What is the recommended induction agent and dosage for pediatric patients, particularly those with a history of respiratory or cardiac disease?

Pediatric Anesthesia Induction: Agent Selection and Dosing

Recommended Induction Agents

For pediatric patients with respiratory or cardiac disease, ketamine (1-2 mg/kg IV) is the first-line induction agent due to its hemodynamic stability through sympathomimetic effects, while sevoflurane is preferred for inhalational induction in stable patients. 1, 2

Intravenous Induction Agents

Ketamine:

• Dosing: 1-2 mg/kg IV for most situations 1, 2
• Alternative dosing: 3-4 mg/kg before 18 months of age; 2 mg/kg after 18 months 3, 2
• Preferred in hemodynamically unstable patients, septic shock, or hypovolemia due to maintenance of blood pressure through sympathomimetic effects 3, 1, 2
• Particularly valuable in children with cardiac disease where blood pressure maintenance is critical 1

Etomidate:

• Dosing: 0.2-0.4 mg/kg IV (maximum: 20 mg) 1, 2
• First-choice agent in children over 2 years old, except in sepsis 3, 2
• Minimal hemodynamic effects and reduces intracranial pressure, making it useful in head injury 1, 2
• Should be avoided in septic patients due to adrenal suppression concerns 3

Propofol:

• Dosing: 2.5-3.5 mg/kg IV for children 3-16 years (ASA I-II) 4
• Reduced dosing of 1-1.5 mg/kg for ASA III-IV patients, administered as 20 mg every 10 seconds 4
• Not recommended for hemodynamically unstable patients due to significant hypotensive effects from decreased preload and afterload 1, 4
• Preferentially used in elective procedures rather than emergency situations 3

Inhalational Induction

Sevoflurane:

• Preferred inhalational agent for pediatric induction, starting at 7% maximum inspired concentration 5, 6
• Provides rapid, smooth induction with minimal airway irritation 5, 7, 6
• Recommended over desflurane in children with upper respiratory tract infections due to less airway reactivity 3
• More rapid emergence than halothane with better cardiovascular stability during induction 5, 6
• Maintenance concentration typically 1-4% (approximately 1 MAC = 2.5%) 5, 8

Premedication Requirements

Atropine Administration:

• Mandatory for children aged 28 days to 8 years, particularly those with septic shock, hypovolemia, or when succinylcholine is used 3, 1, 2
• Dosing: 0.01-0.02 mg/kg IV (maximum: 0.5 mg) 1, 2
• Prevents bradycardia from vagal stimulation during laryngoscopy and direct effects of succinylcholine 3
• Studies demonstrate reduced PICU mortality and decreased arrhythmia incidence when atropine is administered before intubation 3

Neuromuscular Blocking Agents

Succinylcholine:

• First-line agent for rapid sequence intubation in children with respiratory or cardiovascular compromise 3, 1, 2, 9
• Age-specific dosing:
  • Neonates <1 month: 1.8 mg/kg IV 1, 2, 9
  • Infants 1 month to 1 year: 2.0 mg/kg IV 1, 2, 9
  • Children 1-10 years: 1.2 mg/kg IV 1, 2, 9
  • Children >10 years: 1.0-1.5 mg/kg IV 1, 2, 9

Rocuronium:

• Alternative when succinylcholine is contraindicated (hyperkalemia, neuromuscular disease, burn patients) 3, 1, 2, 9
• Dosing: 0.9-1.2 mg/kg IV 3, 1, 2
• Higher doses (1.0-1.2 mg/kg) provide intubating conditions similar to succinylcholine at 60 seconds 3
• Sugammadex must be immediately available when rocuronium is used for potential reversal in "cannot intubate, cannot ventilate" scenarios 3, 1, 2, 9

Special Considerations for Respiratory Disease

Upper Respiratory Tract Infections:

• Sevoflurane is preferred over desflurane due to decreased airway reactivity 3
• Consider establishing IV access prior to induction in high-risk patients to allow rapid treatment of complications 3
• Propofol decreases laryngeal reactivity compared to sevoflurane, while sevoflurane decreases subglottic reactivity compared to propofol 3

Reactive Airway Disease:

• Avoid desflurane due to increased bronchial reactivity 3
• Sevoflurane provides bronchodilation and is well-tolerated 3

Special Considerations for Cardiac Disease

Hemodynamic Management:

• Ketamine is strongly preferred due to maintenance of sympathetic tone and blood pressure 3, 1
• Propofol causes dose-dependent decreases in preload and afterload, risking decompensation in cardiac patients 4
• Slow administration is critical: 20 mg every 10 seconds if propofol must be used, avoiding rapid bolus 4
• Anticipate need for anticholinergic agents as propofol reduces heart rate through decreased sympathetic activity 4

Common Pitfalls and Caveats

Critical Errors to Avoid:

• Failure to administer atropine in children under 8 years, especially with succinylcholine use, significantly increases risk of severe bradycardia and mortality 3, 1, 2
• Using succinylcholine in patients with contraindications (hyperkalemia, neuromuscular disease, burns >24 hours old) can cause fatal cardiac arrest 9
• Rapid bolus administration in hemodynamically unstable or elderly patients causes severe hypotension, apnea, and oxygen desaturation 4
• Failure to have sugammadex available when using rocuronium leaves no reversal option in failed intubation scenarios 3, 1, 2
• Using propofol as first-line in unstable patients rather than ketamine risks cardiovascular collapse 1, 4

Pain on Injection:

• Propofol causes significant pain in pediatric patients (45% incidence) when administered through small hand veins 4
• Pretreat with lidocaine 1 mL of 1% solution or use antecubital veins to reduce pain to <10% incidence 4
• Maximum lidocaine addition: 20 mg per 200 mg propofol to maintain emulsion stability 4

Emergence Agitation:

• Sevoflurane and desflurane are associated with postoperative agitation and delirium 7, 6
• More rapid emergence with sevoflurane may result in earlier and more intense postoperative pain compared to halothane 6