What should be covered in a lecture on pediatric ventilation and intubation techniques for anesthesia residents?

Pediatric Ventilation and Intubation Techniques: A Comprehensive Review for Anesthesia Residents

I. Anatomical and Physiological Considerations

Age-Specific Positioning

For infants under 2 years, place a shoulder roll to achieve neck flexion with head extension (the "sniffing" position), while children over 2 years require only neutral head positioning without shoulder elevation. 1

• The anatomical differences between age groups necessitate distinct positioning strategies to optimize airway visualization 1
• Younger children desaturate rapidly below 94% SpO2 due to higher metabolic oxygen consumption and lower functional residual capacity 2, 3
• This rapid desaturation creates a narrow safety margin during airway management, making proper positioning critical from the first attempt 3

Critical Physiological Principles

• Neonates and infants have a delicate balance between closing volume and functional residual capacity that is easily disturbed by anesthetic interventions 4
• The younger the child, the shorter the duration of apnea without hypoxemia, making speed and efficiency paramount 2
• Positive-pressure ventilation can contribute to ventilator-induced lung injury even in healthy children, requiring careful parameter selection 5

II. Equipment Preparation and Selection

Essential Airway Equipment

Have immediately available: appropriately sized facemasks, oral and nasopharyngeal airways, supraglottic airway devices (sizes 1.5 or 2 for infants), and suction. 3

• Ensure a videolaryngoscope is available for anticipated difficult airways or after failed direct laryngoscopy 2
• Prepare cuffed endotracheal tubes rather than uncuffed tubes for all pediatric intubations 2
• Have a pressure gauge ready to monitor cuff pressures during the procedure 2

Endotracheal Tube Management

• Use cuffed endotracheal tubes and maintain cuff pressure ≤20 cm H2O to reduce re-intubation rates without increasing laryngeal complications 2
• For tonsillectomy specifically, a cuffed tracheal tube is mandatory to protect the upper airway 2
• Cuffed tubes reduce atmospheric pollution and enable low-flow ventilation techniques 2

Supraglottic Airway Devices

• Monitor cuff pressure in supraglottic airways with inflatable cuffs and limit pressure to ≤40 cm H2O 2
• Pressures exceeding 40 cm H2O increase leakage and oropharyngeal pain without improving ventilation 2

III. Routine Intubation Technique

Direct Laryngoscopy Approach

Limit direct laryngoscopy attempts to a maximum of 2 tries by the most senior practitioner present. 2

• Before each attempt, ensure: adequate depth of anesthesia, optimal head positioning (flexion of neck and extension of head), gastric decompression, and application of CPAP 2
• Check laryngoscopy technique focusing on tongue control and epiglottis visualization 2
• If glottic visualization is difficult, immediately consider using a stylet, bougie, and/or videolaryngoscope 2

Videolaryngoscopy Indications

Use videolaryngoscopy as first-line for anticipated difficult intubation with possible mask ventilation, or after failed direct laryngoscopy. 2

• Videolaryngoscopy improves glottic visualization and increases first-attempt success rates in children with polymalformative syndromes or history of difficult intubation 2
• External laryngeal maneuvers are facilitated with remote screen videolaryngoscopes as the assistant can directly visualize their effect 2
• Use a non-traumatic preformed guide to direct the tube toward the glottis when using videolaryngoscopes without a lateral channel 2

Contraindications to videolaryngoscopy: inadequate mouth opening, cervical spine fixed in flexion, or upper airway obstruction producing stridor 2

IV. Difficult Mask Ventilation Algorithm

First-Step Interventions

When mask ventilation becomes difficult, immediately administer 100% oxygen, call for help, and systematically check three domains: head position with jaw thrust, equipment integrity (mask fit, circuit, connectors), and depth of anesthesia. 2

• Add CPAP to improve ventilation 2
• Adjust cricoid pressure if being used, as it may impair ventilation 2
• Maintain optimal head positioning throughout 3

Second-Step: Airway Adjuncts

• Insert an oropharyngeal airway while maintaining CPAP 2
• Consider a nasopharyngeal airway as an alternative 2
• Exclude reversible causes: inadequate anesthetic depth, laryngospasm, or gastric inflation (decompress with oro- or nasogastric tube) 2

Third-Step: Supraglottic Airway Rescue

If ventilation remains inadequate, insert a supraglottic airway with a maximum of 3 attempts. 2

• Release cricoid pressure before supraglottic airway insertion 2
• If SpO2 remains >80% with adequate ventilation, continue anesthesia 2
• If SpO2 <80% or ventilation inadequate, assess for malposition, equipment problems, pneumothorax, or bronchospasm 2
• Consider trying a larger supraglottic airway if ventilation is inadequate 2

V. Difficult Intubation Algorithm

When Direct Laryngoscopy Fails

After 2 failed direct laryngoscopy attempts by a senior practitioner with maintained oxygenation, proceed immediately to supraglottic airway insertion (maximum 3 attempts). 2

• If supraglottic airway provides adequate oxygenation and ventilation, consider changing surgical and anesthetic strategy 2
• The supraglottic device serves dual purposes: oxygenation and as a conduit for fiberoptic-guided intubation 2
• Fiberoptic intubation through the supraglottic airway should only be performed by trained practitioners 2

Failed Supraglottic Airway Ventilation

• If SpO2 <90% despite supraglottic airway, return to optimized mask ventilation with hands 2
• Consider inserting oral or nasopharyngeal airway and decompress the stomach 2
• If mask ventilation succeeds, wake the child 2
• If all ventilation methods fail, proceed to CICO (Cannot Intubate Cannot Oxygenate) algorithm 2

VI. Cannot Intubate Cannot Oxygenate (CICO) Scenario

Initial Rescue Attempts

Continue attempting oxygenation with FiO2 100%, optimize head position with jaw thrust, insert oral/nasopharyngeal airway or supraglottic airway, ventilate with hands, and decompress the stomach. 2

Decision to Wake vs. Proceed

• If SpO2 >80%, attempt to wake the child 2
• If rocuronium or vecuronium was used, administer sugammadex 16 mg/kg 2
• Prepare for rescue techniques if the child's status continues to deteriorate 2

Emergency Front-of-Neck Access

If SpO2 <80% and/or decreasing heart rate despite all measures, call for experienced ENT surgeon and prepare for emergency tracheostomy or rigid bronchoscopy with jet ventilation. 2

• Critical warning: All cricothyroid approaches carry major risk of failure and complications in children under 8 years old; catheter-based techniques are not recommended in this age group 2
• Consider surgical cricothyrotomy only as absolute last resort 2
• Continue jet ventilation with lowest pressure possible if this route is chosen 2

VII. Rapid Sequence Induction in Pediatrics

Muscle Relaxant Selection

Use succinylcholine as first choice for rapid sequence induction; if contraindicated, use rocuronium. 2

• A rapid-onset muscle relaxant is mandatory during classic rapid sequence induction 2
• The delay between loss of consciousness and airway protection must be minimized, especially in younger children who tolerate apnea poorly 2
• Muscle relaxation significantly improves intubation conditions 2

VIII. Fiberoptic Intubation with Spontaneous Ventilation

Anesthetic Technique

For anticipated difficult intubation requiring fiberoptic guidance, use sevoflurane inhalational anesthesia as the preferred technique, maintaining spontaneous ventilation throughout. 6

• Alternative: propofol continuous infusion (bolus 0.1-0.3 mg/kg, then 0.1-0.3 mg/kg/hour) or target-controlled infusion (Schnider model, initial concentration 2.5 μg/mL, increase by 0.5 μg/mL steps) in children >5 years 6
• Use only one anesthetic agent to limit ventilatory depression 6
• Titrate dose carefully to maintain spontaneous ventilation 6

Airway Topicalization

• Apply nasal topical anesthesia with lidocaine plus naphazoline in children >2 years 6
• Perform laryngeal topical anesthesia with lidocaine 1% (1-2 mL, 2 mg/kg maximum) through the fiberoptic bronchoscope operating channel 6
• This combined approach limits airway reactivity during instrumentation 6

Oxygenation Strategies

• Use endoscopic facial mask or nasopharyngeal tube to ensure continuous oxygenation 6
• Laryngeal mask serves as rescue technique if spontaneous ventilation is lost 6

IX. Awake Supraglottic Airway Placement

Indications and Outcomes

Awake supraglottic airway placement can be considered in infants and children with significant airway obstruction or anticipated difficult intubation, achieving adequate ventilation in 85% of cases. 7

• This technique has been successfully used across all age groups, including adolescents 7
• No complications were reported with supraglottic airway placement itself 7
• Subsequent intubation achieved 35% first-attempt success and 99% eventual success 7
• Hypoxia during intubation was significantly lower when supraglottic airway ventilation was adequate (5%) versus inadequate (36%) 7

X. Ventilation Strategies and Lung Protection

Protective Ventilation Principles

Apply "open lung strategy" while avoiding inappropriately high tidal volumes and excessive oxygen administration to minimize ventilator-induced lung injury. 4

• Modern anesthesia machines offer synchronized and assisted ventilation modes that can optimize gas exchange 5
• Careful choice of ventilation modality and parameters is paramount even in healthy children 5
• Recognize that positive-pressure ventilation is potentially harmful and can contribute to both lung injury and diaphragmatic dysfunction 5

Special Considerations for Neonates

• Extremely low-birthweight infants may benefit from surgery in the NICU rather than operating theater 4
• Neonatal respiratory management requires multidisciplinary collaboration between anesthesiologists, surgeons, cardiologists, and neonatologists 4

XI. Emergence and Extubation

Timing of Supraglottic Airway Removal

• No technique (awake vs. deep removal) is superior regarding serious complications 2
• Upper airway obstruction risk is higher when removing supraglottic airways under deep anesthesia; anticipate need for jaw thrust or oropharyngeal airway insertion 2, 3
• Cough is more likely with awake removal 2
• Maintain optimal head positioning throughout emergence 3

Post-Difficult Intubation Considerations

After any difficult intubation, maintain high suspicion for laryngotracheal trauma and anticipate potentially difficult extubation. 2

XII. Common Pitfalls and How to Avoid Them

Equipment-Related Errors

• Inflating cuffs based on "clinical assessment" results in excessive pressures; always use a pressure gauge 2
• Attempting videolaryngoscopy without adequate mouth opening or in presence of upper airway obstruction leads to failure 2
• Exceeding 3 attempts at supraglottic airway insertion increases trauma risk without improving success 2

Technique-Related Errors

• Failing to optimize head position before each intubation attempt wastes precious attempts 2
• Not calling for help early enough in difficult ventilation scenarios 2
• Persisting with direct laryngoscopy beyond 2 attempts by senior practitioner delays transition to rescue techniques 2
• Using cricoid pressure during supraglottic airway insertion impairs placement success 2

Clinical Decision-Making Errors

• Attempting to intubate through a supraglottic airway without fiberoptic guidance and appropriate training 2
• Not recognizing the need to wake the child when oxygenation is adequate but intubation repeatedly fails 2
• Delaying transition to CICO algorithm when SpO2 <80% despite all conventional measures 2