초록 ▼

Patient airway baseline pressure levels are controlled in a ventilator having a pneumatically controlled exhalation valve without an external supply of pilot pressure, by supplying an internal source of controllable pilot pressure for operating the exhalation valve. The pressure of pressurized air s

Patient airway baseline pressure levels are controlled in a ventilator having a pneumatically controlled exhalation valve without an external supply of pilot pressure, by supplying an internal source of controllable pilot pressure for operating the exhalation valve. The pressure of pressurized air supplied by an internal pump can be electrically controlled by pulse width modulation of a variable pulse duration signal. A second source of pressurized air for pilot pressure is provided, and in one embodiment is a reservoir provided for receiving pressurized air from the pump and from the exhalation circuit. A valve is connected to the pump means and the reservoir for receiving pressurized air from the pump in a first position, and for receiving pressurized air from the reservoir in a second position. When the valve means is in the second position, pressurized air is delivered at a pressure which is the greater of the pressurized air supplied by the pump means or the gas flow from the exhalation circuit.

대표청구항 ▼

An apparatus for controlling gas flow through an exhalation circuit of a lung ventilator for controlling airway pressure in a patient airway connected to the exhalation circuit, comprising: a pneumatically operated exhalation valve for controlling flow of gas through said exhalation circuit; a pump

An apparatus for controlling gas flow through an exhalation circuit of a lung ventilator for controlling airway pressure in a patient airway connected to the exhalation circuit, comprising: a pneumatically operated exhalation valve for controlling flow of gas through said exhalation circuit; a pump for supplying a first source of pressurized air; a second source of pressurized air; a pump control for controlling the pressure of pressurized air supplied by said pump means; a valve connected to said pump and said second source of pressurized air, said valve having a first position in fluid communication with said pump for receiving pressurized air from said pump, and a second position in fluid communication with said second source of pressurized air for receiving pressurized air from said second source of pressurized air, said valve having an outlet connected to a pilot pressure line in fluid communication with said exhalation valve to deliver pressurized air through said pilot pressure line to said exhalation valve for operation of said exhalation valve; and a valve control for switching said valve between said first and second positions.