TIVA – Total Intravenous Anesthesia

Here's a concise yet comprehensive guide to TIVA implementation in modern anesthesia practice, including common regimens, dosing, and key considerations:

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Core Components of TIVA

TIVA combines two IV agents:

1. Hypnotic: Propofol (primary).
2. Analgesic: Opioid (e.g., remifentanil, fentanyl) or adjunct (e.g., dexmedetomidine).

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Standard TIVA Regimens & Dosing

1. Propofol-Based TIVA

• Induction:
  • Propofol: 1.5–2.5 mg/kg IV (slow bolus).
• Maintenance:
  • Manual Infusion: 100–200 mcg/kg/min (titrate to BIS 40–60).
  • TCI (Target-Controlled Infusion):
    • Target plasma concentration: 3–6 mcg/mL (adjust for age/comorbidities).
    • Example: 35-year-old adult → Start at 4 mcg/mL, titrate ±0.5 mcg/mL.

2. Propofol + Remifentanil (Gold Standard)

• Induction:
  • Propofol: 1–1.5 mg/kg + Remifentanil: 0.5–1 mcg/kg IV.
• Maintenance:
  • Propofol: TCI 2–4 mcg/mL OR 50–150 mcg/kg/min.
  • Remifentanil:
    • Manual: 0.05–0.3 mcg/kg/min.
    • TCI: Target 2–6 ng/mL.
  • Key: Remifentanil allows rapid titration; stop 10–15 min before end for fast emergence.

3. Propofol + Fentanyl

• Induction:
  • Propofol: 1.5–2 mg/kg + Fentanyl: 1–2 mcg/kg IV.
• Maintenance:
  • Propofol: 100–150 mcg/kg/min.
  • Fentanyl: 0.5–1 mcg/kg/h (supplemental boluses 0.5 mcg/kg PRN).
  • Use Case: Longer surgeries (>2 hrs) where remifentanil’s cost/short action is impractical.

4. Opioid-Sparing Regimens

• Dexmedetomidine Adjunct:
  • Bolus: 0.5–1 mcg/kg over 10 min (pre-induction).
  • Infusion: 0.2–0.7 mcg/kg/h + reduced propofol (30–50% lower dose).
  • Benefits: Less hypotension, smoother emergence, opioid-sparing.

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Key Practical Considerations

1. Target-Controlled Infusion (TCI) Systems

• How it works: Uses pharmacokinetic models (e.g., Marsh, Schnider) to achieve target plasma/effect-site concentrations.
• Advantages:
  • Predictable drug levels.
  • Automatic adjustment for age/weight.
• Common Models:
  • Marsh: For propofol (weight-based).
  • Minto: For remifentanil (age/weight-adjusted).

2. Monitoring Essentials

• Depth of Anesthesia: BIS/Entropy (target 40–60).
• Hemodynamics: Beat-to-beat BP/HR (propofol causes vasodilation; remifentanil causes bradycardia).
• Ventilation: EtCO₂ and SpO₂ (apnea risk with boluses).

3. Special Populations

4. Emergence & Recovery

• Propofol: Stop 5–10 min before end.
• Remifentanil: Stop 10–15 min before end (context-sensitive half-life <5 min).
• Transition to Analgesia:
  • Give longer-acting opioid (e.g., morphine 0.1 mg/kg) 20 min before stopping remifentanil.

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Safety & Pitfalls

• Propofol Infusion Syndrome (PRIS):
  • Risk: Doses >4 mg/kg/h for >48 hrs.
  • Prevention: Limit infusion duration; monitor lactate/CK.
• Awareness:
  • Ensure BIS monitoring + double-check infusions.
• Hypotension:
  • Preload with 500 mL crystalloid; use vasopressors (e.g., phenylephrine).

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When to Choose TIVA

• Malignant Hyperthermia (MH) risk: Avoids volatile agents.
• Neurosurgery: Better cerebral perfusion control.
• PONV-prone patients: Reduced nausea vs. volatiles.
• Airway surgery: Avoids airway irritation.
• Outpatient/short cases: Faster recovery (e.g., remifentanil-based TIVA).

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Key Takeaway

TIVA = Precision Anesthesia: Use propofol TCI (2–6 mcg/mL) + remifentanil TCI (2–6 ng/mL) for most cases. Adjust for age/comorbidities, monitor BIS, and plan emergence analgesia. Always have vasopressors and rescue airway equipment ready!

Further Reading:

• ASRA Guidelines on TIVA
• OpenAnesthesia: TIVA Techniques