If the patient has a pulmonary artery catheter, you can see equalization of pressures, where the pulmonary artery pressure, right atrial pressure, and systemic blood pressure all come close to equal.
Another sign that can be seen is pulsus paradoxus; which is a periodic raise and drop in the blood pressure that correlates with the respiratory cycle.
When the patient breathes in, pressure in the chest increases and exerts more pressure on the heart, which lowers the blood pressure. When they breathe out, the intrathoracic pressure decreases and the blood pressure increases back to baseline.
Pulsus paradoxus is most easily seen on an artline waveform but can be seen on a good quality pulse oximeter waveform as well.
If you think you may be seeing pulsus paradoxus, decreasing the speed of the tracing – if your monitor allows – makes the cyclical changes easier to visualize.
Confirmation of cardiac tamponade is done with an echocardiogram. Using an ultrasound probe, the fluid in the pericardial sac can be visualized (2).
The best initial intervention for cardiac tamponade is an IV fluid bolus.
Bolusing fluids fills the heart to promote more stretching of the muscle fibers to allow for a stronger contraction.
Basically, the fluids help to exert pressure against the walls of the heart from the inside, which helps to offset the pressure being exerted by the fluids on the outside of the heart.
A fluid bolus is a great temporizing measure, but the curative treatment is a pericardiocentesis. During pericardiocentesis a needle is inserted into the pericardial sac and the fluid is drained.
Pericardiocentesis is typically done with ultrasound or echo guidance to ensure the needle is being inserted where the fluid collection is.
Removing the fluid from the body relieves the pressure on the heart, and cardiac function returns to normal very quickly. You should see improvement in the patient’s blood pressure almost immediately when the fluid is removed.
Cardiac tamponade is a life-threatening condition caused by fluid building up around the heart.
The cardiac tamponade triad presents with hypotension, a narrow pulse pressure, JVD, muffled heart sounds and potentially pulsus paradoxus. The condition is confirmed with an echo.
The best treatments for a confirmed tamponade are IV fluids and pericardiocentesis.
Understanding what happens in tamponade helps the symptoms to make more sense; and knowing what to do to diagnose and treat it can be lifesaving.
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