Common Mistakes & Exam Pearls
The abrupt fall in SVR & preload with reflex tachycardia is poorly tolerated. Use a slow, titrated epidural (or GA in NYHA III–IV).
Tachycardia shortens diastole and drops LV filling across the fixed valve. Treat pain, light anaesthesia and AF; keep the patient slow and in sinus rhythm.
Bolus oxytocin drops SVR with reflex tachycardia; ergometrine raises PVR and BP. Use a dilute oxytocin infusion; avoid ergometrine (and caution with carboprost in PAH).
Supine hypotension reduces preload and uteroplacental perfusion — always use left-lateral tilt / a wedge.
The post-partum autotransfusion makes the first 24–48 h the highest-risk window for pulmonary oedema — monitor in HDU/ICU.
Q: State the haemodynamic goals in MS.
Maintain preload & SVR, avoid tachycardia (and bradycardia), maintain sinus rhythm, avoid rises in PVR (hypoxia/hypercarbia/acidosis), and avoid aortocaval compression.
Q: How does pregnancy worsen MS?
↑ Blood volume 30–50%, ↓ SVR with ↑ HR (progesterone) shortening diastole, NYHA worsens by a grade, and the delivery/post-partum autotransfusion precipitates pulmonary oedema.
Q: Grade severe mitral stenosis.
Valve area <1.0 cm², mean gradient >10 mmHg, PAP >50 mmHg, NYHA III–IV.
Q: Regional technique of choice for LSCS in MS?
A slowly-titrated graded epidural (avoid single-shot spinal); GA for NYHA III–IV with the pressor response attenuated.
Q: How do you give oxytocin, and which uterotonics are avoided?
Dilute infusion ~10–20 U in 1 L at 40–80 mU/min (never bolus); avoid methylergometrine (↑ PVR/BP) and use carboprost cautiously in PAH.
Q: What does the S₂–opening snap interval tell you?
A shorter interval indicates more severe stenosis (higher LA pressure opens the valve sooner).
Q: What is Ortner's syndrome?
Hoarseness from compression of the left recurrent laryngeal nerve by an enlarged left atrium / pulmonary artery.
References
- Dr. Tanya Chawla. MS with PAH for LSCS — viva notes (DrNB June 2019 Paper 3; primary source for this topic).
- Hines RL, Marschall KE (eds). Stoelting's Anesthesia and Co-Existing Disease, 8th Edition. Valvular Heart Disease. Elsevier; 2022.
- Chestnut DH, et al. (eds). Chestnut's Obstetric Anesthesia: Principles and Practice, 6th Edition. Cardiac Disease in Pregnancy. Elsevier; 2019.
- Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail's Clinical Anesthesiology, 7th Edition. Anaesthesia for Patients with Valvular Heart Disease & Obstetric Anaesthesia. McGraw-Hill; 2022.