Emergency medicine ultrasound Guide

Basics & Set Up

PROBES

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GAIN

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M MOde

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Doppler

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KNOBOLOGY

Master of Curly Hair

ARTIFACTS

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POCUS

CARDIAC

• Technique
• Normal Anatomy
• Pathology
• Pitfalls

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Tamponade

​EFAST

• Technique
• Anatomy
• Pathology
• Pitfalls

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PROBE: Phased Array or Curvilinear
MODE: FAST
STARTING DEPTH: 8 cm

SCANNING:

1. Use either the phased array or curvilinear probe to evaluate Morrison's pouch (space between the liver and kidney).  Be sure to examine the caudal tip of the liver and inferior pole of the kidney, as this is the area where fluid often accumulates first.
2. Scan through the retrovesicular space (space between rectum and bladder) in transverse and sagittal planes.
3. Examine the perisplenic space (between the spleen and the diaphragm).  This view is often slightly more posterior than Morrison's pouch.
4. Place the probe in the subxiphoid space to obtain a subcostal view of the heart and examine for pericardial effusion.
5. Place the curvilinear (or switch to the linear probe) to evaluate the lungs for sliding by looking in the second intercostal space bilaterally.

VIEWS:
☐ Morisson's Pouch
☐ Retrovesicular space
      ☐ Sagittal
      ☐ Transverse
☐ Parasplenic
☐ Subcostal Cardiac
☐ Lung sliding

Morrison's Pouch, interface between liver and kidney

Retrovesicular sagittal view

Subcostal view

Parasplenic view, located between spleen and diaphragm

Retrovesicular transverse view

Lung Sliding 

Morrison's Pouch, ​free fluid

Retrovesicular view sagittal, ​free fluid

Pericardial Effusion

Parasplenic view, free fluid 

Retrovesicular view transverse, free fluid

• Incomplete view of Morrison's pouch
  • Scan all the wall to the caudal tip of the liver/inferior pole of the kidney
• Missed free fluid posterior to the bladder
  
  • Due to posterior acoustic enhancement, fluid behind the bladder may appear isoechoic.  Adjust the TGC to remedy this artifact.
• ​Difficulty obtaining parasplenic view​
  • Adjust probe to get a more posterior view of the LUQ

OB

• Technique
•  Anatomy
• Pathology
• Pitfalls

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PROBE: 
 <6 weeks = Enodcavitary
 >6 weeks = Curvilinear 
MODE: EARLY OB                           
STARTING DEPTH: 16 cm

SCANNING :

1. Scan and obtain clips through the entire uterus in transverse and sagittal planes
   
2. Identify IUP, measure FHR, and gestational age
3. Look for the presence of free fluid
   
4. Scan through the adnexa
   

VIEWS:
☐ Uterus in transverse and sagittal planes
☐  IUP within uterus
     -     GS + yolk sac OR fetal pole in the fundus
​☐ Adnexa
☐​ Cul-de-sac​

MEASUREMENTS:
☐  Fetal HR (M-Mode)
☐ Gestational age (choose one method)​​
     -     Gestational sac 
     -     CRL (head to bottom)   
     -     BPD (outer to inner, perpendicular to falx)
     -     Femur length
☐ Fetal demise
     -     fetal pole > 7mm without HR, OR
     -     GS >25 mm without fetal pole

Sagittal uterus with endocavitary probe

Transverse uterus with endocavitary probe

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Sagittal uterus with transabdominal probe

Transverse uterus with transabdominal probe

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Transverse view of the adnexa

IUP,  yolk sac within gestational sac in fundus

Ruptured ectopic pregnancy 

Intrauterine demise, no fetal pole seen in GS

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Subchorionic hemorrhage

Molar pregnancy

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Free fluid in the cul-de-sac

Ovarian Cyst

Pitfall           ​	Solution
Not able to identify the gestational sac with curvilinear probe           ​	Switch to the endocavitary probe
Difficulty identifying ovaries  ​	Look lateral to the uterus; ovaries typically have a "chocolate chip appearance"
Mistaking ectopic for IUP  ​	IUP = fetal pole/yolk sac within GS in fundus
Missing a heterotopic pregnancy      ​	Even if an IUP is identified, be sure to examine the adnexa
Failing to perform a bedside US because bHCG is below the "discriminatory zone"	A beside US should be performed if indicated, regardless of the quantitative bHCG

LuNG

• Technique
• Anatomy
• Pathology
• Pitfalls

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PROBE: Linear or Curvilinear
MODE: Thoracic/Lung
STARTING DEPTH: 6 cm  ​

SCANNING:

1. Place the probe with the marker facing towards patient's head on anterior chest wall (2nd-3rd intercostal space) and evaluate for lung sliding 
2. Look for B-lines, consolidation, pleural effusion
3. If looking for edema or pneumonia, move probe to evaluate midaxillary line and costophrenic angle bilaterally 

​VIEWS (right and left):
☐ Lung sliding 
☐ Anterior chest
☐ Mid-Axillary line
☐ Costophrenic angle

Normal Lung Anatomy

Video clip of normal Lung Sliding 

B-Lines

Consolidation

Pleural Effusion

Video clip of pneumothorax with lung point

• Absence of lung sliding mistaken for pneumothorax
  • ​Absent lung sliding can also be seen in: right maintem intubated patients, patients with bullous disease, severe consolidation
• Missed pneumothorax 
  • Pneumothorax will only be seen in the scanned area.  Likelihood of identifying pneumothorax is highest when the anterior and apical areas of the chest are scanned.  
• Mirror artifact mistaken for lung consolidation
  
  • A mirror artifact duplicate an image by reflection.  Confirm that that what appears to be a consolidation is not actually a reflection of the liver or spleen.
• Intra-abdominal fluid mistaken for pleural fluid
  • ​Identify the location of fluid in relation to the diaphragm (above or below) to correctly identify intrabdominal vs intrathoracic fluid.
    

​RENAL

• Technique
• Anatomy
• Pathology
• Pitfalls

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​SOFT TISSUE

• Technique
• Anatomy
• Pathology
• Pitfalls

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​​Biliary

• Technique
• Anatomy
• Pathology
• Pitfalls

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DVT

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THORACIC

AORTA

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Pediatric POCUS

Appendix

• Technique
• Anatomy
• Pathology
• Pitfalls

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PROBE: Linear or Curvilinear
MODE: Abdomen or Peds Abdomen          STARTING DEPTH: 4 cm      

SCANNING:

1. Use Graded compression to compress gas
2. Scan right abdomen from pelvis to liver edge
3. Trace cecum to appendix 
4. Visualize appendix in short and long axis 

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VIEWS     
☐Psoas Muscle
☐Iliac Vessels
   Appendix 
      ☐Long axis with blind sac connected to cec
​      ☐Short axis with target sign

Measurements:
Diameter < 6mm
Wall thickness < 3mm

Appendix in long axis

Appendix in short axis

Appendix in long axis

The appendix is a blind-ended tubular structure located in the RLQ.  A normal appendix is concentrically layered, mobile, and compressible.  Location of the tip of the appendix is variable, the most common being pelvic and retrocecal.

Appendicitis 

 Diagnostic Criteria
Diameter > 6 mm or
Wall thickness > 3mm
+
Signs of inflammation
Non-compressible
​Aperistaltic
Fat stranding
​Fecalith
​Free Fluid

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Pitfalls of Appendix US​

• Appendix obscured by bowel gas 
  • ​Move bowel gas using graded compression
• Thickened ileum is mistaken for appendix​​
  • ​Identify blind ended pouch and trace to cecum
• Distal tip appendicitis is overlooked
  • ​Visualize entire length of appendix
• False Positive interpretation
  • ​A normal appendix can be > 6mm
  • For positive finding, there must be an enlarged appendix + signs of inflammation
• False Negative interpretation
  • ​A normal appendix must be visualized for a negative study

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Pylorus

• Technique
• Anatomy
• Pathology
• Pitfalls

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PROBE: LINEAR
MODE: PEDS ABDOMEN                
DEPTH: 4 cm

SCAN:
1. Place patient in comfortable position 
3. Place probe in the epigastrium with marker facing patient's right
4. Use the liver and gallbladder as an acoustic window to visualize the pylorus in its long axis
5. Turn the probe marker towards the patient's head to visualize the pylorus in short axis

VIEWS:
☐ Pylorus in  short axis
☐ Pylorus in long axis

 MEASUREMENTS:
☐ Channel length < 15mmm
☐ Muscle wall < 3mm

Pylorus short axis

Pylorus Transverse 

Pyloric Stenosis in Long Axis

Pyloric Stenosis in Short Axis

• Unable to identify pylorus
  • Increase depth to identify landmarks (liver, gallbladder, stomach).  Once stomach is identified, decrease depth, and follow stomach antrum to pylorus
• ​Measurements are incorrect
  • Measure only the hypoechoic muscle layer on one side of the channel
• Pylorospasm
  • Transient muscle spasm that can appear like pyloric stenosis.  Resolves with feeding. ​

Intussusception

• Technique
•  Anatomy
• Pathology
• Pitfalls

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PROBE: LINEAR
MODE: PEDS ABDOMEN                
DEPTH: 6 cm

SCAN:
1. Place patient in comfortable position and use warm gel to help patient tolerate US
2. Start with the probe marker to the patient's right in the RLQ and scan up to the RUQ.
3. Turn the probe with the marker to the patient's head and scan across the transverse colon.
4. Turn the probe marker back to the patient's right and scan down from LUQ to the LLQ.

VIEWS:
☐ Short axis with target sign
☐ Long axis

 MEASUREMENTS:
☐ Short axis target > 2 cm is positive for intussusception 

RLQ normal anatomy, start scan by identifying these landmarks

Colon, scalloped, dirty shadowing, poor penetrance
Small bowel, multiple loops seen with peristalsis

Ileo-colic Intussusception in short axis with target sign

Ileo-Ilial intussusception, distinguished by size < 2cm and presence of peristalsis

Ileo-colic Intussusception in long axis with "sandwich sign" 

• Intussusception mistaken for a lymph node or kidney.  
  • Intussusception can be distinguished from lymph node by size and presence of concentric circles (loops of bowel).
  • Intussusception can have the appearance of the kidney in long axis.  Identify the kidneys separately to distinguish from intussusception.

CRANIAL 

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