How to transition a stable adult or pediatric patient from TIVA with propofol to inhalational anesthesia with sevoflurane (sevoflurane) intraoperatively?

Transitioning from TCI Propofol to Sevoflurane Intraoperatively

To transition from propofol TCI to sevoflurane inhalation during surgery, begin sevoflurane at 2-3% in oxygen/air while simultaneously reducing the propofol infusion by 50%, then discontinue propofol completely once end-tidal sevoflurane reaches 1.5-2% (approximately 5-10 minutes), maintaining depth of anesthesia monitoring with BIS 40-60 throughout the transition. 1

Practical Transition Algorithm

Step 1: Pre-Transition Preparation

• Ensure adequate vascular access and hemodynamic stability before initiating the transition, as both agents cause vasodilation and their effects may be additive during the overlap period 2
• Have vasopressors immediately available (ephedrine or metaraminol) to manage potential hypotension during the transition 3, 2
• Verify that depth of anesthesia monitoring (BIS or processed EEG) is functioning and displaying values between 40-60 4, 3

Step 2: Initiate Sevoflurane

• Start sevoflurane at 2-3% concentration in oxygen/air mixture through the anesthesia circuit 5
• Maintain adequate minute ventilation to facilitate rapid uptake of sevoflurane 5
• Monitor end-tidal sevoflurane concentration continuously, targeting 1.5-2% (approximately 1 MAC for adults) 5

Step 3: Reduce Propofol Infusion

• Once sevoflurane is initiated, immediately reduce the propofol TCI target by 50% or reduce the infusion rate by half 2
• Continue monitoring BIS to ensure adequate depth of anesthesia remains between 40-60 during this overlap period 4, 3
• Observe for signs of lightening anesthesia (increased heart rate, blood pressure, movement) which would indicate inadequate sevoflurane uptake 5

Step 4: Discontinue Propofol

• After 5-10 minutes, when end-tidal sevoflurane reaches 1.5-2%, completely discontinue the propofol infusion 5
• The timing depends on the patient's age, as sevoflurane requirements are age-dependent (higher concentrations needed in younger patients) 5
• Continue to monitor BIS values, adjusting sevoflurane concentration to maintain BIS 40-60 4, 3

Critical Monitoring During Transition

Hemodynamic Management

• Monitor blood pressure continuously during the transition, as both propofol and sevoflurane cause vasodilation through different mechanisms 2, 6
• Expect potential additive hypotensive effects during the overlap period when both agents are present 2
• Treat hypotension promptly with vasopressors rather than fluid boluses if the patient is euvolemic 1
• Heart rate may increase during the transition, particularly if transitioning from propofol/remifentanil to sevoflurane/fentanyl combinations 6

Depth of Anesthesia

• Maintain BIS monitoring between 40-60 throughout the entire transition to prevent both awareness and excessive depth 4, 3
• Propofol has rapid offset (context-sensitive half-time increases with duration of infusion), so depth may decrease quickly once infusion is stopped 5
• Sevoflurane has relatively rapid onset compared to other volatile agents, but still requires 5-10 minutes to reach steady-state brain concentrations 5

Common Pitfalls and How to Avoid Them

Pitfall 1: Premature Discontinuation of Propofol

• Avoid: Stopping propofol before adequate end-tidal sevoflurane is achieved (minimum 1.5% in adults) 5
• Risk: This creates a gap in anesthetic coverage, potentially leading to awareness or inadequate anesthesia 4
• Solution: Maintain propofol at reduced rate until end-tidal sevoflurane confirms adequate brain concentration 5

Pitfall 2: Inadequate Hemodynamic Preparation

• Avoid: Initiating transition in hypovolemic or hemodynamically unstable patients 1, 2
• Risk: Severe hypotension from additive vasodilatory effects of both agents 2, 6
• Solution: Optimize volume status before transition and have vasopressors drawn up and ready 1, 3

Pitfall 3: Ignoring Age-Dependent Requirements

• Avoid: Using the same sevoflurane concentration targets for all age groups 5
• Risk: Inadequate anesthesia in younger patients or excessive depth in elderly patients 5
• Solution: Adjust sevoflurane concentration based on age (higher in pediatric patients, lower in elderly), using BIS monitoring as guide 4, 5

Special Considerations

Airway Surgery Context

• Propofol TIVA is often preferred for tracheal surgery because it doesn't irritate the airway and allows "tubeless" field during critical portions 4
• If transitioning to sevoflurane during airway surgery, ensure the airway is secured and surgery is not at a critical phase where coughing from volatile agent could be problematic 4
• Sevoflurane has nonpungent odor and causes less respiratory irritability than other volatile agents, making it the preferred volatile agent if transition is necessary 5, 7

Postoperative Implications

• Be aware that transitioning from propofol to sevoflurane may increase postoperative nausea and vomiting (PONV) risk 1, 8, 6
• Consider administering multimodal PONV prophylaxis if transition occurs, particularly in high-risk patients (female, non-smoker, history of PONV) 1
• Recovery time may be shorter with sevoflurane compared to propofol in some contexts, though this depends on duration of propofol infusion 8, 6

Clinical Context for Transition Decision

When Transition May Be Indicated

• Equipment failure or malfunction of TCI pump requiring alternative anesthetic technique 1
• Prolonged surgery where volatile agent may be more practical or economical 1
• Specific surgical requirements (e.g., need for rapid adjustment of anesthetic depth) 5
• Institutional or regional availability considerations, as sevoflurane is considered an essential medicine by WHO 1

Evidence on Comparative Outcomes

• There is no strong evidence recommending one maintenance technique over another for major postoperative outcomes including complications, mortality, or length of stay 1
• Both propofol TIVA and sevoflurane maintenance are safe and effective for most surgical procedures 1, 5, 9
• The choice between maintaining with propofol versus transitioning to sevoflurane should prioritize patient-specific factors, surgical requirements, and clinical judgment rather than routine practice 1