Deep Hypothermic Circulatory Arrest

What is deep hypothermic circulatory arrest (DHCA)?

Complete cessation of CPB flow at a core body temperature of less than 18 C

What are cardiac indications of DHCA?

• Aortic surgery

• Pulmonary thromboendarterectomy

• Complex neonatal surgery

What are neurologic indications of DHCA?

• Cerebral aneurysms

• Arteriovenous malformations

What is an indaiction of DHCA?

Renal cell carcinoma with caval invasion

What are the advantages of hypothermia?

1. Reduces metabolic rate and O2 consumption

2. Reduces excitatory neurotransmitter release

3. Slows down enzymatic reactions

4. Decreases inflammatory response

What are disadvantages of hypothermia?

1. Arrythmias

2. Increased plasma viscosity

3. Vasoconstriction

4. Impaired coagulation

5. Metabolic acidosis

6. Hyperglycemia

7. Effects on pharmacodynamics and pharmacokinetics

What are techniques of cerebral perfusion with antegrade?

Side graft attached to right subclavian artery

What are techniques of cerebral perfusion with retrograde?

Cannula in superior vena cava

What are advantages and disadvantages of antegrade and retrograde cerebral perfusion?

What drugs are used for pharmacologic neuroprotection?

• Thiopental

• Propofol

• Steroids

• Mannitol

What is Near Infared Spectroscope (NIRS)?

Technique that provides real time assessment of microcirculatory oxygenation at patients bedside and oxygenated vs deoxygenated Hb has different absorption spectra

What acid base management should be used during cooling before DHCA?

pH stat strategy

What acid base management should be used during rewarming after DHCA?

Alpha stat strategy

How long do most patients tolerate DHCA?

30 minutes