When to Suspect Cardiac Tamponade

Las Vegas Fire Rescue was called to a residence in Las Vegas for a 50-year-old man who reported shortness of breath lasting two days. On arrival, paramedics found the patient seated on the side of the bed and in acute distress.

They completed a primary assessment and administered 100% oxygen. Vital signs revealed a blood pressure of 50 systolic by palpation, a pulse of 52 and respirations of 28. The patient was afebrile. The SpO2 was 92%, and the 12-lead ECG showed a sinus bradycardia with no ST-T wave changes.

The secondary assessment revealed bibasilar rales and minimal peripheral edema. The patient had a healing surgical incision over his sternum. He reported having had an aortic valve replacement and an aortic root replacement several weeks prior for severe aortic insufficiency and an aortic dissection. He also had a history of hepatitis C.

The EMS crew thought the findings and vital signs suggested cardiac tamponade. They rapidly completed their assessment and transported the patient to the University Medical Center (UMC) in Las Vegas. A saline lock was inserted into the dorsum of his left hand while en route. He remained stable during transport.
In the adult medicine emergency department (ED), the patient was promptly evaluated. He remained in acute distress, still orthopneic and dyspneic. Vital signs were: blood pressure 64/48, pulse 52, respirations 28, temperature 97.1° F and SpO2 92%. Physical exam revealed diminished breath sounds in the right base, muffled heart sounds and the presence of jugular venous distension (JVD).

The patient had 1+ pitting edema of the lower extremities. The ECG revealed a sinus bradycardia but was otherwise normal. The chest X-ray showed a significantly enlarged heart (cardiomegaly) and fluid (pleural effusion) in the right chest. The emergency physicians performed a bedside ultrasound that revealed a large amount of fluid around the heart. Based upon this and the physical exam findings, a diagnosis of cardiac tamponade was made.

Using ultrasound guidance, a needle was inserted into the pericardial sac. ED physicians placed and secured a pigtail catheter into the pericardial sac and removed 500 mL of fluid. The patient rapidly improved. His blood pressure increased to 130/79, heart rate increased to 71, and SpO2 improved to 97%. Once stabilized, the patient was admitted to the cardiac care unit.

A cardiovascular surgeon evaluated the patient and felt that the catheter placed into the pericardial sac by the emergency physicians was adequate. The catheter remained in the pericardial sac for several days. No additional fluid developed, and the catheter was removed. In addition to the pericardial drainage, 850 mL of fluid was also drained from the patient’s left chest through a separate catheter. The patient remained stable and was discharged in improved condition.

Cardiac tamponade is an uncommon–but life-threatening–condition. It occurs when increased fluid (pericardial effusion) develops within the pericardial sac. The pericardial sac, which surrounds the heart, normally contains a small amount of fluid (pericardial fluid) that primarily serves as a lubricant.

However, there are some conditions that will cause an increase in the amount of fluid within this sac. These include such nontraumatic conditions as malignancies (cancer), infections (AIDS, tuberculosis) and renal failure.

Trauma, primarily low-velocity penetrating trauma (e.g., stab wound), can also cause the pericardial sac to fill with blood and subsequently cause cardiac tamponade. Cardiac tamponade can occur following thoracic surgery, as it did in this case.
As the volume of fluid or blood within the pericardial sac increases, so does the intrapericardial pressure. The pericardial sac is tough and fibrous, and has little capacity to expand. As fluid accumulates, the sac will eventually reach a point where it inhibits the filling and pumping actions of the heart, ultimately reducing the cardiac output and resulting in shock.

The signs and symptoms of cardiac tamponade are more striking when the tamponade occurs rapidly, as in trauma. They’re less striking when they occur slowly. Typically, these patients will have tachycardia, a low systolic pressure and a low pulse pressure. The pulse pressure is the difference between the systolic and diastolic pressures. This patient had a pulse pressure of 16 mmHg (normal is 30—40 mmHg).

In patients with a regular heart rhythm, pulsus paradoxus may also be present. Pulsus paradoxus is an exaggeration of the normal decrease in systolic blood pressure that occurs with respiration (due to changes in the pressure within the chest). It’s usually defined as an inspiratory fall in the systolic blood pressure of greater than 10 mmHg.

On physical examination, patients with cardiac tamponade may exhibit frank (rapid and significant) shock. They’ll often have JVD and muffled heart sounds. Hypotension is common. In fact, the findings of JVD (due to decreased right ventricular filling), hypotension and muffled heart sounds are referred to as “Beck’s triad” and considered indicative of cardiac tamponade. This patient clearly had findings consistent with Beck’s triad.

Treatment is directed at decreasing intrapericardial pressure by withdrawing fluid from the pericardial sac. Typically, a needle is inserted into the pericardial space and enough fluid withdrawn to normalize vital signs. This process, called a pericardiocentesis, is dangerous. There’s a risk of penetrating the heart, a coronary artery or other structures.

Dysrhythmias are also common–especially if the needle tip touches the heart itself. The procedure is made safer by using ultrasound imaging to visualize the anatomy and direct needle insertion.

In nontraumatic cardiac tamponade, a pigtail catheter is often placed in the pericardial space to allow and monitor drainage. Sometimes a surgical opening (a pericardial window) is made in the pericardial sac to prevent future fluid accumulation and subsequent tamponade.

With trauma, there’s typically a wound in the heart that must be repaired surgically. In this situation, the pericardiocentesis will provide temporary improvement until the patient can be taken to the operating room for repair of the cardiac laceration.

Teaching Points
Cardiac tamponade is uncommon. However, prompt recognition and treatment can be lifesaving. EMS personnel should maintain an index of suspicion for this condition. The most common traumatic cause is low-energy penetrating chest trauma. It can also occur in non-traumatic conditions, such as cancer.
It’s been estimated that 10% of patients with metastatic cancer will develop cardiac tamponade. It can also occur with serious infections, such as AIDS and tuberculosis, and can be seen, as occurred in this patient, as a complication of cardiac surgery.

Any patient who’s hypotensive and has a narrowed pulse pressure should be evaluated for the possibility of cardiac tamponade. It’s difficult to hear heart sounds in the field. But, if conditions are right, try and auscultate heart sounds. If they’re distant or muffled, this suggests a pericardial effusion and possible cardiac tamponade.

This patient slowly developed a pericardial effusion that resulted in cardiac tamponade as a result of extensive cardiac surgery. The EMS personnel were summoned when the patient’s shortness of breath became worse. Paramedics found the patient hypotensive with a narrowed pulse pressure and suspected cardiac tamponade. In the ED, the patient was evaluated and cardiac tamponade confirmed. A pericardiocentesis was performed, and the patient stabilized. He was admitted and ultimately recovered.

This case again demonstrates that EMS is an essential part of the patient care continuum. A high index of suspicion and proper prehospital and emergency department treatment in this case was lifesaving. JEMS

This article originally appeared in June 2010 JEMS as “A Fluid Situation:Patient suffers from uncommon cardiac tamponade”.

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