What are the requirements for a tubeless Total Intravenous Anesthesia (TIVA)?

Requirements for Tubeless Total Intravenous Anesthesia (TIVA)

Tubeless TIVA requires maintaining spontaneous ventilation with propofol and remifentanil infusions, continuous depth of anesthesia monitoring, immediate airway rescue capability, and careful patient selection to ensure adequate oxygenation without endotracheal intubation. 1

Essential Anesthetic Requirements

Drug Selection and Dosing

• Administer propofol via continuous infusion targeting effect-site concentration of 0.5-1 mcg/ml to maintain adequate sedation while preserving spontaneous ventilation 2
• Combine with remifentanil continuous infusion at 1-3 ng/ml effect-site target for analgesia without excessive respiratory depression 2
• Avoid bolus dosing of either propofol or remifentanil during maintenance, as this significantly increases risk of apnea and loss of spontaneous ventilation 2
• Consider superior laryngeal nerve block in approximately 50% of cases to reduce anesthetic requirements and improve airway tolerance 1

Mandatory Monitoring Equipment

• Processed EEG monitoring (BIS or Entropy) targeting BIS 40-60 is essential to prevent awareness while avoiding excessive depth that could suppress spontaneous ventilation 2
• Continuous monitoring of heart rate, blood pressure, and pulse oximetry throughout the procedure 3
• Capnography to detect hypoventilation or apnea immediately 1
• BIS values should rise above 90 within approximately 4 minutes after stopping propofol infusion to allow patient arousal if needed 4

Immediate Airway Rescue Capability

• Have endotracheal intubation equipment immediately available at bedside, as 9-12% of cases may require transient supplemental ventilation 1
• Maintain capability for rapid conversion to mask ventilation, endotracheal ventilation, or jet ventilation if hypoventilation or desaturation occurs 1
• Ensure anesthesia provider remains present and focused solely on airway management throughout the procedure 1

Patient Selection Criteria

Suitable Candidates

• ASA physical status I-III patients without significant cardiopulmonary disease 1
• Patients requiring unobstructed surgical access to the larynx or airway where an endotracheal tube would interfere with the procedure 4, 1
• Cooperative patients who can follow commands for intraoperative voice monitoring if required 4
• Procedures with expected duration under 3 hours to minimize risk of propofol accumulation 1

Relative Contraindications

• Patients with known difficult airway anatomy where emergency intubation would be challenging 1
• Severe obesity with confirmed obstructive sleep apnea, as these patients have higher risk of airway obstruction during spontaneous ventilation 2
• Patients with baseline hypoxemia or significant pulmonary disease who cannot tolerate brief periods of hypoventilation 1
• Hemodynamically unstable patients, as propofol decreases cardiac output and blood pressure in a dose-dependent manner 3

Hemodynamic Management

Vasopressor Preparation

• Have vasopressors immediately available (ephedrine or metaraminol) before starting propofol infusion 2
• Propofol causes dose-dependent decreases in cardiac output, systemic vascular resistance, and arterial pressure 3
• Elderly and debilitated patients have exaggerated hemodynamic responses requiring more cautious dosing 3

Fluid Management

• Target euvolemia throughout the procedure 5
• Avoid both hypovolemia (which exacerbates propofol-induced hypotension) and fluid overload 5

Procedural Technique Considerations

Anesthesia Depth Titration

• Maintain BIS around 60 during continuous propofol administration to preserve spontaneous ventilation while ensuring adequate sedation 4
• When patient arousal is needed (e.g., for voice monitoring), interrupt propofol infusion and expect BIS to exceed 90 within 234 seconds on average 4
• Resume propofol administration after completing the portion requiring patient cooperation 4

Ventilation Management

• Allow completely spontaneous ventilation without positive pressure support 1, 6
• Average operative time achievable is 73 minutes (range 27-166 minutes) under tubeless TIVA 1
• Approximately 91% of cases can be completed successfully without requiring conversion to alternative ventilation 1

Recovery and Emergence

Postoperative Advantages

• Tubeless TIVA demonstrates shorter postoperative fasting time compared to intubated general anesthesia 6
• Reduced postoperative pain scores due to absence of endotracheal tube trauma 6
• Shorter mean duration of postoperative hospital stay, with 56-83% of cases achievable as day surgery depending on procedure type 6
• Significantly reduced postoperative nausea and vomiting compared to volatile anesthetics 2, 7

Emergence Protocol

• Ensure return of adequate tidal volumes and airway reflexes before discontinuing monitoring 2
• For obese patients, insert nasopharyngeal airway before full emergence if they have confirmed sleep apnea 2
• Reinstate home CPAP immediately upon return to ward if patient uses it 2

Critical Safety Pitfalls

Common Complications and Management

• Hypoventilation or desaturation occurs in approximately 12% of cases and requires immediate intervention with mask ventilation, endotracheal ventilation, or jet ventilation 1
• Propofol infusion rates exceeding 4 mg/kg/hour significantly increase risk of hypotension and should be avoided unless benefits clearly outweigh risks 3
• Pain on injection occurs in up to 30% of patients receiving propofol boluses; use larger veins or add lidocaine (maximum 20 mg lidocaine per 200 mg propofol) 3
• Avoid propofol in patients with egg, soy, or sulfite allergies due to risk of severe reactions 3