LMA Seal Pressure — FRCA Primary MCQ
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Correct answer: E — 20 cmH2O
The correct answer is E. A correctly positioned first-generation cuffed LMA typically has an oropharyngeal leak pressure of approximately 15–20 cmH2O; measured values vary with device size, cuff pressure, insertion quality and head position. The leak pressure is the circuit pressure at which gas begins to escape around the airway and therefore indicates the effective seal for positive-pressure ventilation. Second-generation devices, particularly the ProSeal LMA, generally provide higher pressures, commonly around 25–30 cmH2O. A pressure of 60 cmH2O is a recommended upper limit for intracuff pressure in many cuffed supraglottic devices, not the airway seal pressure. Values of 5 or 10 cmH2O indicate a poor seal, whereas 40 cmH2O is not typical of a first-generation LMA.
Reference: Brandhorst P et al. Comparison of the oropharyngeal leak pressure in head rotation between a first-generation laryngeal mask and the i-gel laryngeal mask during general anesthesia—a randomized controlled trial. BMC Anesthesiology. 2025. https://pubmed.ncbi.nlm.nih.gov/40963146/