Optimal Fresh Gas Flow when Employing Total Intravenous Anesthesia

Area of Science:

• Anaesthesiology and Perioperative Medicine
• Environmental Science and Sustainability
• Health Economics

Background:

• Fresh gas flow (FGF) in total intravenous anaesthesia (TIVA) is not linked to anesthetic delivery, impacting costs and environmental footprint.
• Higher FGF reduces CO2 absorber use but overall economic and environmental trade-offs remain unclear.
• A context-specific calculator is needed to determine optimal FGF during TIVA in various clinical settings.

Purpose of the Study:

• To develop a calculator for estimating optimal FGF during TIVA.
• To assess the economic and environmental impacts of different FGF settings.
• To provide an evidence-based tool for balancing cost and environmental considerations in TIVA.

Main Methods:

• Life-cycle assessment (LCA) to quantify environmental impact (GWP100) and costs of oxygen, air, and CO2 absorbers.
• Modeling annual costs and GWP100 across FGFs (1-10 L/min) and FiO2 (30-60%).
• Development of a web-based calculator incorporating context-specific parameters like grid emissions factors (GEF).

Main Results:

• In our institution, increasing FGF reduced costs but non-linearly increased GWP100.
• Cost savings plateaued beyond 2-4 L/min FGF.
• Globally, the FGF minimizing GWP100 was highly dependent on GEF, with higher FGF beneficial only at very low GEF values.

Conclusions:

• Optimal FGF during TIVA is context-dependent, influenced by GEF and CO2 absorbent disposal.
• Our calculator offers evidence-based suggestions for FGF, balancing economic and environmental factors.
• The tool aids clinicians in making informed decisions for sustainable anaesthetic practices.