EDAIC Point-of-Care Ultrasound and Perioperative Echocardiography — Questions and Answers
Question 1: On lung ultrasound, B-lines are defined as hyperechoic, laser-like vertical artefacts arising from the pleural line. Which finding is most consistent with acute cardiogenic pulmonary oedema?
- Absent B-lines bilaterally
- Unilateral B-lines in an upper zone only
- Three or more B-lines per intercostal space in bilateral dependent zones (Correct answer)
- A single B-line in one zone
Correct answer: Three or more B-lines per intercostal space in bilateral dependent zones
Three or more B-lines per intercostal space (a 'B-pattern') in bilateral dependent lung zones constitutes a 'positive' lung ultrasound for pulmonary interstitial syndrome, consistent with cardiogenic oedema or diffuse pneumonitis. Unilateral B-lines suggest focal pathology (pneumonia, contusion). Absent B-lines indicate normal aeration or pneumothorax (where lung sliding is also absent).
Question 2: Which lung ultrasound finding confirms the presence of a pneumothorax in a trauma patient?
- Bilateral B-lines
- Absent lung sliding with A-lines and a 'lung point' (Correct answer)
- A pleural effusion anechoic stripe
- Comet-tail artefacts from the pleura
Correct answer: Absent lung sliding with A-lines and a 'lung point'
Pneumothorax is diagnosed on lung ultrasound by: (1) absence of lung sliding, (2) absence of B-lines (replaced by A-lines), and (3) the presence of a 'lung point' — the transition between sliding and non-sliding pleura — which is pathognomonic for pneumothorax. Absent sliding alone can also occur with apnoea or main-stem intubation, so the lung point is the most specific sign.
Question 3: In a focused cardiac ultrasound (FoCUS) parasternal long-axis (PLAX) view, which structure is NOT routinely visualised?
- Left ventricular outflow tract (LVOT)
- Mitral valve leaflets
- Aortic valve and aortic root
- Right ventricular outflow tract and pulmonary valve (Correct answer)
Correct answer: Right ventricular outflow tract and pulmonary valve
The PLAX view images the left atrium, mitral valve, left ventricle, LVOT, aortic valve, aortic root, and the descending thoracic aorta in cross-section. The right ventricular outflow tract and pulmonary valve are best seen in the parasternal short-axis (PSAX) view at the aortic level or in the right ventricular inflow-outflow view.
Question 4: In a spontaneously breathing patient in shock, inferior vena cava (IVC) diameter is 10 mm and collapses > 50% with inspiration on subcostal ultrasound view. What is the most appropriate interpretation?
- Fluid overload; diuresis is indicated
- Low right atrial pressure, suggesting likely fluid responsiveness (Correct answer)
- Cardiac tamponade; pericardiocentesis is needed
- Pulmonary hypertension
Correct answer: Low right atrial pressure, suggesting likely fluid responsiveness
In a spontaneously breathing patient, an IVC diameter < 21 mm with > 50% inspiratory collapse correlates with low right atrial pressure (≤ 5 mmHg) and suggests the patient is likely to respond to fluid administration. This finding should be integrated with other clinical parameters; IVC assessment is less reliable in ventilated patients (where expiratory distensibility index is used instead).
Question 5: Transthoracic echocardiography reveals a large circumferential pericardial effusion with right ventricular diastolic collapse. What does right ventricular diastolic collapse indicate?
- Normal physiological variant
- Cardiac tamponade physiology with haemodynamic compromise (Correct answer)
- Right ventricular infarction
- Pulmonary embolism causing RV dilation
Correct answer: Cardiac tamponade physiology with haemodynamic compromise
Right ventricular free wall collapse during diastole (when intracardiac pressure should be lowest) indicates that intrapericardial pressure exceeds right ventricular diastolic pressure, a hallmark of cardiac tamponade. This echocardiographic sign precedes haemodynamic collapse and mandates urgent pericardiocentesis or surgical drainage. RV infarction causes dilation, not diastolic collapse.
Question 6: When using the FAST (Focused Assessment with Sonography in Trauma) protocol, which view is used to detect free fluid in Morrison's pouch (the hepatorenal recess)?
- Subxiphoid (subcostal cardiac) view
- Left upper quadrant (splenorenal) view
- Right upper quadrant view (Correct answer)
- Suprapubic (pelvic) view
Correct answer: Right upper quadrant view
Morrison's pouch is the potential space between the liver and the right kidney — the right upper quadrant FAST view. It is the most dependent recess in the peritoneal cavity when supine and is therefore the first and most sensitive site to detect haemoperitoneum. The left upper quadrant view assesses the splenorenal space, the subxiphoid view the pericardium, and the suprapubic view the pelvis.
EDAIC Point-of-Care Ultrasound and Perioperative Echocardiography
On lung ultrasound, B-lines are defined as hyperechoic, laser-like vertical artefacts arising from the pleural line.
Which finding is most consistent with acute cardiogenic pulmonary oedema?