초록 ▼

A volume ventilator is disclosed which has a balloon valve type exhalation valve for permitting release of gases to the ambient environment during the exhalation period of artificial ventilation or spontaneous breathing, or when there is excess proximal pressure in the ventilator system. A pressure

A volume ventilator is disclosed which has a balloon valve type exhalation valve for permitting release of gases to the ambient environment during the exhalation period of artificial ventilation or spontaneous breathing, or when there is excess proximal pressure in the ventilator system. A pressure transducer continuously senses the proximal pressure in the ventilator system and sends to a microcomputer controller and associated circuitry of the ventilator system a signal indicative of the instantaneous proximal pressure. The pressure in the balloon, which is the pilot pressure of the exhalation valve, is regulated through a jet venturi type pressure controller which is connected to a source of pressurized gas. The gas flows through the jet venturi, wherein its flow rate is regulated by a ball valve moving against a suitable valve seat. The ball valve is controlled by a stepper motor through a cam follower. The stepper motor is controlled through electronic signals generated in the computer control in response to the difference between the instantaneously sensed proximal pressure, and the pilot pressure required to be present in the balloon in accordance with an algorithm or preselected pilot pressure-versus-time function. Accurate servo control of the flow of respiratory gas to the patient is accomplished by a flow control subsystem which incorporates a flow control valve controlled by a second stepper motor. The flow of the respiratory gas is monitored, downstream of the flow control valve, by a flow transducer. The flow transducer sends to the microcomputer controller a signal indicative of the instantaneous flow rate of the respiratory gas. The microcomputer controller compares the instantaneous flow rate to a flow rate value required by an algorithm or preselected flow rate-versus-time function stored in its memory. The microcomputer controller then sends a signal to the second stepper motor to adjust the flow control valve to provide the flow rate instantaneously required by the preselected function or algorithm.

대표청구항 ▼

In a ventilator system for providing artificial ventilation to a patient including a pressure regulated source of respiratory gas; flow control means for controlling the flow of the respiratory gas to the patient in accordance with a predetermined flow rate-versus-time function; flow sensing and tra

In a ventilator system for providing artificial ventilation to a patient including a pressure regulated source of respiratory gas; flow control means for controlling the flow of the respiratory gas to the patient in accordance with a predetermined flow rate-versus-time function; flow sensing and transducer means for measuring the flow rate of the respiratory gas downstream of the flow control means and for generating a first electric signal indicative of said flow rate; exhalation valve means in fluid communication with the flow of the respiratory gas and with the patient for providing an outlet to the ambient to proximal gases of the patient; pressure control means operatively connected with the exhalation valve means for controlling the exhalation valve means to maintain the proximal pressure in accordance with a predetermined pressure-versus-time function; and computer means for receiving the first electric signal, for providing the predetermined flow rate-versus-time function, for comparing the value required by the predetermined flow rate-versus-time function to the instantaneous flow rate as indicated by the first electric signal, and for generating and sending a corrective second electric signal to the flow control means to regulate the flow control means, the improvement comprising: a stepper motor included in the flow control means and having a rotatable shaft, an asymmetric cam mounted to the rotatable shaft and a cam follower operatively mounted to follow the cam in a substantially linear motion, the stepper motor being controlled by the corrective second electric signal, and an adjustable flow control valve included in the flow control means and having an orifice interfacing with a valve body which is connected to the cam follower, whereby the stepper motor controls the flow rate.