Oxygen availability during orthotopic liver transplantation

Area of Science:

• Anesthesiology
• Transplantation Medicine
• Physiology

Background:

• Adequate tissue oxygenation is vital for patient outcomes and allograft survival in liver transplantation.
• Conventional hemodynamic monitoring may not fully capture real-time oxygen availability.
• The oxyhemoglobin dissociation curve (ODC) and its shift (P50) influence oxygen release to tissues.

Purpose of the Study:

• To evaluate real arterial available oxygen content (CavlO2) and its extraction ratio (O2ERavl) during liver transplantation.
• To assess the impact of oxyhemoglobin dissociation curve (ODC) shifts (P50) on oxygen availability.
• To determine if P50 provides a more accurate measure of oxygen release than conventional parameters.

Main Methods:

• Prospective study involving 16 adult cirrhotic patients undergoing orthotopic liver transplantation with venovenous bypass.
• Collected data included classic hemodynamic measurements, arterial and mixed venous blood gas analysis.
• Calculated P50, oxygen delivery index (DO2 ind), oxygen consumption index (VO2 ind), oxygen extraction ratio (O2ER), CavlO2, and O2ERavl.

Main Results:

• A leftward shift in the ODC was observed, with P50 decreasing intraoperatively.
• A positive association was found between P50 and CavlO2 after native liver removal.
• Conventional oxygen delivery index (DO2 ind) showed weak correlations with other variables.

Conclusions:

• Intraoperative changes in P50, indicating ODC shifts, may more accurately estimate tissue oxygen release than hemoglobin, PaO2, and SaO2 alone.
• P50, by accounting for ODC alterations, could enhance systemic oxygenation monitoring during liver transplantation.
• Integrating P50 alongside conventional parameters may improve patient outcomes and allograft viability.