Chp. 18: POCUS in Anesthesia Flashcards
What are the four categories of POCUS?
1) Triage: minimum number of views to identify most immediate life-threatening and critical conditions
2) Serial: Monitor progression or resolution of pathology and response to therapy
3) Systemic or Multiorgan: Detect asymptomatic conditions, new developments, and/or to ensure monographically detectable problems have not arisen before undertaking procedures (stable patients)
4) Interventional: Used to reduce complications of procedures
How is ET vs esophageal intubation identified with POCUS?
Only one hyper echoic curved line with distal reverberation artifact is associated with ET intubation. With esophageal intubation, two hyper echoic curved lines with distal reverberation artifact are present.
Is the following endotracheal or esophageal intubation?
Is the following endotracheal or esophageal intubation?
PLUS
Pleural space and lung ultrasound
BAT sign
Aka “gator sign”
Refers to the characteristic appearance of the P-line and adjacent ribs. “Ultrasound beams do not traverse Bone or Air with the probe Transverse to the ribs.”
Normal finding
Name the following POCUS finding
Pleural line
Aka “P-line”
Bright white line below the soft tissue structures of thoracic wall. Lung can be separated from chest wall by space-occupying pathologies (pneumothorax, pleural effusion, d-hernia, pleural masses), in which case the line represents only the parietal pleura.
Glide sign
Result of visceral pleura sliding along the parietal pleura. Presence of a glide sign makes space-occupying pleural space pathology very unlikely.
When is the glide sign difficult to identify?
In patients with rapid/shallow breathing patterns
Lung pulse
Rhythmic movement of the visceral pleura, which is visible at the P-line, when cardiac vibrations transmit through motionless lung. Confirms that parietal and visceral pleura are in apposition to one another.
typically lost when lung sliding is present
A-lines
Hyperechoic horizontal lines that run parallel and equidistant from the skin to the P-line below a soft tissue-to-air interface. Normal in healthy animals.B
B-lines
Aka “comet tails”
Occur when there is decreased aerated lung at the lung periphery. May be normal or representative of alveolar-interstitial pathology.
Defined by five criteria:
1) Vertical white/hyperechoic projections
2) Originating from lung surface
3) Extending through the far field without fading
4) Swinging to-and-fro with lung sliding
5) Often obliterating A-lines if present
When are B-lines significant?
If more than two positive sites on either hemithorax, regardless of number at each site
Abdominal curtain sign (ACS)
Normal sonographic artifact of healthy animals at caudolateral lung margin. Can be used to identify pleural space and lung pathology.
Defined as the sharply demarcated vertical edge artifact that occurs along the caudolateral lung margins where air-filled lung overlies the diaphragm and soft tissues of the abdomen at the costophrenic recess.
Endobronchial intubation is unlikely if what is found on POCUS?
Bilateral lung sliding during respiration
How can PLUS confirm OLV?
Detection of a lung pulse and absence of lung sliding on the non-intubated side of the thorax
How is PLUS used to rule out pneumothorax?
1) Detection of lung sliding and/or lung pulse
2) Detection of B lines and/or lung consolidation arising from P-line
What abnormality of the ACS is identified with pneumothorax?
Asynchronous curtain sign, or the cranial movement of the vertical edge artifact with concomitant caudal movement of abdominal contents during the inspiratory phase of the respiratory cycle
What should be considered if >3 B-lines are visible in a single sonographic window?
Alveolar interstitial syndrome (AIS)
What causes B-lines?
Any process that increases lung density: atelectasis, fibrosis, collagen, neoplastic cells, inflammatory cells, pulmonary edema
What causes lung consolidation?
Atelectasis, hemorrhage, bronchopneumonia, thromboembolism, lung lobe torsion, neoplasia, inflammatory conditions
At what percentage of consolidation is lung consolidation ultrasonographically visible?
90%
Shred sign
Partial lung consolidation. Boundary between consolidated and aerated lung appears shredded (ALI, aspiration pneumonia)
Nodule sign
Partial lung consolidation. Distal border is often well-defined, smooth, and circular (neoplasia, fungal disease)
Hepatization
Translobar lung consolidation
Air bronchograms (POCUS)
Punctate or linear hyper echoic foci visible between the hyper echoic walls of bronchi. Can be dynamic and “shimmer” when air moves within small airways as in pneumonia and inflammatory causes of lung consolidation.
What is the role of APOCUS?
Look for free abdominal fluid, stratify patients at risk for pulmonary aspiration, monitor urinary bladder volume
What is the formula for urinary bladder volume calculation?
L x W x D x 0.52
What is CPOCUS used to evaluate?
Detect low cardiac preload states and assess size of cardiac chambers, thickness of the walls, ventricular function, intracardiac volume status, and presence of pericardial effusion or air emboli
True or False: The absence of B-lines in a patient with respiratory distress essentially rules out cardiac causes.
True
What three right parasternal short-axis views can answer most CPOCUS questions?
Mushroom view, Fish mouth view, LA:Ao
Mushroom view
Estimating volume status and contractility at the left midventricular/papillary muscle region just below the mitral valve
Fish mouth view
Obtained at level of mitral valve, serves as landmark for other views
What is a normal LA:Ao in dogs and cats?
1-1.5
What is the most common right parasternal long-axis view during CPOCUS? What should you see?
Four chamber view. RA and LA should be of similar size, RV internal diameter should be ~1/3 that of the LV internal diameter, the RV free wall should be 1/3-1/2 the thickness of the LV free wall
How does tamponade appear on CPOCUS?
Compression of RA free wall into atrium, intermittently reducing atrial chamber size
What LA:Ao value suggests pseudohypertrophy?
</= 1.1
What does “ventricular chamber obliteration” suggest?
Severe hypovolemia
What should the relative change in size of the LV lumen during diastole and systole be in cats and dogs?
40-60% in cats, 30-50% in dogs
What triad of findings can be indicative of pulmonary hypertension, chronic bronchopulmonary disease, or PTE?
Flattening of the IV septum with an enlarged RV chamber and/or increased RV wall thickness
Caudal vena cava collapsibility index (CVCCI)
CVCCI = CVCdmax - CVCd min / CVCd max
Expresses change (%) in diameter of the CVC during the respiratory cycle. Obtained at subxiphoid view. Assessment of volume status.
Is this patient euvolemic, hypovolemic, or showing signs of increased RA pressures?
Is this patient euvolemic, hypovolemic, or showing signs of increased RA pressures?
Is this patient euvolemic, hypovolemic, or showing signs of increased RA pressures?
What CPOCUS findings should prompt consideration of fluid overload?
History of aggressive fluid therapy combined with: hyperkinetic heart, enlarge LA, distended CVC, and increased B-lines
True or False: A negative POCUS exam excludes pathology.
False.
