Introduction to Point-of-Care Ultrasound
Using the ultrasound machine
Basic cardiac ultrasound
We will cover two cardiac views:
- Subxiphoid 4-chamber
- Parasternal long axis
We will use these views to assess:
- Cardiac anatomy (chambers, pericardium, valves, etc.)
- Basic contractility (hyperdynamic, normal, depressed, and standstill)
- Pericardial effusion and tamponade
Inferior vena cava ultrasound
The inferior vena cava (IVC) can be used to assess fluid responsiveness in patients with shock or hypotension. The diameter of the IVC should be measured during inspiration and expiration, at a point between the right atrial inlet and where the hepatic veins drain into the IVC. Thus, the spot labelled “IVC” in the image.
A narrow (<2.5cm) IVC with greater than 50% collapse during spontaneous respiration is associated with fluid responsiveness. Fluid responsiveness means an increase in cardiac output after a fluid bolus. A dilated or plethoric IVC (>2.5cm) with less than 50% collapse is associated with minimal fluid responsiveness.
Basic lung ultrasound
Most of lung ultrasound is the study of artifacts.
We will look for pulmonary edema by assessing for:
- A-lines: Bright white (hyperechoic) horizontal lines which are reflections of the pleura
- B-lines: Hyperechoic vertical lines which are reverberation artifacts from edematous interlobular septa
In addition, we will look above the diaphragm to assess for pleural effusion.