| 摘要 |
1488358 Patient ventilator apparatus SANDOZ Ltd 24 Sept 1974 [28 Sept 1973] 41604/74 Heading AST [Also in Division F2] A fluidically controlled patient ventilator comprises a, patient breathing hose 28 connected to a bellows apparatus 10 for supplying a predetermined quantity of air to the hose, and a control circuit comprising a fluidic flip flop 60 switchable into first and second states to control the bellows in inspiratory and expiratory phases respectively, a fluidic inspiration timer 80, a fluidic expiration timer 74, a fluidic trigger circuit 72 which provides a switching signal to the flip flop in response to a minimum pressure in the hose, a fluidic pressure limit circuit 78 coupled to the hose, a volume limit signal generator 32, 34, 36, and a switch 58 for de-energising the trigger circuit or the exhalation timer. In addition, there is provided a manually operable inspiration triggering device 70 and a manually operable expiration triggering device 76. In a "control" mode of operation, the flip flop is switched to effect an inspiratory phase by a signal from expiration timer 74 or from manual device 70, the trigger circuit 72 being de-energised, the inspiratory cycle being terminated by a signal from manual device 76, pressure limit circuit 78, the volume limit signal generator, or inspiration timer 80. In an "assist" mode, switching to the inspiratory phase is effected by a signal from the trigger circuit 72 or from manual device 70, the expiration timer being de-energised; while in an "assist/control" mode both trigger circuit 72 and expiration timer 74 are energised. Display devices 82, 86, 90 indicate respectively the output of a signal from the pressure limit circuit, the inspiration timer, and the trigger circuit. The ratio of the inspiratory to the expiratory phase may be adjusted by means of an adjustable by-pass valve 120 associated with the inspiration timer. A conduit 122 is provided for coupling to a nebulizer device, the nebulizer being operable intermittently or continuously. Oxygen from a source 46 energises the control circuit and is used to pressurize a bellows chamber 14 to cause the collapse of a bellows therein to supply air to the patient hose. On expansion of the bellows, oxygen is forced out of the chamber 14 and through a mixing valve 44 where it is mixed with air and then supplied to the bellows. The oxygen from the bellows chamber may however be vented to atmosphere through valve 44. |
