Anaesthesiology - Critical Care Medicine - POCUS Flashcards
Define different echogenicities produced by US probe
- Isoechoic
- Hyperechoic – e.g. stones
- Hypoechoic – e.g. lymph node
- Anechoic – e.g. fluid
Define colours on colour flow doppler
Blue away, Red towards (BART)
4 positions of cardiac imaging by POCUS
Define the structures seen on PLA on cardiac POCUS
S
Define the structures seen on PSA on cardiac POCUS
Define the structures seen on apical 4 chambers view on cardiac POCUSS
Define the structures seen on subxiphoid view on cardiac POCUS
Define Cavel Index and clinical use
Cavel index measures respiratory variation in diameter of the inferior vena cava to predict fluid responsiveness in spontaneous breathing emergency department patients with signs of shock.
Index correlates IVC size on POCUS with CVP
Assesses volume status and guides fluid management: low caval index in a patient with signs of shock is associated with fluid unresponsiveness; high caval index is inconclusive
What is the normal size of the right ventricle at the apical 4 chamber view?
right ventricle is less than 2/3 of the size of the left ventricle
Where is pericardial effusion in relation to the descending aorta in the parasternal long axis?
Anterior to the descending aorta
List applications of cardiac POCUS
Assess cardiac function
Valvular assessment: Valve morphology (number of leaflets, movement, rheumatic heart valves, calcifications, vegetation)
Fluid status
Pericardial effusion +/- tamponade
Acute right heart strain (e.g. acute pulmonary embolism)
Aortic dissection
Methods to assess left heart function on POCUS
LeLt ventricular ejection fraction
- Assess in Parasternal long axis view
- estimate bu “eyeballing LV movement” or degree of “LV squeeze”
- Measure distance of anterior mitral valve leaflet to septum (MV slapping septum = >50% LVEF; MV not touching septum = 30-50%; MV not moving = <30% LVEF)
Assess severity of mitral regurgitation on POCUS
Observe doppler colour and size of mitral regurgitation jet:
Jet <20% of LA area = mild MR
Jet 20-40% of LA area = moderate MR
Jet >40% = severe MR
Identify pathology
Calcified aortic valve (bright area), with severely impaired valve opening
Identify pathology
Aortic regurgitation
Jet return to LA during systole
Identify pathology
Tricuspid regurgitation
Features of Rheumatic heart disease on cardiac POCUS
- Mixture of valvular dysfunction
- Atrial fibrillation
- Systolic doming on anterior mitral valve leaflet with “Hockey stick” appearance
- LA dilation
Identify pathology
Mitral valve calcification
Identify pathology
Endocarditis with vegetation on MV
Define position of pericardial effusion and pleural effusion to the descending aorta
Pericardial effusion: Anterior to descending aorta
Pleural effusion:
Posterior to descending aorta
Cardiac tamponade
Features on cardiac POCUS
Early: Systolic collapse of RA
Late: Diastolic collapse of RV
Identify pathology
Massive pericardial effusion
Features of pulmomary embolism on cardiac POCUS
Acute right heart strain:
RV dilatation
Interventricular septum bowing during systole into LV - D-shape LV
Aortic dissection
Features on cardiac POCUS
Dilated aortic root
Dissection flap visible
Aortic regurgitation
Lung POCUS
- Standard views
- Positions
R1/L1: Anterior Superior lung field for pneumothroax and/or interstitial edema
- Straight linear probe
- At 2nd and 3rd ICS at MCL at left and right side
- Find Batwing Sign (confirm between two ribs) and Lung Sliding (visceral and parietal pleura sliding over) and A-lines (equdistant artifacts under pleural line)
R2/L2: Lateral lung view
- Midaxillary line at 6th-7th ICS, lateral to nipple
R3/L3: Posterolateral/ Posterior- Inferior lung view
- Posterior axillary line, 10th-12th ICS
- Indicator towards patient’s head
- Find Liver (R) or spleen (L), kidney, diaphragm, spine
- FInd curtain sign (aerated lung slide over organs during inspiration)
Absent lung sliding on lung POCUS
Specific signs
Ddx
There is no lung sliding present when the parietal and visceral pleura become separated by air (pneumothorax) or fluid (pleural effusion).
Furthermore, severe COPD or anything that hyperinflates the lungs can markedly reduce pleural sliding.
Ddx:
- Pneumothroax
- Pleural effusion
- Pleurodesis
- Acute infectious/ inflammatory consolidation
- Fibrotic lung diseases
- ARDS
- Mainstem intubation
Absence of lung sliding can be seen using B-mode or using M-mode (stratosphere sign and barcode sign).
Interstital edema
Features on Lung POCUS
B-lines form when interlobular septa and lung tissue thicken or fill with fluid.
- Appear ray-like, hyperechoic, and vertical (c.f. A lines that are horizontal)
- Emanate from the pleural line.
- Move with lung sliding.
- Extend to the periphery of the far-field.
- Can be associated with a thickened pleural membrane.
Fluid build-up causes convergence of B-lines into “Confluent B-lines.”
Lung consolidation
Features on POCUS
Consolidation is fluid build-up in lungs
ultrasound findings will progress from multiple B-lines, confluent B-lines, subpleural consolidation, the shred sign, to a dense consolidation, and then “hepatization of the lung”
Air-trapped inside consolidations cause:
- Dynamic Air Bronchograms tend to occur in pneumonia and move as the patient inhales and exhales.
- Static Air Bronchograms tend to occur when air bubbles are trapped behind an obstruction, as occurs in atelectasis, and don’t move with respiration.
Pleural effusion
Features on POCUS
Signs: The PLAPS point is the most specific and sensitive view used to diagnose pleural effusion.
- Spine Sign: sound waves can pass through the pleural fluid allowing the spine to be seen above the diaphragm.
- Jellyfish sign: consolidated lung is seen floating in the pleural effusion
- Sinusoid Sign: parietal and visceral pleura moving closer and further apart while the patient breathes
- Quad Sign: anechoic appearance often delineated by the pleural line, the rib shadows, and the lung line
- Plankton Sign: shows an exudative effusion with swirling, hyperechoic debris.
- Hematocrit Sign: echogenic layering of material in a pleural effusion
- Loculated Pleural Effusions
COPD or Asthma
Features on POCUS
normal findings such as lung sliding and A-lines but the patient still has symptoms and difficulty breathing, you should consider COPD, asthma, pulmonary embolism, or nonpulmonary conditions causing the patient’s dyspnea.
– Bilateral A-lines
– Reduced lung sliding
Pulmonary embolism
Features on POCUS
– Bilateral A-Lines
– Deep Vein Thrombosis in Upper or Lower Extremities
– Right Ventricular Enlargement (massive/submassive PE)
Outline diagnosis of pneumothroax by POCUS
First, if lung sliding is present, you can rule out pneumothorax with 100% accuracy at that ultrasound point
Second, if lung sliding is ABSENT, you should not automatically assume pneumothorax. Think ddx: severe consolidation, chemical pleurodesis, acute infectious or inflammatory states, fibrotic lung diseases, acute respiratory distress syndrome, or mainstem intubation.
Third, if a lung point is present, you can rule in pneumothorax with 100% accuracy. Lung point is when you can see the transition between normal lung sliding and the absence of lung sliding. This is the transition point between the collapsed lung and normal lung.
