Introduction to Bedside Transthoracic Echocardiography (TTE) for the Critical Care Provider
This content is intended to introduce critical care providers to the fundamental techniques of bedside transthoracic echocardiography (TTE). It is not a comprehensive echocardiography course and does not confer certification. Rather, it serves as a starting point for developing echocardiographic skills, expanding clinical insight, and encouraging further training.
TTE offers valuable diagnostic information at the bedside, particularly in the assessment of cardiac function, volume status, and hemodynamic instability. While transesophageal echocardiography (TEE) remains a vital tool in certain intraoperative and ICU settings, TTE can be performed noninvasively and rapidly, providing insight into wall motion abnormalities, gross valvular pathology, pericardial effusions, and more.
Core Views and Equipment Considerations
There are four standard cardiac views commonly utilized in bedside TTE, beginning with the apical four-chamber view. These views are especially relevant to anesthesiology and critical care practice. Imaging requires a phased-array probe with a small footprint and depth capabilities of 10–20 cm. Standard linear and curved array probes are generally inadequate for cardiac windows.
Several structured protocols exist, including the FATE (Focused Assessed Transthoracic Echo) protocol, often integrated into broader assessments like the RUSH (Rapid Ultrasound in Shock and Hypotension) exam. While the specific protocol is flexible, the underlying objective remains the same: to efficiently obtain and interpret images that answer focused clinical questions—for example, evaluating left ventricular systolic function in suspected cardiogenic shock.
Clinical Application
TTE views should be selected and interpreted with a specific clinical question in mind. While advanced measurements such as pressure calculations are available, they may be impractical or unnecessary in acute care settings. The primary goal is to guide immediate clinical decisions in unstable patients.
Tips for Scanning
Use small, deliberate probe adjustments.
Be mindful of factors that degrade image quality, such as obesity, lung inflation, or poor positioning.
Practice on healthy individuals in ideal settings before transitioning to critically ill patients.
Always correlate echocardiographic findings with the clinical presentation—ultrasound should complement, not replace, clinical judgment.
To perform this exam place the probe in the 3rd-4th intercostal space just lateral to the left sternal border. The probes direction indicator should be directed towards the right shoulder. It is the only view that requires this right favored orientation. Maneuver the probe to reveal the image that should include septum, RVOT, left atrium and left ventricle in long axis, the aortic and mitral valve, descending thoracic aorta, and coronary sinus at the bottom of the image. The descending aorta in the deep portion of the image. This should be noted as fluid collections anterior (superficial) to the level of the descending aorta should be considered as pericardial in nature. Whereas fluid collection posterior (deep to) the descending aorta should be considered plural in nature. Good image criteria should include having the septum in a well defined horizontal plane, and the aortic and mitral valves should be easily seen. Generally the apex of the left ventricle is not seen in this image. This view is good for observing aortic stenosis and evaluation of regurgitation with application of the Doppler. Not a good choice for right ventricular structure or function evaluation. It's important that the depth setting is such that the area posterior to the heart can be seen. Failure to image the posterior space will prevent the provider from ruling in a pleural effusion. Its recommended that you orient yourself and organize the structures to be sure you recognize them. Good for:
LV and LA gross function, mitral, aortic valves. LVOT for calculation of stroke volume and cardiac output
Pleural vs pericardial fluid imaging
Apical Four-Chamber View
The apical four-chamber view is a highly valuable transthoracic echocardiographic (TTE) window for providers across multiple disciplines. This view provides simultaneous visualization of all four cardiac chambers and is particularly useful for assessing ventricular size, valvular function, and pericardial pathology.
Patient and Probe Positioning
Begin by placing the probe at the point of maximal impulse (PMI)—typically located in the left anterior chest, just inferior to the nipple line in most adult males. While the optimal position is the left lateral decubitus position, this view can also be obtained with the patient supine.
Orient the probe with the indicator pointing toward the patient’s left side. Slight lateral angulation of the probe can help align the ultrasound beam along the true long axis of the ventricles, enhancing image quality.
Imaging Objectives
This view captures:
All four cardiac chambers: left and right atria, left and right ventricles
The mitral and tricuspid valves in long axis
The interventricular septum
Anterior and posterior pericardial spaces
Color Doppler can be employed across the mitral and tricuspid valves to assess for regurgitation. Regurgitant flow appears as a “blue back jet” directed opposite to the anticipated direction of flow. The interventricular septum should be evaluated for thickness (generally <2 cm) and motion.
Clinical Utility
Compare right vs. left ventricular size (e.g., for evaluating right heart strain in suspected pulmonary embolism)
Assess for mitral or tricuspid regurgitation
Identify septal wall defects
Detect anterior or posterior regional wall motion abnormalities
Estimate global ventricular function (e.g., via visual estimation or M-mode for ejection fraction)
Technique Tips
Aim the probe face toward the heart
Use slow, small adjustments to improve image quality
Allow anatomic structures to guide probe positioning
Optimize settings (depth, gain) to clearly delineate endocardial borders
Subcostal Four-Chamber View
The subcostal four-chamber view is a valuable window for global cardiac assessment, particularly in critically ill or supine patients. This view allows for evaluation of cardiac contractility, chamber size, and pericardial pathology.
Technique and Probe Positioning
Place the probe just inferior to the xiphoid process, with the indicator oriented toward the patient’s left shoulder. Direct the ultrasound beam cephalad toward the heart. The liver and, to some extent, the right lung serve as acoustic windows to enhance image quality by displacing bowel gas and providing an effective transmission path.
A small-footprint phased array probe is ideal, as it can more easily navigate the narrow subcostal space and intercostal windows. However, smaller probes may reduce image resolution, potentially limiting the ability to visualize adjacent structures.
Imaging Goals
This view captures a long-axis, four-chamber image of the heart, allowing evaluation of:
Ventricular contractility
Valve morphology and regurgitation using color Doppler
Septal integrity
Pericardial space for effusion
An anechoic stripe surrounding the heart may indicate a pericardial effusion; compression of the right atrium or right ventricle in this setting should raise concern for cardiac tamponade. Evaluation of chamber motion is critical in these scenarios.
Clinical Applications
This view is particularly useful in:
Assessing for pericardial effusion or tamponade
Hemodynamic changes following PCI or penetrating chest trauma
Failure to improve after pericardiocentesis
Unexplained hypotension following central venous catheterization
Deterioration after thoracic or cardiac procedures
Also Useful For:
Right vs. left ventricular size comparison (e.g., in PE)
Identifying mitral or tricuspid regurgitation
Detecting septal defects
Evaluating anterior and posterior wall motion abnormalities (similar to the apical four-chamber view)
Sub-costal IVC view:
Inferior Vena Cava (IVC) View – Subcostal Approach
This view is an integral component of focused cardiac ultrasound protocols such as FATE (Focused Assessment with Transthoracic Echocardiography) and RUSH (Rapid Ultrasound for Shock and Hypotension). These frameworks are designed to guide systematic ultrasound evaluation in critically ill patients.
Technique and Probe Positioning
Begin by placing the probe just inferior to the xiphoid process, similar to the subcostal four-chamber view. Orient the probe indicator toward the patient’s head, with a slight rightward angulation to visualize the IVC as it enters the right atrium. By tilting the probe slightly leftward, the descending aorta may also be visualized in long or short axis for assessment of aortic pathology.
Probe Selection
Probes with a smaller footprint are advantageous for navigating the tight subcostal space, particularly when intercostal imaging is necessary. However, image resolution may be reduced. A curved array probe may be used to improve lateral resolution and provide a broader field of view.
Ultrasound Findings
The IVC can be assessed in both long and short axis. The view is facilitated by the acoustic window provided by the liver, but may be limited by bowel gas. The IVC is commonly observed to collapse with respiration—this respiratory variation is clinically valuable. The vessel should be evaluated where it joins the right atrium, near the hepatic vein confluence.
Clinical Relevance
While IVC dynamics are not reliable for predicting fluid responsiveness in all patients, they can be used to estimate central venous pressure (CVP). A simple collapsibility index can be calculated as follows:
Collapsibility Index=IVCmax−IVCminIVCmaxCollapsibility Index=IVCmaxIVCmax−IVCmin
Apply this result to standard reference charts to estimate CVP.
This technique can assist in the evaluation of:
Hypovolemia and volume status
Elevated right atrial pressures
Cardiac tamponade
Aortic abnormalities (with probe tilt)
Reference
Data supported by:
Recommendations for Chamber Quantification: A Report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group. (See pp. 1458–1459)
Parasternal long axis view:
Parasternal short axis view:
The parasternal short axis view provides three key imaging planes—ventricular, mid-papillary, and mitral valve—all obtained with minor probe adjustments in a single intercostal window.
Technique
Begin by positioning the probe in the third or fourth left intercostal space adjacent to the sternum, as for the parasternal long axis view. Then rotate the probe indicator 90 degrees toward the patient’s left shoulder. This orientation provides a short axis view of the heart, primarily focused on the left and right ventricles.
Left Ventricle (LV) should appear circular and thick-walled.
Right Ventricle (RV) should appear crescent-shaped, encircling part of the LV and measuring no more than two-thirds of the LV’s size. RV dilation may suggest pathology such as pulmonary embolism.
1. Ventricular View
This basal view visualizes the LV chamber in short axis and assesses global contraction toward the center. It is ideal for eyeballing ejection fraction and evaluating gross wall motion abnormalities.
2. Mid-Papillary View
By sliding slightly inferiorly, the posteromedial and anterolateral papillary muscles of the mitral valve become visible. The LV should appear as a symmetrical, circular structure. Abnormalities in geometry may suggest structural disease. In hypovolemia, the “kissing papillary muscle sign” (when the papillary muscles nearly touch) indicates low intracavitary volume.
3. Mitral Valve View
Further inferior movement captures the mitral valve in short axis. Though less commonly emphasized in this context, this view can aid in evaluating mitral valve anatomy and function.
Clinical Applications
Assessment of left ventricular function and contractility
Estimation of ejection fraction
Evaluation of RV dilation (e.g., pulmonary embolism)
Identification of pericardial effusion or tamponade
Volume status evaluation (e.g., kissing papillary sign)
Detection of regional wall motion abnormalities
This view is particularly valuable in hemodynamic assessment and critical care echocardiography.
Mitral Level View:
Parasternal Short Axis View – Mitral Valve Level
The mitral valve level of the parasternal short axis (PSAX) view allows for focused assessment of the anterior and posterior mitral valve leaflets. This view is often described as resembling a "fish mouth" opening and closing, due to the dynamic appearance of the valve leaflets in motion.
This view is primarily used to evaluate mitral valve function, particularly in the context of suspected mitral regurgitation identified in the parasternal long axis view. To obtain this image, rotate the probe 90 degrees clockwisefrom the parasternal long axis position. Rotation should be performed slowly and deliberately, with the goal of obtaining a clear short axis image at the level of the mitral valve.
While a live video clip best illustrates the characteristic motion of the mitral valve, still images—such as the one shown here—can demonstrate valve closure and leaflet orientation. The right ventricle is also visible in this view; however, this window is not ideal for detailed assessment of right heart pathology.
Clinical Utility:
Visualization of mitral valve leaflet motion
Assessment of mitral regurgitation in conjunction with long axis view
Evaluation of valve morphology and function