RESPIRATING APPARATUS FOR PATIENTS

Abstract: Respirating apparatus comprising a pump (1,2,3) , by means of which respiratory gas may be circulated in a closed line system (4) in which the pressure may be varied in accordance with a certain respirating pattern, said line system (4) being provided with connecting means (8) for a patient and for supplying the various components of the respiratory gas (10,11,12) and with means (9) for withdrawing the carbon dioxyde exhaled by the patient into the line system (4), said pump including at least one pump chamber (1,2,3), which is separated by a pump membrane (5) into a primary and a secondary portion, in which the secondary portion forms part of or is connected to the line system (4) and the primary portion is connected to a supply of a driving fluid (17), of which the varying pressure may effect the pumping action of the membrane (5).

Description: The present invention relates to a respirating apparatus for patients, more particularly for anesthesia, comprising a closed line system that is provided with a first pump by means of which respiratory gas may be circulated in said closed line system and with a second pump by means of which the respiratory gas in said closed line system may be alternately compressed and decompressed to make the patient respire in accordance with a certain respiratory pattern, the closed line system being provided with means for connecting said closed line system with the patient and with further connecting means for supplying the various components of the respiratory gas to said closed line system and with still further means for withdrawing carbon dioxide that has been exhaled by the patient into the closed line system. The FR-A-1 532 030 (see preamble of Claim 1) discloses a respiration apparatus with a closed line system in which the respiratory gas may alternately compressed and decompressed by means of a breathing bag enclosed in a housing which is connected to a supply of compressed air whose pressure may be varied to effect a pumping action of the bag. This known apparatus has the disadvantage of being complicated, and in addition the discharge of the bag and the control of the pressure in the line system cannot be performed with great accuracy. It is an object of the present invention to obviate this disadvantage of the known apparatus. The apparatus according to the invention thereto is characterized in that the second pump includes a plurality of simultaneously operable pump chambers connected in parallel with one another, each pump chamber having a flexible membrane which extends completely across said chamber and which separates said chamber into a primary and a secondary portion, the secondary portion of each pump chamber being connected to the closed line system and the primary portion of each pump chamber being connected to a supply of compressed air whose pressure may be varied to effect a pumping action of the membrane, and a plurality of externally controllable valves located respectively between said compressed air supply and the primary portions of said pump chambers and between the secondary portions of said pump chambers and said closed line system for selectively varying the number of said parallel pump chambers that are simultaneously operative to effect a pumping action at any given time thereby to control the pressure of the respiratory gas being circulated in said closed line system. In an embodiment of the invented apparatus means are provided for determining the membrane displacement and the volume change related thereto of the secondary portion of each pump chamber. These means may be differently shaped. In a favourable embodiment of the apparatus according to the invention, the means may act in a capacitive or inductive manner. According to a further feature of the invented apparatus the membrane movement towards the secondary portion of each pump chamber is limited to an end position by a stop member present in the primary portion of said pump chamber while further the rest position of the membrane is determined by a stop member present within the primary portion of each pump chamber. An embodiment of the invention will now be described by way of example only with reference to the accompanying drawing. As is shown in the drawing, the apparatus is provided with a membranepump with three pump chambers 1, 2 and 3, connected in parallel, and by means of which the respiratory gas in a closed conduit system 4 may be alternately compressed according to a certain respiratory pattern. Each of the pump chambers 1, 2 and 3 is divided by a membrane 5 into a primary portion, which is connected to a supply/discharge 6 for compressed air being the driving fluid, and a secondary portion, which is connected to the closed line system 4. The line system 4 further is provided with connecting means 8 for the patient, with an absorbing device 9 to withdraw the carbon dioxyde exhaled by the patient into the line system, with connections 10, 11 and 12 for introducing into the line system laughing gas (N O) and oxygen, and with an evaporator with a supply 7 for liquid anesthetica. The secondary portions of the pump chambers 1, 2 and 3 are connected to the line system 4 via valves 13, whilst the primary portions of the pump chambers 1, 2 and 3 are connected via valves 14 to a supply/discharge 6 for the compressed air. The line system further comprises the circulation pump 15 to circulate and to mix the components of the respiratory gas in the line system 4. The supply/discharge line 6 of the compressed air is connected via an electro-magnetically operatable valve 16 and a control valve, which is not shown in the drawing, to a compressed air supply 17, and via an electro-magnetically operatable valve 18 to a compressed air discharge or blow off line 19. The secundary portions of the pump chambers 1,2 and 3 are provided with measuring devices (not shown in the drawing), by means of which the displacements of the membranes may be measured and introduced into a central control/regulation device (computer) 20. When in operation, the composition of the respiratory gas, such as the concentrations of oxygen, laughing gas, carbon dioxyde and the like are determined continuously in a manner known in itself and also introduced into the central control/regulation device 20, which on account of the received information, regulates the supply of laughing gas, oxygen, and the like in the line system, as well as the control of the valves 16 and 18, and eventually of the valves 13 and 14 to make the patient to respire according to a certain pattern.

Claims: Respirating apparatus for patients, more particularly for anesthesia, comprising a closed line system (4) that is provided with a first pump (15) by means of which respiratory gas may be circulated in said closed line system and with a second pump (1, 2, 3) by means of which the respiratory gas in said closed line system may be alternately compressed and decompressed to make the patient respire in accordance with a certain respiratory pattern, the closed line system being provided with means (8) for connecting said closed line system with the patient and with further connecting means (10, 11, 12) for supplying the various components of the respiratory gas to said closed line system and with still further means (9) for withdrawing carbon dioxide that has been exhaled by the patient into the closed line system, characterized in that the second pump includes a plurality of simultaneously operable pump chambers (1, 2, 3) connected in parallel with one another, each pump chamber having a flexible membrane (5) which extends completely across said chamber and which separates said chamber into a primary and a secondary portion, the secondary portion of each pump chamber being connected to the closed line system and the primary portion of each pump chamber being connected to a supply of compressed air (17) whose pressure may be varied to effect a pumping action of the membrane, and a plurality of externally controllable valves (13, 14) located respectively between said compressed air supply and the primary portions of said pump chambers and between the secondary portions of said pump chambers and said closed line system for selectively varying the number of said parallel pump chambers that are simultaneously operative to effect a pumping action at any given time thereby to control the pressure of the respiratory gas being circulated in said closed line system. Apparatus as claimed in claim 1, characterized in that means are provided for determining the membrane displacement and the volume change related thereto of the secondary portion of each pump chamber. Apparatus as claimed in claim 1, characterized in that the membrane movement towards the secondary portion of each pump chamber is limited to an end position by a stop member present in the primary portion of said pump chamber. Apparatus as claimed in claim 1, characterized in that the rest position of the membrane is determined by a stop member present within the primary portion of each pump chamber. Apparatus as claimed in claim 1, characterized in that means (7) are provided for directly introducing into the closed line system and to evaporate therein a liquid anestheticum.

Inventors: VAN DIJK, GEERT, WESTERKAMP, BART
Applicants: PHYSIO BV
Application year: 1988
Main classification: A61M16
IPC codes: A61M16