CASA

The Primary Indication is in Cardiac Arrest. Performance of US must not interfere with CPR.

During CPR

  • Assess cardiac activity
  • Assess pericardial effusion/tamponade
  • Assess right heart strain (possible PE)
  • Rule out large pneumothorax
  • Assess for intra-abdominal hemorrhage (FAST)
  • Read/evaluate saved clip

During pulse check

  • Assess cardiac activity
  • Record 10 second clip

Diagnosis

In non-shockable rhythms, POCUS can identify reversible causes of CA, such as tamponade, pulmonaryembolism, hypovolemia and tension pneumothorax.

Prognosis

  • Differentiate a true asystole (cardiac standstill) versus a still-contracting heart.
  • Patients with cardiac contracility have a higher chance of achieving ROSC.

Probe

Phased Array in cardiac presets/exam type

CASA Windows (Figure 1)

Subxiphoid

  • Rapidly assess for cardiac activity (Clip 1)
  • Assess for pericardial fluid/tamponade (Figure 2)
  • Assess RV function/size
  • If unable to obtain, parasternal long axis (PLA)

Lung (Clip 2)

  • Assess lung sliding right and left of the sternum

FAST

  • Assess for free fluid (possible hemorrhage)

Tips

POCUS must not interfere with the CPR

ROSC should be determined based on the presence of a pulse, capnography and arterial pressure readings

Figures and Clips

Figure 1 - Probe Placement

Figure 2 - (A) Normal Pericardium (B) Cardiac Tamponade

Figure 3 - Abdominal Hemorrhage

Clip 1 - Subxiphoid Window

Clip 2 - Lack of Lung Sliding

References

Gardner, Kevin F., et al. “The Cardiac Arrest Sonographic Assessment (CASA) exam–A standardized approach to the use of ultrasound in PEA.” The American journal of emergency medicine 36.4 (2018): 729-731.

Blanco, Pablo, and Carmen Martínez Buendía. “Point-of-care ultrasound in cardiopulmonary resuscitation: a concise review.” Journal of ultrasound 20.3 (2017): 193-198.