Patent ID: 6523537
Filing Date: 2003-02-25
Classification: A61M

Abstract:
A method of automatic control for the supply of a volatile anaesthetic to a closed anaesthetic circuit of low flow, which comprises the stage of mixing fresh gas and volatile anaesthetic before introducing the mixture into the patient, the method comprising the steps of:a) setting a ventilatory rate (VR) of the patient; b) automatically setting a flow of fresh gas (FFG) to 10% of the VR; c) determining a fraction inhaled (% IF) and exhaled (% EF) by the patient of volatile anaesthetic; d) setting a dial of an anaesthetic vaporiser to a value resulting from multiplying by 10 a differential of the inhaled fraction (% IF) and exhaled fraction (% EF) of volatile anaesthetic by the patient, wherein a concentration of anaesthetic at an output of the anaesthetic vaporizer (% dial) is equal to (% IFâˆ’% EF)Ã—10, and changing, in a same proportion, the opening of said dial every time that said differential of inhaled fraction (% IF) and exhaled fraction (% EF) of volatile anaesthetic by the patient varies; e) supplying a quantity of anaesthetic to a circuit (QASC) that covers at least a total quantity of anaesthetic consumed by the patient (TQAC) by means of opening of the dial of the anaesthetic vaporizer; and f) mixing the quantity of anaesthetic with the FFG before introducing said mixture into the patient.