Patent Application
20200282170
The present invention relates to an oxygen concentration device used for a general anesthesia machine, for example, for a person, or an animal such as a cat or a dog, and an oxygen concentration method.
Conventionally, an oxygen gas having a concentration of 100% has been used for general anesthesia using an anesthesia machine. However, in recent years, the adverse effect of anesthesia with pure oxygen is known, and an oxygen concentration of the oxygen gas to be inhaled of about 60% is regarded as preferable.
In order to supply the oxygen gas having an oxygen concentration of about 60% to a patient, a nitrogen gas or compressed air (sterile and low-humidity one) is separately prepared and mixed into oxygen to produce gas having an oxygen concentration of about 60%.
Further, when awakening from anesthesia at the finish of an operation, the oxygen concentration is further decreased, the patient is made to inhale oxygen having a low concentration close to the oxygen concentration of the atmosphere and adapts his or her body to the oxygen, thereby securing safety.
Patent document 1: International Publication No. WO 2016/098180
However, in the aforementioned method, it is necessary to separately prepare nitrogen or compressed air which is difficult to obtain on a daily basis and it is difficult to employ the method because of a problem in cost or the like at a site such as animal hospitals or the like.
Hence, in consideration of the above problem, an object of the present invention is to provide an oxygen concentration device and an oxygen concentration method capable of arbitrarily adjusting the concentration of an oxygen gas to be supplied to an anesthesia machine in a range of about 25 to 90% using an oxygen concentrator used for an ordinary oxygen treatment.
A first invention is an oxygen concentration device including: a compressor configured to supply atmospheric air; an oxygen concentration unit configured to generate concentrated oxygen from the air supplied by the compressor; and a flow rate adjustment unit configured to purge a part of the concentrated oxygen suppliable from the oxygen concentration unit to an anesthesia machine, into the atmosphere, wherein the flow rate adjustment unit adjusts a flow rate of the concentrated oxygen to be purged into the atmosphere to control an oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine.
In this case, it is preferable to further include a flowmeter capable of measuring the flow rate of the concentrated oxygen to be purged from the flow rate adjustment unit into the atmosphere.
A second invention is an oxygen concentration method including: a concentrated oxygen generation step of generating concentrated oxygen in an oxygen concentration unit from air supplied by a compressor; and a purge step of a flow rate adjustment unit purging (releasing) a part of the concentrated oxygen suppliable from the oxygen concentration unit to an anesthesia machine, into the atmosphere, wherein at the purge step, a flow rate of the concentrated oxygen to be purged (released) into the atmosphere is adjusted to control an oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine.
In this case, it is preferable that at the purge step, the flow rate of the concentrated oxygen to be purged (released) into the atmosphere is measurable by a flowmeter.
According to the present invention, the cost required for oxygen, nitrogen or compressed air used for the anesthesia machine can be significantly reduced and safe anesthesia can be executed and thus widely employed at the medical site.
An oxygen concentration device and an oxygen concentration method according to an embodiment of the present invention will be explained.
As illustrated in
The compressor 12 is a supply source which supplies atmospheric air to the downstream side.
The heat exchanger 14 is intended to lower the temperature of compressed air which has been compressed by the compressor 12 and reached high temperature. When the fan 16 is driven, the air-cooled heat release effect can be obtained.
For the air controller 18, for example, a through valve manifold is employed. For the through valve manifold, four through valves are combined, and two valves are operated in each cycle to send air and exhaust nitrogen. The operation of the through valve manifold repeats a first cycle and a second cycle in a period of a predetermined time or a predetermined pressure. The operation cycle differs depending on the power supply frequency and the flow rate.
The pair of oxygen concentration units 20A, 20B each include, for example, a casing and zeolite housed in the casing. This is also called a molecular sieve and has an ability of separating molecules depending on the size of the molecule. Zeolite absorbs nitrogen and allows oxygen to pass therethrough. The reason is that the size of the nitrogen molecule is relatively large and is thus captured in the hole of zeolite, whereas the size of the oxygen molecule is relatively small and is thus not captured in the hole of zeolite. As a result of this, when the compressed air passes through zeolite, oxygen and nitrogen in the air are separated, so that nitrogen is absorbed in zeolite and concentrated oxygen is generated.
The generated concentrated oxygen is stored in the concentrated oxygen tank 22, and controlled by the pressure adjustment unit 24 to a predetermined value, and then branched at an outlet of the flow rate adjustment unit 30A.
In other words, on the outlet side of the flow rate adjustment unit 30A, two routes such as a first flow path 36 and a second flow path 38 are provided. An anesthesia machine 28 is connected to the first flow path 36, and the second flow path 38 is opened to the atmosphere via the other flow rate adjustment unit 30B.
Here, the relationship between the oxygen concentration and the flow rate will be considered.
As illustrated in
However, if the concentrated oxygen is supplied to the anesthesia machine 28 at a high flow rate, concentrated oxygen containing an anesthesia component other than the concentrated oxygen consumed by the patient is simultaneously exhausted in the operating room, possibly resulting in interference with an appropriate medical practice by a doctor, medical staff and so on.
From the above reason, it is necessary to avoid the supply of the concentrated oxygen at a flow rate more than necessary to the anesthesia machine 28.
The anesthesia machine 28 is intended to provide anesthetic effects to the patient, and the concentrated oxygen at a predetermined concentration is supplied to the anesthesia machine 28. The flowmeter 26A and a flow rate adjustment unit 27A are provided closely to or integrally with the anesthesia machine 28 and can adjust the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28.
The flow rate adjustment unit 30B of the second flow path 38 is similarly provided with the flowmeter 26B.
Note that the flow rate adjustment units 30A, 30B adjust the flow rates of gas flowing through the flow paths.
Next, the operation of the oxygen concentration device and the oxygen concentration method according to the embodiment will be explained.
As illustrated in
The concentrated oxygen supplied to the first flow path 36 is supplied to the patient via the anesthesia machine 28 while the flow rate is being appropriately adjusted by the flow rate adjustment unit 27A.
The concentrated oxygen supplied to the second flow path 38 is purged into the atmosphere while the flow rate is being appropriately adjusted by the flow rate adjustment unit 30B.
Here, the relationship between the flow rate and the concentration of the concentrated oxygen is illustrated in
As explained above, when the concentrated oxygen having a high concentration of, for example, 90% is taken into the body of the patient for a long time, the concentrated oxygen conversely generates a harmful effect. Therefore, it has been necessary to increase the flow rate of the concentrated oxygen to decrease the concentration of the concentrated oxygen to be supplied to the patient.
However, at the time when the flow rate of the concentrated oxygen is is increased, the concentrated oxygen which has not been consumed by the patient but remains of the concentrated oxygen containing the anesthesia component is released into the operating room via a relief valve installed in the anesthesia machine 28 to lead to a risk of interference with the medical practice by the medical personnel.
Therefore, a part of the concentrated oxygen to be supplied from the concentrated oxygen tank 22 is intentionally made to pass through the second flow path 38 and purged into the atmosphere not via the anesthesia machine 28, thereby making it possible to simultaneously reduce the flow rate and the oxygen concentration of the concentrated oxygen to be supplied to the patient through the first flow path 36 and via the anesthesia machine 28.
In the present invention, because the oxygen concentration of an oxygen gas to be supplied to the anesthesia machine is diluted, compressed air and nitrogen gas become unnecessary.
Note that a code 32 denotes an orifice, and a code 34 denotes a PE valve.
Next, an experimental example of the oxygen concentration method in the embodiment will be explained.
An experiment for confirming how the oxygen concentration of the concentrated oxygen supplied to the anesthesia machine 28 changes according to the change in flow rate value of the concentrated oxygen purged into the atmosphere by adjusting the flow rate adjustment unit 30B illustrated in
In this experiment, as illustrated in
As illustrated in
At the flow rate of the concentrated oxygen purged from the second flow path 38 into the atmosphere of 12 L/min, the oxygen concentration of the concentrated oxygen was 40% in the case where the flow rate of the concentrated oxygen supplied to the anesthesia machine 28 was 2 L/min and the oxygen concentration of the concentrated oxygen was 35% in the case where the flow rate was 5 L/min.
At the flow rate of the concentrated oxygen purged from the second flow path 38 into the atmosphere of 23 L/min, the oxygen concentration of the concentrated oxygen was 30% in the case where the flow rate of the concentrated oxygen supplied to the anesthesia machine 28 was 2 L/min and the oxygen concentration of the concentrated oxygen was 29% in the case where the flow rate was 5 L/min.
At the flow rate of the concentrated oxygen purged from the second flow path 38 into the atmosphere of 30 L/min, the oxygen concentration of the concentrated oxygen was 25% in the case where the flow rate of the concentrated oxygen supplied to the anesthesia machine 28 was 2 L/min and the oxygen concentration of the concentrated oxygen was 23% in the case where the flow rate was 5 L/min.
It was turned out from the above result that the relationship between the flow rate of the concentrated oxygen supplied to the anesthesia machine 28 and the oxygen concentration was that when the flow rate of the concentrated oxygen supplied to the anesthesia machine 28 was increased (2 L/min→5 L/min), the oxygen concentration of the concentrated oxygen decreased by the value of the flow rate of the concentrated oxygen purged from the second flow path 38 into the atmosphere. This has proved that when the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28 is increased, the oxygen concentration of the concentrated oxygen decreases.
It has been further proved that when the value of the flow rate of the concentrated oxygen to be purged from the second flow path 38 into the atmosphere is increased, the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28 decreases. This has proved that the value of the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28 has the same tendency at 2 L/min and 5 L/min.
However, it has been proved that when the value of the flow rate of the concentrated oxygen to be purged from the second flow path 38 into the atmosphere is increased, the difference in the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28 decreases between the magnitudes (values at 2 L/min and 5 L/min) of the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28. In other words, it has been turned out that when the flow rate value of the concentrated oxygen to be purged from the second flow path 38 into the atmosphere is increased, the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28 tends to converge to decrease to a certain value irrespective of the value of the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28.
As explained above, it has been turned out that the purge of the concentrated oxygen from the anesthesia machine 28 into the atmosphere greatly contributes to a decrease in the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28.
It has been turned out, on the above premise, that when the flow rate of the concentrated oxygen to be supplied to the anesthesia machine 28 is increased, the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28 decreases irrespective of the magnitude of the flow rate value of the concentrated oxygen to be purged from the second flow path 38 into the atmosphere.
It has been further turned out that when the flow rate value of the concentrated oxygen to be purged from the second flow path 38 into the atmosphere is increased, the oxygen concentration of the concentrated oxygen to be supplied to the anesthesia machine 28 converges to decrease to a certain value irrespective of the magnitude of the flow rate value of the concentrated oxygen to be supplied to the anesthesia machine 28.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-132120 | Jul 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/020562 | 5/29/2018 | WO | 00 |
