Lesson Outline

Intro

  • Possibly the most universally beneficial POCUS study in the ICU

  • Not limited to patients with heart disease, also beneficial for 

    • Assessing shock states

    • Determining volume status

    • Guiding resuscitation

  • 4 Standard Views

    • Parasternal Long Axis (PLAX)

    • Parasternal Short Axis (PSAX)

    • Apical 4-Chamber (A4C)

    • Subcostal/Subxiphoid View (SC)

  • In later lessons, we’ll delve more into advanced echo including:

    • Objective assessments of left ventricular ejection fraction (LVEF)

    • Estimates of stroke volume and cardiac output

    • Regional Wall Motion Abnormalities (RWMA)

    • Objective assessments of RV function

  • With all echo studies, we’ll be using the phased array probe

Parasternal Long Axis View (PLAX)

  • Obtaining the view

    • Place the probe along the left sternal border at the 3rd or 4th intercostal space

    • Probe marker should be pointed at the patient’s right shoulder

    • May need to move up or down a rib space to obtain a better view

  • Relevant anatomy

    • In this view, the left ventricle (LV) dominates and is located in the center of the screen

    • The interventricular septum (IVS) is located above the LV and the free wall is located below

    • The left atrium and right ventricular outflow tract are also visible in this view

    • The right ventricle (RV) can not be well visualized and the PLAX view is not good for assessing RV function

    • The mitral and aortic valves are both visible, as well as the ascending and descending aorta

  • Subjective Assessment

    • The LV should contract evenly, with its diameter decreasing by about ⅔

      • The walls should not touch (“kissing ventricle”)

      • The anterior leaflet of the mitral valve should touch or come close to touching the IVS

      • If the LV contraction is poor it is termed “hypodynamic”; “hypokinetic” may be applied to the movement of individual walls

      • If the LV is overly collapsable, as in hypovolemia, it is termed “hyperdynamic”

    • Effusions can be seen as anechoic stripes surrounding the heart

      • It can be difficult to distinguish pericardial from pleural effusions as the pericardium and pleura touch

      • Use the descending aorta as a guide; if the fluid is between the aorta and the heart wall, it is pericardial; if the aorta is between the fluid and the heart, it is pleural

Parasternal Short Axis View (PSAX)

  • Obtaining the view

    • From the PLAX, rotate the probe 90 degrees clockwise so that the probe marker is pointed at the patient’s left shoulder

  • Relevant anatomy

    • As in the PLAX, the LV dominates and is in the center of the screen and should appear as a circle

    • The RV is located at the top left corner of the screen with the IVS between them

      • The RV should wrap around the LV, like a croissant sitting next to a cup of coffee

    • The papillary muscles should be visible in the LV at about 4 o’clock and 8 o’clock; these are a good indicator that you are cutting through the middle of the LV

    • Fanning upwards will reveal the mitral valve, this is called the fishmouth view

  • Subjective Assessment

    • Assessment of LV function should always be made at the level of the papillary muscles

      • Too far up and the mitral valve annulus artificially stiffens the LV and will make it appear larger

      • Too far down towards the apex and the LV narrows, making it appear artificially smaller and underfilled

    • The LV should contract symmetrically around a center point

    • The LV should remain circular and the IVS should not flatten or bow into the LV


Apical 4-chamber View (A4C)

  • Obtaining the view

    • Place the probe at the 5th intercostal space along the midclavicular line with the probe marker pointed towards the patient’s left side

  • Relevant anatomy

    • In this view you should see all 4 chambers and both the mitral and tricuspid valves

    • The LV will be in the center of the screen

    • The RV will be to the left of the LV

      • NOTE: this is counterintuitive and can be confusing

    • The left and right atria are located at the bottom of the screen below their respective ventricles

  • Subjective Assessment

    • Similar to the PLAX, LV contraction should be symmetrical with the diameter decreasing by about ⅔

      • The anterior leaflet of the mitral valve should touch or come close to touching the IVS

    • In this view, we can better assess the RV as well

      • It should be about ⅔ the size of the LV with a roughly triangular shape

      • The tricuspid valve should appear to move up and down a significant amount during contraction

      • The IVS should not bow into the LV

    • Signs of RV strain

      • Increased size of the RV

      • Septal bowing to the left

      • Decreased motion of the tricuspid valve

      • McConnell’s Sign: free wall akinesis with apical sparing

    • Pericardial effusion may also be seen in this view

Subcostal/Subxiphoid View (SC)

  • Obtaining the view

    • Place the probe along the patient’s midline just below the xiphoid process with the probe indicator pointing to the patient’s left side

    • Obtaining this view requires you to press in and upwards and flatten the probe against the patient’s abdomen, looking upwards into the rib cage

  • Relevant anatomy

    • This view is essentially the A4C turned on it’s side

    • This view can be confusing because it is essentially “upside down” as the probe is a the top of the screen pointing down, but in reality, we are aiming the probe up from beneath the heart

    • The liver can be seen at the top of the screen

  • Subjective Assessment

    • Similar to the A4C view

  • IVC

    • From the SCV, you can rotate the probe 90 degrees so that the probe marker is pointed at the patient’s head and this will bring the IVC into view

    • You can use this to assess volume status but it should be interpreted with caution, it may be more useful as a trend than as an absolute number