Automatic calibration method of anesthesia apparatus tidal volume

Abstract

The invention relates to a method for automatically calibrating the tidal volume of an anesthetic machine, comprising the following steps that: firstly, the respiratory frequency and the respiratroy quotient of the anesthetic machine are set; secondly, an initial point and a plurality of intermediate flow rate points are selected as index points within a calibrated flow rate range; thirdly, the value of the tidal volume is obtained through calculation of a formula V=FT; fourthly, a calibrated tidal volume measuring device is used as reference to search for calibrated tidal volumes one by one and automatically save PWM values of searched tidal volumes; fifthly, a fitting curve chart of the flow rate L and the PWM values is established by utilization of the calibrated tidal volumes according to the set respiratory frequency, the set respiratroy quotient and the corresponding flow rate calculated in the formula of the third step; the flow rate value can be calculated according to the set tidal volume under the condition of the set respiratory frequency and the set respiratroy quotient; and the PWM value at the time can be calculated according to the fitting curve chart to control the flow rate, thereby the method realizes automatic calibration of the tidal volume and avoids affection of the dead space volume of devices, the aperture of pipes, the self weight of windboxes and the external factors on calibration of the tidal volume.

Description

technical field [0001] The invention relates to a calibration method, in particular to an automatic calibration method for the tidal volume of an anesthesia machine used for changing the tidal volume exhaled by a patient in a medical anesthesia ventilator. Background technique [0002] The tidal volume of existing anesthesia machines is generally controlled by a proportional flow control valve. The proportional solenoid valve controls the opening of the throttle valve or the throttle port of the speed control valve through the input signal PWM to realize continuous or proportional control of the tidal volume. amount of output flow. The opening of the orifice is determined by the voltage PWM of the input signal of the proportional solenoid valve. The proportional flow control valve is mainly used for open loop control. The output of the proportional control valve is proportional to the input signal PWM, and The magnetic force generated by the electromagnetic coil in the prop...

AI Technical Summary

Problems solved by technology

[0004] However, due to the device dead space and pipeline air resistance at the tidal volume at the exhalation end and the proportional flow control end, the existing automatic calibration method simulates the pipeline by increasing the proportional coefficient to simulate the dead space of the device and adding an air resistance device to the proportional flow control valve. Air resistance is used to adjust the tidal volume at the exhalation end, but in fact, the dead space volume of the device, the diameter of the pipe, the weight of the bellows and some external factors are difficult to completely simulate, and often cause a large error, so only by increasing the ratio Coefficients and air-blocking devices are not enough