Supraglottic Airways: i-gel vs King LT vs LMA in the Field

Supraglottic airways (SGAs) are now the primary rescue airway for most EMS systems — faster to place than an ET tube, with fewer failed attempts and no interruption in compressions.

i-gel

A non-inflatable thermoplastic gel cuff that molds to the periglottic anatomy. No cuff to inflate means one less step and no over-inflation risk. Lubricate the back, front, and sides, insert along the hard palate until resistance, and secure at the teeth. Sizing is by weight: size 3 for 30–60 kg, size 4 for 50–90 kg, size 5 for 90+ kg.

King LT-D

A dual-lumen tube with proximal (oropharyngeal) and distal (esophageal) balloons inflated through a single port. Insert laterally then rotate midline, advance until the connector aligns with the teeth, inflate per size, then withdraw slightly until ventilation is easiest. Size 3 for 4–5 ft tall, size 4 for 5–6 ft, size 5 for over 6 ft — height, not weight.

LMA

An inflatable elliptical cuff that seats in the hypopharynx. Deflate fully, insert along the palate, then inflate the cuff to a minimum sealing volume. Less common in prehospital use but still tested.

Confirmation is identical for all three

• Waveform capnography — the standard of care, not optional.
• Bilateral chest rise and equal breath sounds, absent epigastric sounds.
• No audible leak at normal ventilating pressures.
• Secure the device and recheck after every patient move.

Contraindications

Intact gag reflex, caustic ingestion, upper airway obstruction or burns, and known esophageal disease. Any SGA is a bridge — it does not fully protect against aspiration.

Exam pattern

If the stem gives you a failed intubation attempt, a leaking mask seal, or a cardiac arrest where compressions must continue, the answer is a supraglottic airway — not a third laryngoscopy attempt.