Somministrazione di Isoflorano con un sistema di infusione TCI Close Loop per anestetici volatili in un circuito rotatorio in cavalli

CONTEX: Nowadays there is a increasing needs for cheap and environmentally friendly technologies. Volatile anaesthetics agents, such as Isoflurane and Sevoflurane are potent greenhouse gases. Anaesthetists can give their contribute to decrease earth worming by cutting volatile anaesthetics agents pollution into the atmosphere. Today an important factor of the inhalant anaesthesia is the cost of it. The mean cost of an hour Isoflorane anaesthesia is 22 € OBJECTIVE: To find a safe and cheap method to cut the use of volatile anaesthetics agents anaesthetizing large animal species. A TCI Closed Loop Infusion system was built and tested in order to improve its performances. After six month of testing the system was ready to be used. DESIGN: We made 10 anaesthesias in 9 horses. The volatile agent (Isoflurane) was injected directly into the breathing system as a liquid, using an infusion pump controlled by a computer in which a self produced software was installed. The system injected a pre-calculated dose of Isoflorane due to fill the circuit (Prime Dose). Afterwards the PC worked out the dose needed every minute (Unit Dose) receiving the ETISO value from a respiratory gas monitor connected with the breathing system. All data were statistically analyzed to validate the system. The data collected were also compared with what was the standard practice to the Department of Veterinary Clinical Science in Legnaro. 27 anaesthesia records coming from previous anaesthesias carried out at our department were found meeting the inclusion criteria, in all of them Isoflurane was delivered by using a vaporizer. The Isoflurane consumes in the first ten minutes and in the first hour were calculated from the selected records. RESULTS: The consumption of Isoflorane in the first 10 minutes was 7,6 ml (SD± 1,6) and after an hour was 19,17ml (SD± 8,27), while using the vaporizer, in the first 10 minute the amount of Isoflorane was 17,43 mL (SD± 5,54) and after an hour was 46,96 mL (± 13,26). Bias and Accuracy were -3,6 % and 5,29 % respectively. CONCLUSION: The system tested saved almost 60% of Isoflorane compared the standard practice.