Why are laryngeal mask airways (LMAs) used in pediatric patients?

Why Laryngeal Mask Airways Are Used in Pediatric Patients

Laryngeal mask airways (LMAs) are used in pediatric patients because they significantly reduce perioperative respiratory complications compared to endotracheal intubation, particularly decreasing the risk of laryngospasm and bronchospasm by up to 5-fold in infants and young children undergoing appropriate surgical procedures. 1, 2

Primary Indications for LMA Use in Children

Reduced Respiratory Complications

• The French Society of Anesthesia and Intensive Care provides a Grade 2+ recommendation with strong expert agreement favoring LMA over endotracheal tubes for short-lasting elective superficial surgery in children. 2
• A randomized controlled trial in 181 infants aged 2-12 months demonstrated that endotracheal intubation carries a 2.94-fold increased relative risk of perioperative respiratory adverse events compared to LMA. 1, 2
• The relative risk of laryngospasm and bronchospasm is 5 times greater with endotracheal intubation versus LMA in this population. 1, 2
• Meta-analyses consistently show significantly lower incidence of postoperative cough with LMA compared to endotracheal tubes. 1

Ease of Insertion and Less Trauma

• LMA insertion is easier than endotracheal intubation, with 94% successful easy placement for LMA versus only 53% for endotracheal tubes in pediatric patients. 3
• First-attempt success rates for LMA insertion reach 85.2% in children, demonstrating reliability as a supraglottic airway device. 4
• LMA avoids the need for laryngoscopy, causes less respiratory tract trauma, and results in less soft tissue injury compared to endotracheal intubation. 5, 3

Hemodynamic Stability

• Hemodynamic changes (heart rate, blood pressure) are significantly lower with LMA placement compared to endotracheal intubation. 3
• These hemodynamic perturbations persist for shorter duration with LMA (3 minutes) versus endotracheal intubation (5 minutes). 3

Specific Clinical Scenarios

Routine Elective Surgery

• LMA is appropriate for short-duration superficial procedures in healthy children (ASA I-II status). 1
• LMA provides effective positive pressure ventilation in children weighing 10-20 kg undergoing elective surgery. 3
• Even in laparoscopic procedures with pneumoperitoneum, LMA maintains adequate ventilation with no significant difference in leak volume or end-tidal CO2 compared to endotracheal tubes. 6

Children with Upper Respiratory Infections

• When facemask ventilation is precluded in children with URI, LMA is associated with less desaturation compared to endotracheal tubes, though superiority regarding laryngospasm remains debated. 1
• Common pitfall: LMA carries risk of misplacement and stimulation-induced laryngospasm under inadequate anesthesia depth in URI patients. 1

Difficult Airway Management

• LMA serves as a critical rescue device in unanticipated difficult intubation scenarios, recommended as the second step after failed direct laryngoscopy when mask ventilation remains adequate. 1
• French guidelines recommend maximum 3 insertion attempts before considering alternative strategies. 1, 2
• LMA is incorporated into difficult pediatric airway algorithms as an essential supraglottic airway device. 5

Diagnostic Procedures

• LMA provides excellent airway control for pediatric fiberoptic bronchoscopy under general anesthesia, allowing BAL and mucous plug extraction with oxygen saturation >95% in all patients. 7
• LMA offers superior patient comfort compared to endotracheal intubation for diagnostic procedures. 7

Technical Considerations

Proper Sizing and Pressure Management

• Monitor LMA cuff pressure with a manometer and limit to ≤40 cmH₂O to minimize oropharyngeal pain while optimizing seal. 2
• Size selection must accommodate appropriate bronchoscope size when used for diagnostic procedures. 7
• Predictors of first-attempt failure include: abnormal airway anatomy (91% failure rate), body weight <16 kg, age <5 years (44% failure), and use of size 1 or 1.5 LMA (3.8% failure). 4

Device Removal Strategy

• No evidence supports superiority of either deep anesthesia or fully awake removal regarding serious complications (laryngospasm or desaturation). 1
• Deep removal carries increased risk of upper airway obstruction, but this is easily managed with jaw thrust or oral airway insertion. 1
• Awake removal results in more coughing but may be preferred to avoid obstruction risk. 1

Absolute Contraindications

When NOT to Use LMA

• For tonsillectomy, a cuffed endotracheal tube is mandatory (Grade 1+ recommendation with strong agreement) to protect the upper airway from blood and surgical debris. 1
• LMA cannot overcome functional airway problems or mechanical airway obstruction in children. 5
• Full stomach situations require endotracheal intubation for aspiration protection. 5

Comparative Complication Rates

Documented Advantages Over Endotracheal Tubes

• Laryngospasm: 6.1% with LMA versus 22.9% with endotracheal tubes (p<0.05). 6
• Desaturation: 12.2% with LMA versus 37.5% with endotracheal tubes (p<0.05). 6
• Severe coughing: 6.1% with LMA versus 27% with endotracheal tubes (p<0.05). 6
• Bronchospasm incidence significantly lower with LMA across multiple studies. 1, 3