202406162345

Status:

Tags: HBP

Liver

Anatomy

lobes

• classical anatomy
  • divided by falciform ligament
• Sir James Cantlie (1897)
  • divided by middle hepatic vein
    • line between gallbladder fossa to external border of IVC
• Claude Couinaud (1950s)
  • 8 functional segments
    • based on 'segmental pedicle'
      • = blood vessels & bile ducts
• Takasaki classification
  • 4 functional segments

ligaments

• falciform ligament
  • separates Rt & Lt anatomical lobes
• coronary ligaments
  • attach liver to diaphragm

Vascular supply

• dual supply
  • hepatic artery
  • portal vein
• total hepatic supply ~1500ml/min
  • 300ml from HA
  • 1200ml from PV
  • each delivering 50% of O2 to liver

Portal vein

• PV pressure typically 5-10mmHg
  • higher than IVC
• portal hypertension
  • PV pressure >10mmHg
  • PV-IVC gradient >4mmHg

Hepatic vein

• drains into RA
  • ∴ extremely sensitive to venous outflow obstruction / ↑RAP
• prolonged obstruction of outflow → ↑intrahepatic blood volume → hepatic dysfunction

blood reservoir

during acute haemorrhage: ortho-sympathetic mediated vasoconstriction → ↑circulating blood volume by ~25% of blood loss

Zones

Zone 1

• periportal
• surrounding portal space
• most oxygenated
  • ∴ most resistant to haemodynamic insults
• responsible for intense metabolic & synthetic activity
  • e.g. glycogenolysis & gluconeogenesis
• ↑ regenerative capacity

Zone 3

• pericentral
• contiguous w/ central vein
• hypo-oxygenated
  • ∴ susceptible to haemodynamic insults & hypoxia
• ↓ regenerative capacity
• site for ketogenesis
• Phase 1 & 2 metabolism
  • glycuronoconjugation & detoxification

Hepatic resection

References

Major Liver Surgery and the Anesthesiologist Towards a Proactive Strategy