[Evaluation of low-flow sevoflurane anesthesia using modified Engström Elsa Anesthesia System]

Area of Science:

• Anesthesiology
• Chemical Engineering
• Toxicology

Background:

• Sevoflurane is a widely used inhalation anesthetic.
• The Engström Elsa anesthesia system was modified to allow sevoflurane administration.
• Low-flow anesthesia techniques aim to reduce anesthetic gas consumption and waste.

Purpose of the Study:

• To evaluate the safety and feasibility of low-flow sevoflurane anesthesia using a modified Engström Elsa anesthesia system.
• To detect and quantify breakdown products of sevoflurane during anesthesia.
• To assess for clinical or laboratory evidence of organ toxicity in patients.

Main Methods:

• Modification of the Engström Elsa anesthesia system for sevoflurane delivery.
• Administration of low-flow sevoflurane anesthesia to 10 surgical patients.
• Monitoring of sevoflurane breakdown products (Compound A and Compound B) and clinical/laboratory parameters for organ toxicity.

Main Results:

• Compound A (CF2=C(CF3)OCH2F) was detected at 14.0 +/- 7.8 ppm after the first hour, remaining stable for 7 hours.
• Compound B (CH3OCF2CH(CF3)OCH2F) was detected in 3 patients at concentrations below 0.5 ppm.
• No patient exhibited clinical or laboratory signs of hepatic or renal toxicity.

Conclusions:

• Low-flow sevoflurane anesthesia using the modified Engström Elsa system is safe and feasible.
• Detected levels of sevoflurane breakdown products did not correlate with adverse clinical outcomes or organ dysfunction.
• This modified system offers a potentially safe and effective option for low-flow sevoflurane anesthesia.