Ultrasound: In Shock and Hypotension

Background

• Several techniques are available for differentiating shock states
• RUSH Protocol was conceived in 2008 and looks are 3 basic aspects of physiology

1. The Pump
   • RV:LV
   • Squeeze
   • Pericardial effusion
2. The Tank
   • IVC
   • Pleural effusions
   • Pulmonary edema
3. The Pipes
   • AAA
   • Aortic dissection
   • DVT

The Protocol

Step 1: The Pump

Step 2: The Tank

Step 3: The Pipes

Rapid Ultrasound for Shock and Hypotension(RUSH) using the HI-MAP approach

• H - Heart (parasternal and four-chamber views)
• I - Inferior Vena Cava (for volume responsiveness)
• M - Morison’s pouch (i.e., FAST exam) and views of thorax (looking for free fluid)
• A - Aortic Aneurysm (ruptured abdominal aneurysm)
• P - Pneumothorax (i.e., Tension pneumothorax)

Heart

Technique: see Cardiac ultrasound

• Pericardial Effusion
  • Parasternal long
  • Change in size <30% between sys and dia = poor LV function
• RV collapse
  • In 4-chamber view, RV should be <60% of LV; if larger think RV failure
• Hyperdynamicity
  • Walls move >90% or touch at end of systole
    • May indicate hypovolemia or sepsis

IVC

Technique: see IVC ultrasound

• Measure 2cm from RA-IVC junction
• If IVC <1.5cm and collapses on inspiration then CVP is low
• If IVC >2.5cm and noncollapsing then CVP is high
  • Suggests fluid unresponsive; patient requires inotropes

Morison's

Technique: see FAST exam

• Assess for free fluid
  • Morison's pouch
  • Splenorenal
  • Bladder

Aorta

Technique: see Aortic ultrasound

• If >5cm assume ruptured AAA until proven otherwise

Pulmonary

Technique: see Ultrasound: Lungs

• Assess for subpleural interstitial edema
  • Look for multiple comet tail artifacts or "B lines"(a few, 3-4, are OK)
    • If multiple found, there is interstitial edema
• Assess for pneumothorax
  • Scan longitudinally in anterior 2nd-3rd IC space, mid-clavicular line
  • Look for lack of sliding or "beach sign"

Other

Classic Ultrasound Findings For Critically Ill Patients

Disease	IVC	Cardiac	Lung (Phased Array)	Lung (Linear)
MI	↑	Focal WMA Mod/Poor squeeze	NL or B-lines	Sliding
Tamponade	↑	RA collapse with filling RV collapse with filling	NL	Sliding
PTX	↑	NL or Hyperdynamic	Lung point Consolidated lung	Absent lung sliding
Sepsis	↓	Hyperdynamic squeeze	NL (see pneumonia)	Sliding
Pneumonia	NL or ↓	Hyperdynamic squeeze	Unilateral B-lines	Sliding
Decompensated HF	↑	Mod/Poor squeeze	Bilateral B-lines	Sliding
PE	↑	RV > LV McConnell's sign	NL or Unilateral B-lines	Sliding

See Also

• Ultrasound (main)
• Undifferentiated shock