Anaes SAQs · Obstetric anaesthesia
Maternal physiology of pregnancy
Final-examination SAQ for maternal-physiology-pregnancy.
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ANZCAFRCAEDAICABAFCAI
Prompt
Describe the major cardiovascular, respiratory, airway, gastrointestinal, haematological and pharmacological changes of term pregnancy and how each alters your conduct of general and neuraxial anaesthesia for caesarean section.
Model answer
CVS. ↑CO (up to ~50%), ↑blood volume, ↓SVR; aortocaval compression → left tilt or manual uterine displacement.[1][4]
Resp. ↑MV, ↓FRC ~20%, ↑VO2 substantially → rapid desaturation; meticulous preoxygenation with nasal oxygenation and mask ventilation.[1][5]
Airway/GI. Oedema/friability; aspiration risk → RSI, OAA/DAS plan.[1]
Haem. Physiological anaemia; hypercoagulable VTE risk; PPH readiness; TXA if PPH.[3]
Pharm. MAC reduced; LA dose needs reduced; phenylephrine infusion for spinal hypotension.[2][5]
References5ShowHide
- [1]Mushambi MC et al. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics. Anaesthesia, 2015.PMID 26449292
- [2]Ngan Kee WD et al. Prophylactic phenylephrine infusion for preventing hypotension during spinal anesthesia for cesarean delivery. Anesth Analg, 2004.PMID 14980943
- [3]WOMAN Trial Collaborators. Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial. Lancet, 2017.PMID 28456509
- [4]Koziol KJ, Isath A, Aronow WS, et al. Cyanotic Congenital Heart Disease in Pregnancy: A Review of Pathophysiology and Management. Cardiol Rev, 2024.PMID 36716356
- [5]Delgado C, Ring L, Mushambi MC General anaesthesia in obstetrics. BJA Educ, 2020.PMID 33456951