Pilot study of closed-loop anaesthesia for liver transplantation

Area of Science:

• Anesthesiology
• Pharmacology
• Surgical Innovation

Background:

• Automated titration of propofol and remifentanil, guided by the bispectral index (BIS), is established for many surgeries.
• Orthotopic liver transplantation (OLT) presents unique challenges including major fluid shifts, an anhepatic phase, and ischemia-reperfusion syndrome.
• The behavior of automated anesthetic titration during OLT requires specific evaluation.

Purpose of the Study:

• To assess the feasibility and performance of automated propofol and remifentanil titration guided by BIS during OLT.
• To evaluate anesthetic drug consumption across different surgical phases of OLT.
• To compare calculated drug concentrations with actual measured concentrations.

Main Methods:

• A pilot study involving adult patients undergoing OLT.
• Monitoring Bispectral Index (BIS) and automated titration of propofol and remifentanil.
• Calculating drug consumption per surgical phase (dissection, anhepatic, reperfusion) and comparing with blood sample analysis.

Main Results:

• The automated system maintained BIS within the target range (40-60) for 88% of anesthesia duration.
• Propofol requirement decreased during the anhepatic phase compared to dissection (P<0.03), while remifentanil consumption remained unchanged.
• Bland-Altman analysis indicated weak concordance for both propofol and remifentanil concentrations, with no reported adverse events.

Conclusions:

• Automated titration of propofol and remifentanil guided by BIS is feasible during orthotopic liver transplantation.
• The system demonstrated acceptable performance in maintaining target BIS values during this complex procedure.
• Further research may refine the accuracy of concentration prediction in OLT.