Anaes SAQs · Applied cardiovascular & respiratory physiology
Maternal physiology
Primary — cardiovascular (volume 40 percent, CO 30 to 50 percent, SVR falls); respiratory (minute ventilation rises, FRC falls 20 percent, rapid desaturation); GI (LES tone falls, aspiration risk, RSI from 16 to 20 weeks); aortocaval compression (from 20 weeks, left tilt); MAC falls 30 percent; PK changes (Vd, protein binding, clearance); haematological (haemodilution, hypercoagulable); spinal hypotension.
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Prompt
Describe the physiological changes of pregnancy relevant to the anaesthetist, including cardiovascular, respiratory, gastrointestinal and pharmacokinetic changes. Explain the significance of aortocaval compression and the reduced MAC.
Question
Describe the physiological changes of pregnancy relevant to the anaesthetist, including cardiovascular, respiratory, gastrointestinal and pharmacokinetic changes. Explain the significance of aortocaval compression and the reduced MAC.[5]
[5]References5ShowHide
- [1]Astete M, et al. Perioperative cardiac arrest in obstetric patients. Rev Esp Anestesiol Reanim, 2026.PMID 41850587
- [2]Yu XQ, et al. The Median Effective Dose of Phenylephrine Infusion for Prevention of Spinal-Induced Hypotension During Cesarean Delivery in the 15° Left-Tilt vs. Supine Positions: A Randomised Control Study. Drug Des Devel Ther, 2026.PMID 42137121
- [5]Keresztes M, et al. Target-Controlled Infusion for Caesarean Delivery Under General Anesthesia: From Conventional Pharmacokinetic Models to Physiologically Based Pharmacokinetic Modeling. Life, 2026.PMID 42195295
- [4]Kim JN, et al. Effectiveness of lumbar wedge in preventing intraoperative hypotension during cesarean delivery in multiple gestation: a retrospective analysis. BMC Pregnancy Childbirth, 2025.PMID 41350653
- [3]Shatalin D, Binyamin Y, Weinstein J, et al. General anesthesia for cesarean delivery: Israeli national survey. J Anesth Analg Crit Care, 2025.PMID 40598688