How can a flexible laryngeal mask airway (LMA) ProSeal be safely used in an adult patient positioned prone?

Use of Flexible LMA ProSeal in the Prone Position

The flexible LMA ProSeal can be safely and effectively used in adult patients positioned prone by experienced users, with insertion feasible either before or after prone positioning, though the technique requires meticulous attention to proper placement, adequate depth of anesthesia, and continuous airway monitoring.

Key Insertion Strategies

The LMA ProSeal can be inserted using two distinct approaches in prone patients:

Supine Insertion with Subsequent Prone Positioning (Traditional Approach)

• Insert the ProSeal LMA with the patient supine under adequate anesthesia 1
• Ensure proper placement and adequate seal before turning 2
• Turn patient prone with adequate personnel (typically 5 personnel required) 3
• This approach has longer surgical readiness time (approximately 22 minutes) but may be preferred by less experienced users 3

Direct Prone Insertion (Optimal Resource Utilization)

• Position patient prone first with head turned to the side and table tilted laterally 2
• Pre-oxygenate to end-tidal oxygen >90% 2
• Induce anesthesia (midazolam/alfentanil/propofol) 2
• Perform facemask ventilation to confirm airway patency 2
• Insert ProSeal LMA using digital technique as first-line approach 2
• If unsuccessful, use laryngoscope-guided or gum elastic bougie-guided insertion (single attempt each) 2
• This approach requires fewer personnel (3 vs 5) and reduces surgical readiness time to approximately 6 minutes 3

Critical Safety Requirements

Operator Experience is Paramount

• Only experienced users should attempt ProSeal LMA insertion in prone position 2, 4
• Success rates approach 100% with experienced users (237/245 successful with digital insertion, 8/245 requiring bougie-guided technique) 2
• Insertion time averages 21.8 seconds for ProSeal LMA 5

Essential Technical Considerations

• Confirm proper placement with fiberoptic bronchoscopy when available 1
• Insert gastric tube through drainage channel to decompress stomach and confirm correct positioning 2
• Achieve adequate seal pressure (mean 36 cmH₂O for ProSeal LMA) 5
• Use volume-controlled ventilation at 8-12 mL/kg 2
• Maintain adequate depth of anesthesia with volatile agent or TIVA to prevent airway stimulation 1

Ventilation Parameters and Monitoring

Effective Ventilation Characteristics

• Tidal volumes, peak airway pressures, and compliance are comparable to endotracheal intubation 6
• Leak pressures are lower than endotracheal tubes (36 cmH₂O vs 40 cmH₂O) but adequate for controlled ventilation 6, 5
• Continuous monitoring of airway patency and adequacy of breathing is essential 1

Airway Manipulation Requirements

• ProSeal LMA requires less frequent airway/neck manipulation in prone position (14.7% of patients) compared to standard SLIPA (55.9%) 6
• No patients with endotracheal tubes required manipulation, highlighting this as a relative disadvantage 6

Advantages Over Endotracheal Intubation

Reduced Airway Stimulation

• Significantly lower incidence of coughing and airway reactions during emergence and removal 6
• Beneficial for patients where cardiovascular stimulation is undesirable (neurosurgical, maxillofacial, cardiac disease) 1
• Superior emergence profile compared to awake or deep extubation with endotracheal tube 1

Aspiration Protection

• ProSeal LMA forms better seal than classic LMA and provides gastric access through drainage tube 1, 2
• Gastric tube insertion successful in 100% of cases in prone position 2

Critical Contraindications and Limitations

Absolute Contraindications

• Patients at significant risk of regurgitation or aspiration 1
• Situations where reintubation would be difficult if ProSeal LMA fails 1
• Patients with uncorrected airway pathology 1

Relative Limitations

• Obese patients may experience poor seal and airway obstruction (approximately 5% risk) 1
• Requires troubleshooting maneuvers: reinsertion, smaller size, cuff deflation, or repositioning head to sniffing position 1

Emergence and Removal Protocol

Safe Removal Technique

• Remove ProSeal LMA when patient is fully awake and able to obey commands 2
• Can be removed in prone position or after returning to supine 2
• Continue oxygen delivery until recovery is complete 1
• Lower incidence of sore throat and blood on cuff compared to endotracheal tubes 6, 3

Emergency Preparedness

Rescue Plan Essential

• Have immediate plan for airway control if ProSeal LMA fails 4
• Equipment for emergency invasive airway access must be immediately available 1
• Consider ProSeal LMA as bridge device if accidental extubation occurs in prone patient 4
• Call for help early if difficulties encountered 1

Common Pitfalls to Avoid

• Inadequate depth of anesthesia leading to laryngospasm or airway reflexes 1
• Attempting insertion without adequate experience in prone positioning 2, 4
• Failure to confirm gastric tube placement through drainage channel 2
• Using ProSeal LMA in patients with aspiration risk 1
• Excessive manipulation attempts without calling for assistance 1