ObGyn Anesthesia

Maternal Physiologic Changes

• Cardiovascular:
  • 50% increase in plasma volume, 25% increase in RBCs
  • Increases in CO (SV and HR) < decreases SVR = decreased BP (mostly recovers by term).
• Pulmonary:
  • Upper airway edematous and friable
  • Minute ventilation increased (TV > RR) leading to mild respiratory alkalosis
  • FRC (both ERV and RV) decreases and increased O2 consumption means adequate preoxygenation is a must,
• GI
• Nervous
• Renal
• Hepatic