When placing a supraglottic airway, is a rapid‑acting paralytic still required in addition to sedation?

Supraglottic Airways and Muscle Relaxants

Routine use of a muscle relaxant (paralytic) is probably not required for supraglottic airway insertion, as success rates are commonly high with adequate sedation alone. 1

Key Distinction from Endotracheal Intubation

The approach to supraglottic airways differs fundamentally from endotracheal intubation:

• For endotracheal intubation: Muscle relaxants are strongly recommended to reduce pharyngeal/laryngeal injury (from 18.7-22.6% down to 9.7%) and facilitate successful placement 1
• For supraglottic airways: Routine paralysis is probably not recommended (GRADE 2 recommendation with strong agreement) 1

When Adequate Sedation is Provided

Without muscle relaxants, laryngeal mask insertion success rates are commonly high and ventilation conditions are often satisfactory when appropriate sedation is used. 1

The critical factor is the depth of sedation:

• Propofol-based protocols: Typically provide excellent conditions without paralytics 1
• Low-dose hypnotic/opioid protocols: May benefit from neuromuscular blockade 1
• Non-propofol induction agents: Have higher rates of adverse insertion events that decrease with neuromuscular blockade 1

When Muscle Relaxants ARE Recommended

Administration of a muscle relaxant is probably recommended (GRADE 2+) in case of airway obstruction related to a supraglottic device. 1

Specific scenarios include:

• Glottic closure or laryngospasm after supraglottic airway placement 1
• Failed ventilation through the supraglottic device despite adequate positioning 1
• Incomplete airway obstruction that is easily reversible with muscle relaxation 1

Practical Algorithm

1. Initial placement: Use adequate sedation (preferably propofol-based) without routine paralysis 1

2. If insertion difficulty occurs: Consider adding muscle relaxant if sedation depth is inadequate 1

3. If airway obstruction develops after placement: Administer muscle relaxant (succinylcholine 1.0 mg/kg IV or rocuronium/atracurium 0.1-0.2 mg/kg) 1

4. Emergency situations: In cardiac arrest, supraglottic airways can be inserted without interrupting chest compressions and do not require paralysis 1, 2

Important Caveats

• Supraglottic airways do not require laryngoscopy, eliminating the primary reason for paralysis (improved visualization and reduced trauma) 1
• The overall evidence quality remains low due to heterogeneity in anesthesia protocols and outcomes 1
• Second-generation supraglottic devices with esophageal drains may reduce aspiration risk and are preferred when available 1
• Continuous waveform capnography should be used to confirm effective ventilation through the supraglottic airway, though its utility depends on device design 1, 2