A laryngeal mask airway (LMA) Classic size 4 is inserted in an 65 kg adult patient for an elective laparoscopic cholecystectomy. What is the MOST important reason why a classic LMA is considered unsuitable (and an ETT or ProSeal LMA preferred) for laparoscopic procedures?

• A Classic LMA causes more sore throat than ETT
• B Classic LMA cannot achieve adequate tidal volumes at high airway pressures needed for laparoscopy
• C Classic LMA provides no protection against regurgitation and aspiration when gastric pressures rise with pneumoperitoneum ✓
• D Classic LMA is contraindicated in patients above 50 kg

Explanation

The classic LMA does not protect the airway against aspiration because it rests above the glottis in the oropharynx and does not seal the oesophagus. During laparoscopy, CO2 pneumoperitoneum raises intra-abdominal pressure to 12–15 mmHg, increasing gastric reflux risk. Additionally, high airway pressures needed for ventilation during laparoscopy can exceed the classic LMA seal pressure (~20 cmH2O), causing gas leak and gastric insufflation. The ProSeal LMA has a drain tube for gastric decompression and a higher oropharyngeal seal pressure (~25–30 cmH2O), making it more suitable for laparoscopic procedures.

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

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Written and medically reviewed by the StethoPrep medical team.