Performing A Pericardiocentesis In Patients With Cardiac Tamponade
What is a Pericardial Effusion
A pericardial effusion is a collection of fluid that collects between the walls of the heart and the pericardium. This area is called the pericardial space and typically contains a small amount of fluid which lubricates the heart. An abnormal accumulation of fluid in this space is known as a pericardial effusion. Pericardial effusions can be chronic (accumulate over weeks, months, years) or acute (rapid accumulation of blood in the setting of trauma). Pericardial effusions that accumulate quickly can lead to cardiac tamponade. Cardiac tamponade results in an equilization of pressures across all 4 chambers of the heart leading to right ventricular collapse, decrease preload, and decreased cardiac output. Cardiac tamponade is an life-threatening emergency that can lead to severe cardiac dysfunction and death if not quickly addressed.
Diagnosing Tamponade on Ultrasound
The diagnosis of cardiac tamponade can be made on bedside ultrasound. You first need to visualize the heart in any view (subxiphoid, parasternal long, apical) and evaluate for a pericardial effusion. A pericardial effusion is best visualized on the subxiphoid view. Fluid has the appearance of an anechoic area on ultrasound. In the case of a pericardial effusion, the anechoic area will encircle the heart. You will be able to visualize the anechoic fluid between the heart and the pericardium which both appear bright white.
Steps to diagnose cardiac tamponade:
- Evaluate for the presence of a pericardial effusion
- Evaluate for right ventricular collapse
- Evaluate for a dilated IVC
Performing a Pericardiocentesis
For patients with cardiac tamponade an emergenct pericardiocentesis should be performed to drain the fluid and improve cardiac output.
Items needed for performing a pericardiocentesis include:
- ultrasound machine
- pericardiocentesis tray or long needle with syringe
Performing the procedure:
- The procedure can be performed using any approach (parasternal, apical, subxiphoid) but there is a higher risk of injuring the coronary vessels while performing the procedure using a parasternal approach.
- Using ultrasound visualize the pericardial effusion and advance the needle, aspirating as you advance. Once you get into the pericardial space you should be able to aspirate the pericardial effusion. Disconnect the syringe, keeping the needle in place and advance a guide wire.
- Confirm that the guide wire is in the correct place with ultrasound. Advance the dilator over the guide wire, dilating the soft tissue.
- Remove the dilator, advance the catheter over the guide wire, and remove the guide wire. Secure the catheter in place.
Tips and Tricks
- Place the patient on a cardiac monitor prior to performing and throughout the procedure!
- Always keep the needle in plane by using a sagittal or long-axis approach!
- the entire length of the needle should be visualized on ultrasound while doing the procedure to visualize important underlying structures including the ventricular walls.
- Go where the largest pocket is!
- Pericardial effusions can become loculated meaning the largest collection of fluid is not always in the posterior aspect of the heart when lying supine. Perform an ultrasound in multiple views to visualize where the largest pocket is prior to doing the procedure.