Pulmonary POCUS · Echo Physics Lab
M-mode Guided Lab
Learn M-mode one step at a time with short clinical cases, then explore on your own.
2D · Parasternal long axis
Drag to move the line
Line position
Line position
Line position
Line position
Drag on the 2D image. Keep the line between the ribs.
You can also drag on the 2D image to place the line anywhere.
Pleura
Right atrial pressure
LV long-axis function
RV function
Heart rate 70 bpm
Respiratory rate 14 /min
Heart patterns are in the box below the images.
Sweep speed
Playback
Knowledge check
13 questions on reading M-mode. The simulator stays live so you can check your answer.
M-mode
Hover the M-mode to read depth and structure. Click two points to measure.
Feigenbaum patterns
Pick a pattern to load it and open its description.
Real scans from pulmonarypocus.com
How to read M-mode
- M-mode samples one scan line (the "ice pick") about a thousand times per second. Only structures on that line appear. The vertical axis is depth from the transducer; the horizontal axis is time.
- Heart: at the mitral leaflet tips the anterior leaflet draws an "M" (E point with early filling, A point with atrial contraction) and the posterior leaflet a smaller "W". A large E-point septal separation (EPSS) suggests a dilated LV with reduced ejection fraction.
- Lung: everything above the pleural line is still, so it draws horizontal lines ("waves"). With normal lung sliding, the lung below the pleura moves and draws a grainy "sand" pattern: the seashore sign. With a pneumothorax there is no sliding, so the whole screen is horizontal lines: the barcode or stratosphere sign.
- Ribs block sound. If the line sits on a rib, everything below is an acoustic shadow. Move the line into the intercostal space.
- IVC: measure about 2 cm from the right atrial junction, perpendicular to the IVC. With spontaneous breathing the IVC narrows on inspiration. Collapsibility index = (max diameter - min diameter) / max diameter.
- ASE estimate of RA pressure: IVC 2.1 cm or less that collapses more than 50% with a sniff suggests about 3 mmHg; IVC over 2.1 cm that collapses less than 50% suggests about 15 mmHg; anything in between suggests about 8 mmHg. These rules do not apply during positive pressure ventilation.
Schematic educational model. Dimensions and motion are representative, not patient specific. pulmonarypocus.com