During laparoscopic surgery, intraperitoneal insufflation of CO2 causes a series of haemodynamic changes. Identify the correct sequence of events after peritoneal insufflation to 15 mmHg:

• A Increased cardiac output → decreased CVP → increased MAP
• B Decreased SVR → increased heart rate → unchanged ETCO2
• C Initial bradycardia (vagal) → then increased SVR → decreased cardiac output; increased ETCO2 from CO2 absorption ✓
• D Decreased MAP → decreased CVP → increased cardiac output

Explanation

Laparoscopic insufflation to 15 mmHg causes: (1) initial peritoneal stretch triggering a vagal reflex (bradycardia, rarely asystole — requiring deflation and atropine); (2) increased intra-abdominal pressure compresses the IVC, reducing venous return and cardiac output, while simultaneously increasing SVR (via renin-angiotensin, catecholamine release from aortic compression); (3) Trendelenburg position (head-down) partially compensates by improving venous return but increases aspiration risk; (4) CO2 absorption from the peritoneal cavity increases ETCO2 (typically rises 2–5 mmHg), requiring ventilator adjustments. The head-up (Fowler) position worsens venous return further.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.