What is the recommended approach for paediatric total intravenous anaesthesia (TIVA) using target-controlled infusion (TCI)?

Paediatric Total Intravenous Anaesthesia and Target-Controlled Infusion

For paediatric total intravenous anaesthesia (TIVA), target-controlled infusion (TCI) systems should be used with drug-specific, population-based pharmacokinetic models that account for age, sex, weight, and comorbidities to achieve optimal dosing and reduce complications.

Understanding Target-Controlled Infusion in Paediatrics

Target-controlled infusion (TCI) represents a sophisticated approach to TIVA in the paediatric population. Unlike traditional constant-rate infusions that may lead to drug accumulation, TCI uses mathematical models to:

• Calculate the initial dosage needed to achieve a desired drug concentration
• Make appropriate adjustments to maintain that concentration level
• Account for patient-specific characteristics affecting drug disposition

Key Components of Paediatric TCI Systems

1. Open-loop systems: Physician selects target drug concentration with no patient feedback
2. Closed-loop systems: Use real-time measures (like BIS monitoring) to regulate drug concentration based on actual effect

Recommended Drugs for Paediatric TIVA

For optimal outcomes in paediatric TIVA, the following agents are recommended:

• Primary induction agent: Propofol (rapid onset/offset pharmacokinetics ideal for TCI) 1
• Opioid options:
  • Fentanyl (3-5 μg/kg)
  • Alfentanil (10-20 μg/kg)
  • Remifentanil TCI (target concentration ≥3 ng/ml) 1
• Neuromuscular blockade:
  • Rocuronium (1 mg/kg) with appropriate neuromuscular monitoring 1

Monitoring Requirements

Continuous monitoring is essential due to pharmacodynamic variability between patients:

• Depth of anaesthesia: BIS monitoring (target 40-60) to reduce risk of awareness and avoid overdosage 1
• Neuromuscular monitoring: Should be standard of care with all muscle relaxants 1
• Hemodynamic parameters: Particularly important in paediatric patients <10 kg who are at higher risk for adverse events 1

Special Considerations for Paediatric TIVA

Age-Related Factors

• Weight <10 kg: Higher risk for adverse events; requires more careful dosing and monitoring 1
• Elderly children: May benefit from BIS monitoring to reduce risk of postoperative cognitive dysfunction 1

Procedure-Specific Considerations

• Airway procedures: TIVA allows assessment of the airway during spontaneous ventilation, essential for diagnosing dynamic airway compression 1
• Laparoscopic procedures: Deep neuromuscular block may allow operation at lower intra-abdominal pressures (10-12 mmHg) 1

Pitfalls and Caveats

1. Respiratory depression: Most concerning adverse effect of sedation in children with compromised airways 1
2. Drug combinations: May increase likelihood of adverse outcomes; use caution when combining agents 1
3. Environmental impact: While propofol TIVA has lower greenhouse gas emissions than inhalational agents, it has potential ecotoxicity in wastewater and generates plastic waste 1
4. Pharmacokinetic model limitations: Current models may not account for all paediatric variations; adjustments may be needed based on clinical response

Algorithm for Paediatric TIVA Implementation

1. Patient assessment:

   • Determine weight, age, and relevant comorbidities
   • Identify risk factors (airway pathology, oxygen dependency, weight <10 kg)

2. Equipment preparation:

   • Select appropriate TCI pump with paediatric pharmacokinetic models
   • Prepare depth of anaesthesia monitoring

3. Drug selection and dosing:

   • Calculate initial target concentrations based on age/weight
   • Prepare for potential hemodynamic effects with vasopressors available

4. Maintenance phase:

   • Adjust target concentrations based on clinical response and monitoring
   • Use closed-loop systems when available for more individualized sedation

5. Recovery considerations:

   • Ensure cardiovascular and respiratory stability before discharge
   • Be aware of potential delayed recovery of laryngeal reflexes

By following these recommendations, clinicians can effectively implement TIVA with TCI in the paediatric population while minimizing risks and optimizing outcomes related to morbidity, mortality, and quality of life.