JP5930291B2 - Hollow fiber membrane oxygenator - Google Patents

Description

  The present invention relates to a hollow fiber membrane oxygenator for performing gas exchange (supply of oxygen, discharge of carbon dioxide) to blood during extracorporeal circulation, and more particularly to improvement of the structure of the blood outflow region after gas exchange.

  In cardiac surgery, a heart-lung machine is used to stop the patient's heart and perform the respiratory and circulatory functions during that time. Artificial lungs provide an extracorporeal blood circulation by supplying oxygen to blood instead of a patient's lungs and discharging carbon dioxide. As examples of the oxygenator, a bubble oxygenator and a hollow fiber oxygenator (membrane type) oxygenator are known. The hollow fiber membrane oxygenator is configured such that a gas containing oxygen and blood flow through a porous hollow fiber membrane, and gas exchange is performed between the blood and the gas. Since the hollow fiber membrane oxygenator has advantages such as less blood damage and a smaller priming amount than the bubble oxygenator, the hollow fiber membrane oxygenator is becoming popular in recent years.

  FIG. 7 shows a cross-sectional view of the oxygenator disclosed in Patent Document 1 as an example of a hollow fiber oxygenator. In this oxygenator, a heat exchange unit 20, a gas exchange unit 21, and a filter unit 22 are arranged in order from the upstream side through which blood flows.

  The heat exchanging unit 20 includes a plurality of tube bodies 23 through which cold / hot water for temperature adjustment flows, and adjusts the temperature of the blood before flowing into the gas exchanging unit 21. The gas exchange unit 21 is provided with a plurality of hollow fiber membranes 24, and gas exchange is performed between the oxygen-containing gas flowing in the hollow fiber membranes 24 and blood. The filter unit 22 includes a discharge channel 25 for guiding the blood that has passed through the gas exchange unit 21 to the outside, and a sheet-like filter member 26 that can capture bubbles in the blood is disposed.

  In the housing 27 in which the heat exchange unit 20, the gas exchange unit 21, and the filter unit 22 are accommodated, a seal member 28 is provided to form a blood channel 29. The housing 27 is provided with blood introduction ports 30 and blood discharge ports 31 located at both ends of the blood flow path 29. The housing 27 is further provided with gas ports 32 and 33 and cold / hot water ports 34 and 35.

  The blood flowing in from the blood introduction port 30 crosses the heat exchange part 20 and the gas exchange part 21 and flows out from the blood discharge port 31. Meanwhile, the heat exchange unit 20 exchanges heat with cold / hot water, and the gas exchange unit 21 exchanges gas with the oxygen-containing gas.

  When using such an artificial lung device, priming is performed in advance with a priming solution such as physiological saline in order to remove air and foreign substances from the blood circuit and to make the hollow fiber of the gas exchange unit familiar with the liquid. Then, blood circulation is performed. However, even if priming is performed, bubbles may be mixed into the blood during blood circulation, and therefore, the oxygenator is required to have a function of removing bubbles. If such a function is provided, priming can be completed in a short period, which is effective in emergency medicine.

  In order to obtain the function of removing bubbles, the oxygenator shown in FIG. 7 is provided with an air discharge line 36. The air discharge line 36 is formed between the gas exchange unit 21 and the filter member 26 so that the discharge flow path 25 and the outside communicate with each other. An opening on the inlet side of the air discharge line 36 is provided on the wall surface of the discharge flow path 25, and an opening on the outlet side is provided on the outer surface of the housing 27. Thus, by providing the air discharge line 36, the air bubbles 37 before reaching the filter member 26 or the air bubbles 37 captured by the filter member 26 can be discharged to the outside.

JP 2010-2000884 A

  The configuration for removing the air bubbles 37 by the air discharge line 36 disclosed in Patent Document 1 has a problem as shown in FIG. FIG. 8 is a cross-sectional view schematically showing only the hollow fiber membrane 24, the discharge channel 25, and the air discharge line 36 in order to explain the problem.

  When the artificial lung priming operation is performed, air accumulates in the upper region 38 of the blood discharge port 31. Therefore, by providing the air discharge line 36 as in the configuration disclosed in Patent Document 1, it is possible to reliably discharge the air in this portion. During priming, the tube 39 connected to the air discharge line 36 is opened to remove the air in the upper region 38 on the outlet side.

  On the other hand, when the priming is completed, the tube 39 is clamped to block the air discharge line 36 from the outside so that it can be used for extracorporeal blood circulation. As described above, the air discharge line 36 is necessary only during priming, and is not necessary during extracorporeal blood circulation. Rather, when blood circulation is started, the air discharge line 36 becomes a blood retention part and triggers the formation of a thrombus.

  Accordingly, an object of the present invention is to provide a hollow fiber membrane oxygenator having a structure that reliably discharges air during priming and does not generate a retention portion even during blood circulation.

The hollow fiber membrane oxygenator of the present invention has, as a basic structure, a housing that forms a gas exchange part in which a bundle of a plurality of hollow fiber membranes is arranged, and a gas containing oxygen through the lumen of the hollow fiber membrane. A gas port provided in the housing so as to circulate, a blood channel that circulates blood so as to cross the hollow fiber bundle in the gas exchange part and contact the outer surface of the hollow fiber membrane, and the blood channel blood introduction port from an outer wall surface of the housing at both ends of the tubular that is provided so as to respectively protrude, and includes a blood outlet port.

In order to solve the above-mentioned problems, the hollow fiber membrane oxygenator of the present invention is characterized in that the blood discharge port is a base-end opening that is a joint portion with the outer shell wall of the housing, and the base-end opening The proximal end side opening includes an uppermost peripheral edge of the cross section of the flow channel, which is a cross section of the blood flow channel, and an upper end portion of the blood flow channel. provided so as to extend in the extending direction of the channel, before Kisaki end, extends from the upper end or its vicinity of the proximal-side opening, the tube axis direction, the flow path of the blood channel An angle θ that is inclined upward in a vertical plane including the central axis, and that forms a direction downstream of the tube axis of the blood discharge port with respect to a direction downstream of the flow path central axis, It is set within the range of 0 <θ <90.

  According to the hollow fiber membrane oxygenator having the above-described configuration, the blood discharge port is opened at a place where air is likely to stay, and the blood discharge port is inclined upward. Air is reliably discharged from the air. This eliminates the need for a special air discharge line. Therefore, formation of a blood retention part in the blood circulation can be reduced, and formation of a thrombus can be suppressed.

Side view of hollow fiber membrane oxygenator in an embodiment of the present invention Front view of the hollow fiber membrane oxygenator Rear view of the hollow fiber membrane oxygenator Plan view of the hollow fiber membrane oxygenator Sectional drawing which shows the cross section seen in the same direction as FIG. 1 of the hollow fiber membrane type artificial lung Schematic perspective view for explaining an appropriate condition of the relationship between the cross-sectional shape of the blood flow path of the hollow fiber membrane oxygenator and the position of the outlet port Sectional drawing which shows the hollow fiber membrane type artificial lung of a prior art example Schematic cross-sectional view for explaining problems of conventional hollow fiber membrane oxygenator

  The hollow fiber membrane oxygenator of the present invention can take the following aspects based on the above configuration.

  That is, it is preferable that the angle θ is set to be in a range of 45 ≦ θ <90.

  Further, the outer peripheral edge shape of the cross section of the blood flow path is defined as an outer peripheral edge on both sides of the uppermost end, with the intersection of the vertical plane including the flow path center axis and the outer peripheral edge of the flow path cross section being the highest peripheral edge. It can be set as the structure located below the said uppermost periphery. In this case, the outer peripheral edge shape of the cross section of the blood flow path can be circular.

  Further, in the housing, a heat exchanging portion in which a thin tube bundle composed of a plurality of heat transfer thin tubes is arranged along the blood flow path and upstream of the gas exchange portion is provided. A heat medium liquid port through which the heat medium liquid flows in and out can be provided in the housing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment>
A side view of a hollow fiber membrane oxygenator according to an embodiment of the present invention is shown in FIG. This oxygenator has a structure in which a heat exchange part 2 and a gas exchange part 3 are formed in a housing 1 and elements for heat exchange and gas exchange are accommodated, respectively. FIG. 2 is a front view seen from the heat exchanging unit 2 side. Accordingly, FIG. 1 corresponds to the right side view of FIG. FIG. 3 is a rear view of the hollow fiber membrane oxygenator, and FIG. 4 is a plan view. FIG. 5 is a cross-sectional view showing a cross section viewed in the same direction as FIG.

  A blood channel 4 (shown only in FIG. 5) having a circular cross section is formed by penetrating the lumen formed by the heat exchange unit 2 and the gas exchange unit 3 in the horizontal direction. A blood introduction port 5 and a blood discharge port 6 are respectively provided on the outer shell wall of the housing 1 corresponding to both ends of the blood flow path 4. Cold and hot water ports 7 and 8 for circulating cold water or hot water are provided on the outer shell walls of the housing 1 at the left and right ends of the heat exchanging portion 2 downward. Gas ports 9 and 10 for introducing and deriving oxygen-containing gas are provided on the outer shell walls of the housing 1 at the upper and lower ends of the gas exchange unit 3, respectively.

  As shown in FIG. 5, a bundle of stainless steel pipes 11 is arranged in the inner cavity of the heat exchanging section 2 as a heat transfer thin tube for heat exchange with the tube axis oriented in the horizontal direction. Cold / hot water flows into and out of the stainless steel pipe 11 via the cold / hot water ports 7 and 8. A hollow fiber bundle formed of a plurality of hollow fiber membranes is disposed in the lumen of the gas exchange unit 3 with the tube axis oriented in the vertical direction. However, in the figure, illustration of the hollow fiber bundle is omitted, and the region where the hollow fiber membrane is disposed is indicated by hatching, and this will be referred to as the hollow fiber membrane 12 and will be described. A gas containing oxygen flows into and out of the lumen of the hollow fiber membrane 12 through the gas ports 9 and 10.

  The housing 1 in the outer peripheral area of the heat exchange unit 2 and the gas exchange unit 3 is filled with a seal member 13 with both ends of the stainless pipe 11 and the hollow fiber membrane 12 exposed. The lumen of the seal member 13 forms the blood flow path 4 and extends across the stainless steel pipe 11 and the hollow fiber membrane 12 in the horizontal direction. Thereby, blood flows in contact with the outer surfaces of the stainless steel pipe 11 and the hollow fiber membrane 12.

  As shown in FIG. 2, a circular transparent window 14 is provided on the front side of the housing 1, but the illustration of the stainless steel pipe 11 seen through in this region is omitted. As shown in FIG. 3, a circular transparent window 15 is also provided on the back side of the housing 1. In this region, ribs 16 extending radially from the center are formed on the inner surface of the outer shell wall of the housing 1 as shown in FIG. However, illustration of the hollow fiber membrane 12 seen through in this region is omitted.

  In the above configuration, blood flowing from the blood introduction port 5 passes through the blood flow path 4 extending from the heat exchange unit 2 to the gas exchange unit 3 and flows out from the blood discharge port 6. Cold water or hot water, which is a heat exchange liquid flowing in from the cold / hot water inlet port 8, enters the lumen from one end of each stainless steel pipe 11 and flows out from the cold / hot water outlet port 7 via the other end of each stainless steel pipe 11. . Meanwhile, heat exchange is performed with the blood in the heat exchange unit 2. On the other hand, the oxygen-containing gas flowing from the gas inlet port 9 enters the lumen from one end of each hollow fiber membrane 12 and flows out from the gas outlet port 10 via the other end of each hollow fiber membrane 12. In the meantime, gas exchange is performed with the blood in the gas exchange unit 3. The blood that has undergone the gas exchange flows while being guided by the ribs 16 so as to smoothly flow into the blood discharge port 6.

  As shown in FIG. 1, FIG. 3, or FIG. 5, the present embodiment is characterized in that the blood discharge port 6 is inclined upward. That is, the distal end portion of the blood discharge port 6 is tubular, but is inclined upward in a vertical plane including the flow channel central axis A (FIG. 5) of the blood flow channel 4.

  Further, as shown in FIG. 5, an upper space 17 is formed in the proximal end side opening portion which is a connecting portion of the blood discharge port 6 to the outer shell wall of the housing 1. The upper space 17, that is, the proximal end side opening of the blood discharge port 6, is set so as to include the uppermost peripheral edge T of the flow path cross section that is a cross section of the blood flow path 4.

  The inclination of the blood discharge port 6 is defined as follows. That is, the shape of the distal end portion of the blood discharge port 6 is an angle θ formed by the direction toward the downstream of the tube axis B of the blood discharge port 6 with respect to the direction toward the downstream of the flow channel central axis A of the blood flow channel 4. Is set in a range of 0 <θ <90. In order to obtain the following effects sufficiently and reliably, the angle θ is preferably set to be within a range of 45 ≦ θ <90.

  By configuring the blood discharge port 6 as described above, air can be smoothly discharged through the blood discharge port 6 during priming. That is, the air collected in the upper space 17 by the flow of the priming liquid flows out smoothly because the blood discharge port 6 is inclined upward.

  Moreover, since the blood discharge port 6 functions as it is during extracorporeal blood circulation, the operation of clamping the tube to seal the air discharge line after priming is unnecessary. Therefore, the presence of the blood retention portion due to the presence of the air discharge line as in the conventional example is eliminated.

  It is desirable that the outer peripheral shape of the cross section of the blood flow path 4 is a shape that is concentrated in the blood discharge port 6. As an example, the shape is schematically shown in FIGS. 6 (a) and 6 (c). In (a), the blood flow path 4 has a circular cross section as in the above-described embodiment. In (c), blood channel 4a has a square cross section, and is arranged such that one vertex is the uppermost peripheral edge and the diagonal vertex is positioned vertically downward. (B) is an inappropriate example, and the blood channel 4b has a square cross section, but is arranged so that one side faces in the horizontal direction. In this shape, the effect of air discharge from the blood discharge port 6 is limited.

  Thus, the outer peripheral edge shape of the flow path cross section of the blood flow path 4 concentrated in the blood discharge port 6 is the intersection of the vertical plane including the flow path center axis and the outer peripheral edge of the flow path cross section. The outer peripheral edge on both sides of the uppermost end is defined as a shape located below the uppermost peripheral edge.

  In the above description, the hollow fiber membrane oxygenator having the configuration in which the heat exchange part 2 and the gas exchange part 3 are formed by the housing 1 is shown as an example, but the application of the present invention is not limited to this. That is, even with a hollow fiber membrane oxygenator having only the gas exchange part 3 without the heat exchange part 2, the same effect as described above can be obtained by applying the structure of the blood discharge port 6 described above. it can.

  The hollow fiber membrane oxygenator of the present invention is useful as an oxygenator for extracorporeal blood circulation because air is reliably discharged during priming and no retention portion is produced even during blood circulation.

1, 27 Housing 2, 20 Heat exchange part 3, 21 Gas exchange part 4, 4a, 4b, 29 Blood flow path 5, 30 Blood introduction port 6, 31 Blood discharge port 7, 8, 34, 35 Cold / hot water port 9, 10, 32, 33 Gas port 11 Stainless steel pipe 12, 24 Hollow fiber membrane 13, 28 Seal member 14, 15 Transparent window 16 Rib 22 Filter part 23 Tube 25 Discharge flow path 26 Filter member 36 Air discharge line 37 Bubble 38 Upper part Region 39 tube

Claims (5)

A housing forming a gas exchange part in which a bundle of a plurality of hollow fiber membranes is disposed;
A gas port provided in the housing to circulate a gas containing oxygen through the lumen of the hollow fiber membrane;
A blood flow path for circulating blood so as to traverse the hollow fiber bundle in the gas exchange section and to contact the outer surface of the hollow fiber membrane;
It said blood flow passage at both ends of the housing outer wall surface to provided a tubular blood inlet port to each projecting from, and, in the hollow fiber membrane oxygenator having the blood discharge port,
The blood discharge port is composed of a base end side opening which is a coupling site with the outer shell wall of the housing, and a tubular tip end connected to the base end side opening.
The proximal end side opening is provided so as to include the uppermost peripheral edge of the cross section of the flow channel which is a cross section of the blood flow channel, and the upper end portion thereof extends in the extending direction of the blood flow channel,
Before Kisaki end, extends from the upper end or its vicinity of the proximal-side opening, the tube axis direction, upwardly in a vertical plane containing the flow path center axis of the blood channel slope The angle θ formed by the direction toward the downstream of the tube axis of the blood discharge port with respect to the direction toward the downstream of the flow path center axis is set within a range of 0 <θ <90. A hollow fiber membrane oxygenator characterized by that.   The hollow fiber membrane oxygenator according to claim 1, wherein the angle θ is set to be in a range of 45 ≦ θ <90.   The outer peripheral edge shape of the cross section of the blood flow path has an intersection of a vertical plane including the flow path center axis and the outer peripheral edge of the flow path cross section as the uppermost peripheral edge, and the outer peripheral edges on both sides of the uppermost end are The hollow fiber membrane oxygenator according to claim 1, which is located below the uppermost peripheral edge.   The hollow fiber membrane oxygenator according to claim 3, wherein an outer peripheral edge shape of a cross section of the blood channel is circular. In the housing, a heat exchanging portion in which a thin tube bundle composed of a plurality of heat transfer thin tubes is disposed on the upstream side of the gas exchanging portion along the blood flow path,
The hollow fiber membrane oxygenator according to claim 1, wherein a heat medium liquid port through which the heat medium liquid flows in and out through the heat transfer thin tube is provided in the housing.

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