Overview
Definition:
The laryngeal mask airway (LMA) is a supraglottic airway device designed to create a seal around the larynx, facilitating positive-pressure ventilation
In the delivery room, its use is indicated for neonatal resuscitation when positive-pressure ventilation is required and endotracheal intubation is difficult or unsuccessful.
Epidemiology:
Neonatal respiratory distress requiring airway intervention occurs in a small percentage of births, particularly preterm infants or those with birth asphyxia
LMA use in this setting is less common than bag-mask ventilation but is a crucial second-line option.
Clinical Significance:
Effective airway management is paramount in neonatal resuscitation to ensure adequate oxygenation and ventilation, preventing hypoxic-ischemic brain injury and other complications
The LMA offers an alternative to bag-mask ventilation and endotracheal intubation, potentially improving success rates and reducing intubation-related trauma in challenging cases.
Indications And Contraindications
Indications:
Failure to achieve adequate ventilation with bag-mask ventilation after 30 seconds of effective effort
Need for positive-pressure ventilation in a non-intubated neonate
Cases where endotracheal intubation is expected to be difficult (e.g., congenital anomalies of the airway, prematurity with fragile tissues).
Contraindications:
Severe congenital anomalies of the airway or pharynx
Oral or pharyngeal obstruction
Neonates with known tracheoesophageal fistula
Gastric perforation
Severe gastroesophageal reflux disease
Impending need for definitive airway control (e.g., diaphragmatic hernia requiring immediate intubation).
Laryngeal Mask Airway Types And Selection
Available Types:
Several types of LMAs are available, including the classic LMA and newer designs like the i-Gel
For neonates, smaller sizes are crucial
The LMA sizes are typically based on weight.
Size Selection Guide:
Size 1 LMA is generally for infants < 5 kg
Size 1.5 is for infants 5-12 kg
Size 2 is for infants 12-25 kg
Always refer to the manufacturer's specific guidelines for precise weight-based selection.
Device Components:
The LMA consists of a mask, an airway tube, and an inflatable cuff
The mask is designed to sit above the glottis, forming a seal around the laryngeal inlet
The pilot balloon allows for inflation of the cuff to maintain the seal.
Insertion Technique In Neonates
Preparation:
Ensure the LMA is the correct size and is intact
Lubricate the posterior aspect of the mask
Position the neonate supine, with the neck slightly extended (sniffing position), if tolerated
Ensure adequate lighting and a clear view of the airway.
Insertion Procedure:
Hold the LMA like a pen
Depress the jaw gently
Insert the mask blindly into the pharynx, aiming towards the sternal notch, until resistance is felt
Inflate the cuff with the recommended volume of air
Connect the LMA to a ventilation circuit.
Confirmation Of Placement:
Confirm correct placement by observing chest rise with ventilation
Auscultate breath sounds bilaterally over the chest and absence of breath sounds over the epigastrium
Monitor end-tidal CO2 if available
Look for condensation in the LMA tube
Persistent gastric inflation or poor ventilation suggests malplacement.
Ventilation And Monitoring
Positive Pressure Ventilation:
Once correctly placed, use the LMA to deliver positive-pressure ventilation
The rate and pressure should be guided by neonatal resuscitation guidelines, aiming for adequate chest rise and oxygenation
Typically, a rate of 40-60 breaths per minute and appropriate pressures are used.
Monitoring Parameters:
Continuous monitoring of heart rate, respiratory rate, oxygen saturation (SpO2), and transcutaneous CO2 (if available) is essential
Observe for signs of adequate chest rise with each ventilation
Assess for any signs of airway obstruction or leak.
Troubleshooting And Reinsertion:
If ventilation is inadequate, check cuff inflation, confirm placement, and rule out obstruction
If malplacement is suspected, remove the LMA and reattempt insertion or consider alternative airway management techniques
Repeated failed attempts should prompt reassessment and consideration of endotracheal intubation.
Complications And Prevention
Potential Complications:
Sore throat or hoarseness post-insertion
Laryngospasm
Bronchospasm
Oesophageal or pharyngeal trauma
Vocal cord injury
Gastric distension
Aspiration
Airway obstruction due to secretions or malpositioning.
Prevention Strategies:
Careful selection of the correct LMA size
Gentle insertion technique to avoid trauma
Adequate cuff inflation to create a seal without excessive pressure
Thorough confirmation of placement
Prompt removal after ventilation is no longer needed
Ensuring the neonate is adequately suctioned prior to insertion.
Key Points
Exam Focus:
Understanding the indications for LMA use in neonates, correct size selection, and the steps for confirming correct placement are high-yield for DNB and NEET SS exams
Be prepared to discuss troubleshooting scenarios.
Clinical Pearls:
Always have a backup plan for difficult airways
Practice LMA insertion on manikins
Early recognition of malpositioning is crucial
LMA is a temporary airway device and should be removed as soon as feasible.
Common Mistakes:
Using the wrong size LMA
Aggressive insertion leading to trauma
Inadequate confirmation of placement
Failing to address potential complications like gastric distension
Over-reliance on LMA in cases requiring definitive airway control.