Fluid reservoir for an aspiration line of a medical system

Abstract

The invention relates to a fluid reservoir (313) for an aspiration line of a medical system, wherein the aspiration line serves to suction a fluid in a suction direction from a surgical site on a living being by means of a fluid pump of the medical system, comprising a sleeve (314) which encloses a chamber (319) designed to receive a fluid; a separating element (315) which separates the chamber (319) into a first sub-chamber (319a) and a second sub-chamber (319b); a first fluid connection (320) which is designed to fluidically connect the first sub-chamber (319a) to an outside of the sleeve (314) and which is designed to be connected to a first aspiration-line portion that is to be connected to the fluid pump; a second fluid connection (322) which is designed to fluidically connect the second sub-chamber (319b) to the outside of the sleeve (314) and which is designed to be connected to a second aspiration-line portion that is to be directed to the surgical site; and a backflow preventer which the separating element (315) includes in order to fluidically connect the first sub-chamber (319a) to the second sub-chamber (319b), the backflow preventer being designed to prevent a flow of the fluid from the first sub-chamber (319a) into the second sub-chamber (319b) counter to the suction direction, and the separating element being a flexible separating element (315).

Description

[0001] Fluid reservoir for an aspiration line of a medical system

[0002] The present invention relates to medical systems and, more particularly, to a fluid reservoir for an aspiration line of a medical system.

[0003] There are several surgical techniques for treating, for example, a clouding of the lens of the eye, which in medicine is known as a cataract. The most common technique is phacoemulsification, in which a thin hollow needle attached to a handpiece is inserted into the crystalline lens (Greek: phakos) located in the capsular bag and stimulated to produce ultrasonic vibrations by a drive in the handpiece. A rinsing fluid or irrigation fluid is usually delivered to the surgical site via an irrigation line, and the vibrating hollow needle emulsifies the crystalline lens in its immediate vicinity in such a way that the resulting lens particles, any other particles and fluids, and the irrigation fluid can be suctioned off as aspiration fluid through an aspiration line using an aspiration fluid pump.Once the lens has been completely emulsified and removed, a new artificial lens can be inserted into the now empty capsular bag, allowing a patient treated in this way to regain good vision.

[0004] When the eye lens is fragmented using a hollow needle vibrating at an ultrasonic frequency, it is unavoidable that during a surgical procedure a relatively large lens particle may become lodged in front of the tip of the hollow needle, blocking a suction opening in the hollow needle. This condition is referred to as blockage or occlusion. In such a case, the aspiration fluid pump connected to the aspiration line, which can be a peristaltic pump or a diaphragm pump, for example, builds up a suction pressure in the aspiration line that is several times stronger than in an occlusion-free state, which can assist in breaking the occlusion. In addition, the movement of the hollow needle can apply appropriate energy to the lens particle blocking the hollow needle, shattering it.

[0005] A sudden removal of an occlusion with high suction pressure applied to the aspiration port of the hollow needle can result in not only the aspiration fluid containing the lens particles being drawn into the aspiration line, but also in the inadvertent aspiration of the capsular bag or parts of the iris of a treated eye. Reversing the direction of the aspiration fluid pump, which leads to a backflow (reflux) of the aspiration fluid, can be used as a reflux function to both remove an occlusion caused by a large lens particle and push a suctioned capsular bag or parts of the iris away from the hollow needle, allowing normal suction of the aspiration fluid through the hollow needle to resume.

[0006] Other surgical procedures on the eye of a living being, such as a human or animal, sometimes also require the tissue to be crushed and suctioned away. Examples of such surgical procedures include vitrectomy, in which parts of the vitreous body (Latin: corpus vitreum) are removed, or the entire vitreous body of an eye is removed, for example, to treat the retina. During a vitrectomy, the jelly-like vitreous is crushed using a cutter or vitrectome inserted into the vitreous space, and the resulting vitreous fragments are suctioned away through a suction opening in the vitrectome.To ensure toning or stability of the eye, a fluid, such as balanced salt solution (BSS) followed by a gas or oil, is infused into the eye via an infusion cannula to replace the aspirated vitreous. Occlusion of the vitrectome's suction port can also occur during vitrectomy, which can be resolved by intentionally reversing the flow direction through the vitrectome's suction port.

[0007] Ophthalmic surgical systems used, for example, for phacoemulsification typically include a console having a cassette receiving area, a cassette configured for insertion into the cassette receiving area, an irrigation line, an aspiration line, and a handpiece fluidically connected to the irrigation line and the aspiration line. The handpiece, for example, has a hollow needle for treating an eye to be treated. The cassette typically includes at least part of an irrigation fluid pump, to which the irrigation line is or can be connected, and which serves to deliver an irrigation fluid or treatment fluid to the eye to be treated via the irrigation line, the handpiece, and the hollow needle.The cassette typically further comprises at least part of an aspiration fluid pump, to which the aspiration line is or can be connected, and which serves to suction aspiration fluid from the eye to be treated via the hollow needle, the handpiece, and the aspiration line. The cassette is typically designed to form an interface between the handpiece and the console, and in particular, to prevent the irrigation fluid from coming into contact with driving elements of the irrigation fluid pump and / or console, ensuring sterility during surgery.

[0008] Fig. 14 shows a console 400 of an ophthalmic surgical system with a cassette holder 401. Such a console is shown, for example, in DE 10 2021 111 178 A1.

[0009] In particular, to facilitate consecutive surgical procedures on the eyes of different patients and to ensure appropriate hygiene, a separate and sterile disposable cassette is typically inserted into the console for each patient, and the irrigation and aspiration lines, which are usually provided as a tubing set, are exchanged. This generates large amounts of waste and is time-consuming for consecutive surgical procedures.

[0010] Some ophthalmic surgical systems allow the use of a cassette for multiple patients throughout the day. This type of cassette is called a day cassette. When changing patients, only the irrigation line and the aspiration line are exchanged. Since contaminated aspiration fluid remains in the cassette, particularly in the aspiration fluid pump, after each surgical procedure, a newly connected aspiration line filled with fresh treatment fluid serves as a contamination barrier for the next patient to be treated.However, in order to provide the reflux function even with a daily cassette without contaminating the next patient with aspiration fluid from a previous patient, such ophthalmic surgical systems utilize a near-patient portion of the aspiration line as a reflux volume available for reflux procedures. This volume is typically sufficient to perform multiple reflux procedures. Assuming that contaminated fluid is flushed back for each reflux procedure, the available uncontaminated fluid slowly depletes until the reflux volume is exhausted. To ensure that no further reflux procedures are performed after the reflux volume has been exhausted, the console must monitor the volume of fluid transported during the reflux procedures.An object of the present invention is to provide a device for an ophthalmic surgical system and an ophthalmic surgical system that enable simple multiple use of a cassette for different patients.

[0011] This object is achieved by a fluid reservoir according to claim 1, an aspiration line according to claim 8 and an ophthalmic surgical system according to claim 10.

[0012] The invention provides a fluid reservoir for an aspiration line of a medical system, wherein the aspiration line serves to suction a fluid from a surgical site on a living being by means of a fluid pump of the medical system in a suction direction, comprising a sleeve enclosing a chamber designed to receive a fluid, a separating element separating the chamber into a first sub-chamber and a second sub-chamber, a first fluid port designed to fluidically connect the first sub-chamber to an outside of the sleeve and designed to be connected to a first section of the aspiration line that is to be connected to the fluid pump, a second fluid port designed to fluidically connect the second sub-chamber to the outside of the sleeve and designed to be connected to a second section of the aspiration line that is to be directed towards the surgical site,and a backflow preventer, which the separating element has for fluidically connecting the first sub-chamber to the second sub-chamber, wherein the backflow preventer is designed to prevent a flow of the fluid from the first sub-chamber into the second sub-chamber opposite to the suction direction, and wherein the separating element is a flexible separating element.

[0013] The invention further provides an aspiration line for a medical system, wherein the aspiration line serves to suck a fluid from a surgical site on a living being by means of a fluid pump of the medical system in a suction direction, having a first portion designed to be fluidically connected to the fluid pump and a second portion to be directed toward the surgical site, wherein the aspiration line has a fluid reservoir according to the invention fluidically connected between the first portion and the second portion of the aspiration line.The invention further provides an ophthalmic surgical system for treating an eye of a living being to be treated, comprising a console having a cassette receiving area, a cassette designed to be inserted into the cassette receiving area, an irrigation line, an aspiration line according to the invention, and a handpiece for treating the eye to be treated, wherein the cassette has at least a part of at least one first fluid pump for supplying a fluid via the irrigation line to the eye to be treated and at least a part of at least one second fluid pump for sucking fluid from the eye to be treated via the aspiration line in a suction direction.

[0014] An advantage of the invention is that, for clearing an aspiration line or a hollow needle or similar device of a handpiece fluidically connected to the aspiration line, the fluid reservoir according to the invention, with its movable separating element, provides a large fluid delivery volume of aspiration fluid that can be backflushed against the suction direction. At the same time, the backflow preventer in the fluid reservoir prevents the aspiration fluid of a previous patient from mixing with the aspiration fluid of a current patient. The backflow preventer therefore forms a contamination barrier, which, for example, enables the multiple use of a cassette.

[0015] A further advantage of the invention is that a reflux function of a medical system, in which an aspiration fluid is conveyed by an aspiration fluid pump against the suction direction, can be used for rinsing a handpiece during surgical preparation.

[0016] A further advantage of the invention is that, since the reflux volume is defined by the fluid reservoir according to the invention with the backflow preventer, no reflux limitation is required, which is realized by a control with which a console is provided.

[0017] A further advantage of the invention is that, since the reflux volume per patient does not need to be limited, there is no risk of lines or tubes having to be replaced during surgery due to a lack of available reflux volume. This is the case, for example, if, as mentioned above, part of an aspiration tube is used as reflux volume, but this reflux volume is exceeded during surgery and additional reflux volume can only be provided by replacing the aspiration tube.

[0018] A further advantage of the invention is that the length of an aspiration tube can be selected more freely, since the fluid reservoir provides the reflux volume. This allows for the use of shorter aspiration tubes, which have a lesser impact on the flow behavior in terms of delay effects and flow resistance.

[0019] A further advantage of the invention is that when a cassette is inserted into a receiving area of ​​a console of an ophthalmic surgical system, as shown in Fig. 14, the console does not have to distinguish between a cassette type intended for multiple use, in which a limitation of the reflux volume must usually be carried out, and a cassette type intended for single use, so that the console does not have to have a function for recognizing the cassette type.

[0020] A further advantage of the invention is that with the cassette type for multiple use, the reflux volume no longer needs to be monitored and thus no separate control, for example implemented in the form of firmware, is required.

[0021] The subclaims contain advantageous further developments and improvements of the fluid reservoir specified in claim 1, the aspiration line specified in claim 8 and the ophthalmic surgical system specified in claim 10.

[0022] According to a preferred development of the fluid reservoir of the invention, the flexible separating element is designed in such a way that, upon deformation of the flexible separating element caused by a certain positive pressure difference between the first sub-chamber and the second sub-chamber, a pumping effect of the fluid reservoir in the second sub-chamber is achieved, which enables a certain fluid delivery volume to be conveyed.

[0023] According to a preferred development of the fluid reservoir of the invention, the flexible separating element is designed to be movable between a rest state, which occurs when the pressure in the first sub-chamber and the second sub-chamber is the same, or a permeable state, which occurs when a fluid flows through the chamber at a certain first speed in the suction direction, and a deformed state, which occurs due to the certain positive pressure difference between the first sub-chamber and the second sub-chamber after a certain amount of fluid flows into the first sub-chamber opposite to the suction direction,and to reduce the volume of the second sub-chamber by the determined fluid delivery volume during a movement between the rest state or the permeable state and the deformed state and to increase the volume of the second sub-chamber by the determined fluid delivery volume during a movement between the deformed state and the rest state or the permeable state.

[0024] According to a preferred development of the fluid reservoir of the invention, the specific fluid delivery volume is selected depending on a type of operation on a living being.

[0025] According to a preferred development of the fluid reservoir of the invention, the flexible separating element has a curved initial shape.

[0026] According to a preferred development of the fluid reservoir of the invention, the specific fluid delivery volume is in a range of 1 to 10 ml and in particular 5 ml.

[0027] According to a preferred development of the fluid reservoir of the invention, the backflow preventer is a duckbill valve or a check valve.

[0028] An advantage of this preferred development of the invention is that the fluid reservoir is of simple construction.

[0029] According to a preferred development of the aspiration line of the invention, the first section of the aspiration line has a length such that the fluid reservoir is close to the fluid pump, and in particular a length which lies in a range between 5% and 15% of a total length of the aspiration line.

[0030] An advantage of this preferred development of the invention is that the fluid reservoir does not burden the outer aspiration line near the handpiece or the surgical site, thereby impairing the operator's handling of the handpiece or the outer aspiration line. A further advantage of this preferred development of the invention is that the second section of the aspiration line provides a sufficiently large safety volume in case contaminated aspiration fluid should reach the uncontaminated side of a fluid reservoir due to diffusion or capillary effects or a malfunction of the backflow preventer.

[0031] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. They show:

[0032] Fig. 1 schematically shows a cassette-side arrangement of an ophthalmic surgical system according to the invention;

[0033] Fig. 2 is a sectional view of a fluid reservoir according to a first embodiment of the invention in a first state;

[0034] Fig. 3 is a perspective partial sectional view of the fluid reservoir in Fig. 2

[0035] Fig. 4 is a further sectional view of the fluid reservoir according to the first embodiment of the invention in a second state;

[0036] Fig. 5 is a sectional view of a fluid reservoir according to a first variant of a second embodiment of the invention in a first state;

[0037] Fig. 6 is a perspective partial sectional view of the fluid reservoir in Fig. 5;

[0038] Fig. 7 is an enlarged sectional view of a valve element of the fluid reservoir according to the first variant of the second embodiment of the invention;

[0039] Fig. 8 is an enlarged plan view of a valve plate of the fluid reservoir according to the second embodiment of the invention;

[0040] Fig. 9 is a sectional view of the fluid reservoir according to the first variant of the second embodiment of the invention in a second state;

[0041] Fig. 10 is a perspective partial sectional view of the fluid reservoir in Fig. 9;

[0042] Fig. 11 is a sectional view of the fluid reservoir according to the first variant of the second embodiment of the invention in a third state;

[0043] Fig. 12 is a sectional view of a fluid reservoir according to a second variant of the second embodiment of the invention in a first state;

[0044] Fig. 13 is a sectional view of a fluid reservoir according to the second variant of the second embodiment of the invention in a second state; and Fig. 14 is a console of an ophthalmic surgical system.

[0045] Fig. 1 schematically shows a cassette-side arrangement of an ophthalmic surgical system according to the invention. However, the invention can also be used in other medical systems. The arrangement 102 comprises a cassette 103 with a cassette-side part 104 of an irrigation fluid pump and a cassette-side part 105 of an aspiration fluid pump. The arrangement 102 further comprises an outer irrigation line 106 and an outer aspiration line 107 extending outside the cassette 103, an inner irrigation line 108 and an inner aspiration line 109 extending inside the cassette 103, and a handpiece 110. A first end of the outer irrigation line 106 and a first end of the inner irrigation line 108 are fluidically connected to one another via a first connecting piece 111.A first end of the outer aspiration line 107 and a first end of the inner aspiration line 109 are fluidly connected to each other via a second connector 112. A second end of the inner irrigation line 108 or the inner aspiration line 109 is fluidly connected to the cassette-side part 104 of the irrigation fluid pump or the cassette-side part 105 of the aspiration fluid pump. A second end of the outer irrigation line 106 or the outer aspiration line 107 is each fluidly connected to the handpiece 110. The aspiration line 107 has, between a first part 107a of the outer aspiration line 107 and a second part 107b of the outer aspiration line 107, a fluid reservoir 113 according to the invention, which is suitably fluidically connected to the first part 107a of the aspiration line 107 and the second part 107b of the aspiration line 107b.

[0046] The cassette 103 is, for example, a cassette for insertion into the cassette receptacle 401 of the console 400 of Fig. 14. When such a cassette 103 is inserted into the cassette receptacle 401, the irrigation fluid pump is formed, for example, by the cassette-side part 104 of the irrigation fluid pump and a console-side part of the irrigation fluid pump (not shown and not described in detail). Likewise, the aspiration fluid pump is formed by the cassette-side part 105 of the aspiration fluid pump and a console-side part of the aspiration fluid pump (not shown and not described in detail). In order to avoid contact between fluids transported by the fluid pumps and the driving parts of the fluid pumps when changing cassettes 103, among other things, and to ensure sterility, the driving parts of the fluid pumps are typically located in the console 400.During operation of the ophthalmic surgical system according to the invention during a surgical procedure, for example, the irrigation fluid pump pumps treatment fluid or irrigation fluid from an irrigation fluid container (not shown) via the inner irrigation line.

[0047] 108 and the outer irrigation line 106 are fed to the handpiece 110 and, in the case of the handpiece 110, via, for example, a hollow needle (not shown) or through a space between a needle (not shown) and a sleeve (not shown), to a patient's eye to be operated on. The hollow needle or needle is caused to oscillate in the ultrasonic frequency range, for example, by a piezoelectric drive in the handpiece 110, in order to emulsify the lens of the eye. The lens particles produced during emulsification, possibly other particles and fluids, and the used irrigation fluid are pumped as aspiration fluid by the aspiration fluid pump through, for example, a suction opening in the hollow needle of the handpiece 110 via the outer aspiration line 107, the fluid reservoir 113, and the inner aspiration line.

[0048] 109 and transported to a collecting container for the aspiration fluid, not shown, downstream of the aspiration fluid pump.

[0049] The outer irrigation line 106 and the outer aspiration line 107 are preferably tubes. The outer irrigation line 106, the outer aspiration line 107, and the fluid reservoir 113 preferably form a tube set or hose assembly. The tube set is designed to be interchangeable and fluidically connectable to the handpiece 110 and the first and second connectors 111 and 112. In a medical system, the fluid reservoir 113 is preferably arranged near the cassette 103 or near the aspiration fluid pump, respectively, and the lengths of the first part 107a of the outer aspiration line 107 and the second part 107b of the outer aspiration line 107 are selected accordingly.

[0050] 2 and 3 show a sectional view and a perspective partial sectional view of a fluid reservoir 213 according to a first embodiment of the invention in a first state. The fluid reservoir 213 has a radially symmetrical housing 214 and a radially symmetrical flexible separating element 215. The housing 214 has, along a longitudinal axis 216 of the fluid reservoir 213, a first shell-shaped housing part 217 and a second shell-shaped housing part 218, which enclose a chamber 219 of the fluid reservoir 213 on their inner side. The flexible separating element 215 divides the chamber 219 into a first sub-chamber 219a, which is defined by the first shell-shaped housing part 217 and the flexible separating element 215, and a second sub-chamber 219b, which is defined by the second shell-shaped housing part 218 and the flexible separating element 215.The first shell-shaped housing part 217 has, along the longitudinal axis 216 at a first end thereof, a first fluid connection 220 on the aspiration fluid pump side for connection to, for example, the first part 107a of the outer aspiration line 107 shown in Fig. 1. The first fluid connection 220 is cylindrical and has a circular first opening 221 that penetrates the first housing part 217 and fluidically connects the first sub-chamber 219a to the outside of the housing 214. The second shell-shaped housing part 218 has, along the longitudinal axis 216 at a first end thereof, a second fluid connection 222 on the handpiece side for connection to, for example, the second part 107b of the outer aspiration line 107 shown in Fig. 1.The second fluid connection 222 is cylindrical and has a circular second opening 223 which penetrates the second housing part 218 and fluidically connects the second sub-chamber 219b to the outside of the housing 214.

[0051] The first shell-shaped housing part 217 has, along the longitudinal axis 216 at a second end thereof, a radial edge section which has a peripherally extending first groove 224. The second shell-shaped housing part 218 also has, along the longitudinal axis 216 at a second end thereof, a radial edge section which has a peripherally extending second groove 225. The first and second grooves 224 and 225 lie opposite one another and together form an annular cavity. The cavity lies in a plane that is perpendicular to the longitudinal axis 216 and forms a boundary plane between the first and second shell-shaped housing parts 217 and 218, and circumscribes the longitudinal axis 216 in this plane. The first and second grooves 224 and 225 are each delimited in the radial direction by an outer wall 226 and an inner wall 1 of the respective radial edge section.The outer walls 226 of the first and second grooves 224 and 225 have a length along the longitudinal axis 216 such that they touch each other at an abutment region 228, while the inner walls 1 have a length along the longitudinal axis 216 which is shorter than the length of the outer walls 226, such that a gap 229 is formed between the inner walls 1 along the longitudinal axis 216.

[0052] The flexible separating element 215 has a hollowed or curved shape on the side facing the second opening 223. The flexible separating element 215 has a T-shaped bead 230 in a radial edge section, which transitions radially inward into a radially symmetrical, approximately frustoconical region 231, which is adjoined further radially inward by a beak-shaped region 232. The beak-shaped region 232 has a first wall 233 and a second wall 234, which taper toward each other in a concave manner radially inward and end in sealing lips 236, which delimit a slot-shaped opening 237 that can be closed and opened by the sealing lips 236. The beak-shaped region 232 thus forms a beak valve.

[0053] 2 and 3, an unloaded state or rest state of the duckbill valve or the flexible separating element 215 is shown therein, in which an equal pressure exists on both sides of the flexible separating element 215, that is to say in the first sub-chamber 219a and the second sub-chamber 219b, and in which the flexible separating element 215 is thus not deformed and has its initial state.

[0054] The sealing lips 236 are preferably designed and / or the material of the flexible separating element 215 and / or its dimensions are preferably selected such that the sealing lips 236, in the resting state, close the slot-shaped opening 237 in Fig. 3 in a fluid-tight manner and only open when a fluid flows in a passage direction 238. This prevents fluid exchange between the first subchamber 219a and the second subchamber 219b, even in a stationary state of a medical system in which no fluids are flowing, and contamination of, for example, aspiration fluid in the second subchamber 219b by aspiration fluid in the first subchamber 219a can be avoided.

[0055] The rest state shown in Figs. 2 and 3 in the first embodiment shown is, due to properties of the separating element 215, preferably similar to a flow state of the duckbill valve or the flexible separating element 215, in which a fluid flows relatively stably, i.e., at a constant velocity, and without exceeding a critical flow velocity in a flow direction 238 through the housing 214, and the separating element 215 is deformed only slightly further in the direction of the first opening 221 compared to the rest state in Fig. 2. The critical flow velocity is, for example, a velocity at which the beak-shaped region 232 begins to oscillate strongly and the oscillation is transmitted to the separating element 215.In the passage state of the duckbill valve, a fluid, in particular an aspiration fluid, flows in the passage direction 238 through the second and first openings 223 and 221 of the fluid reservoir 213, for example from the handpiece 110 shown in Fig. 1 to the cassette 103 also shown there. The fluid and at a certain pressure of the fluid push the sealing lips 236 apart and the slit-shaped opening 237 allows the fluid to flow through.

[0056] Fig. 4 shows a further sectional view of the fluid reservoir 213 according to the first embodiment of the invention in a second state. This shows a blocking state of the duckbill valve or a deformed state of the flexible separating element 215, which occurs when a fluid flows in a blocking direction 239 into the housing 214 or the first subchamber 219a or, more generally, when the pressure in the first subchamber 219a is greater than the pressure in the second subchamber 219b, i.e., a positive pressure difference exists between the first and second subchambers 219a and 219b. The flexible separating element 215 is deformed in the direction of the second opening 223, wherein due to a contact pressure of the sealing lips 236 against each other caused by the deformation, the sealing lips 236 close the slot-shaped opening 237 in such a way that no fluid can enter the second sub-chamber 219b of the housing 214.Thus, for example, in an ophthalmic surgical system, no contaminated aspiration fluid flows in the blocking direction 239, that is, for example, in a direction from the cassette 103 shown in Fig. 1 to the handpiece 110 also shown there, through the slot-shaped opening 237.

[0057] The flexible separating element 215 is preferably a membrane. The membrane is made of silicone, for example, while the shell-shaped first and second housing parts 217 and 218 are made of polycarbonate (PC), polypropylene (PP), or acrylonitrile-butadiene-styrene copolymer (ABS), for example, by injection molding. The thickness of the walls of the first and second housing parts 217 and 218 and their material are selected such that the first and second housing parts 217 and 218 are dimensionally stable or rigid compared to the flexible separating element 215. The thickness of the walls is, for example, 0.5 mm. In Fig. 2, the flexible separating element 215 is preferably clamped or pressed between the first and second shell-shaped housing parts 217 and 218 by means of the T-shaped bead 230, which is arranged in the first and second grooves 224 and 225.The first and second shell-shaped housing parts 217 and 218 are joined to one another at the abutment area 228 or in the vicinity of the abutment area 228 by welding, gluing, screwing, etc. Figs. 5 and 6 show a sectional view and a perspective partial sectional view of a fluid reservoir 313 according to a first variant of a second embodiment of the invention in a first state. The fluid reservoir 313 has a radially symmetrical housing 314 and a radially symmetrical flexible separating element 315. The housing 314 has, along a longitudinal axis 316 of the fluid reservoir 313, a first shell-shaped housing part 317 and a second shell-shaped housing part 318, which enclose a chamber 319 of the fluid reservoir 313 on their inner side.The flexible separating element 315 divides the chamber 319 into a first sub-chamber 319a, which is defined by the first shell-shaped housing part 317 and the flexible separating element 315, and a second sub-chamber 319b, which is defined by the second shell-shaped housing part 318 and the flexible separating element 315. The first shell-shaped housing part 317 has, along the longitudinal axis 316 at a first end thereof, a first fluid connection 320 on the aspiration fluid pump side for connection to, for example, the first part 107a of the outer aspiration line 107 shown in Fig. 1. The first fluid connection 320 is cylindrical and has a circular first opening 321 perpendicular to the longitudinal axis 316, which penetrates the first housing part 317 along the longitudinal axis 316 and fluidically connects the first sub-chamber 319a to the outside of the housing 314.The second shell-shaped housing part 318 has, along the longitudinal axis 316 at a first end thereof, a handpiece-side second fluid connection 322 for connection to, for example, the second part 107b of the outer aspiration line 107 shown in Fig. 1. The second fluid connection 322 is cylindrical and has a circular second opening 323 perpendicular to the longitudinal axis 316, which penetrates the second housing part 318 along the longitudinal axis 316 and fluidically connects the second sub-chamber 319b to the outside of the housing 314.

[0058] The first shell-shaped housing part 317 has, along the longitudinal axis 316 at a second end thereof, a radial edge section which has a peripherally extending first groove 324. The second shell-shaped housing part 318 also has, along the longitudinal axis 316 at a second end thereof, a radial edge section which has a peripherally extending second groove 325. The first and second grooves 324 and 325 lie opposite one another and together form an annular cavity. The cavity lies in a plane that is perpendicular to the longitudinal axis 316 and forms a boundary plane between the first and second shell-shaped housing parts 317 and 318, and circumscribes the longitudinal axis 316 in this plane. The first and second grooves 324 and 325 are each delimited in the radial direction by an outer wall 326 and an inner wall 327 of the respective radial edge section.The outer walls 326 of the first and second grooves 324 and 325 have a length along the longitudinal axis 316 such that they touch each other at an abutment region 328, while the inner walls 327 have a length along the longitudinal axis 316 which is shorter than the length of the outer walls 326, such that a gap 329 is formed between the inner walls 327 along the longitudinal axis 316.

[0059] The flexible separating element 315 has a hollowed or curved shape on the side facing the second opening 323. The flexible separating element 315 has a T-shaped bead 330 in a radial edge section, which transitions radially inward into a radially symmetrical S-shaped region 340, which is further radially inwardly adjoined by a circular opening 341 perpendicular to the longitudinal axis 316. A circular valve plate 342, which forms a valve seat of a check valve, is inserted into the circular opening 341. The circular valve plate 342 has a circular opening 343 therein. A valve stem 344 of a radially symmetrical valve element 345, which has the valve stem 344 and a valve head 346, is arranged in the circular opening 343. The valve head 346 serves as a valve closure.

[0060] Fig. 7 shows an enlarged sectional view of the valve element 345 of the fluid reservoir 313 according to the first variant of the second embodiment of the invention. The valve stem 344 has, along the longitudinal axis 316 towards the circular opening 343 of the valve plate 342 in Fig. 5, initially a cylindrical first section 347 with a radial diameter constant perpendicular to the longitudinal axis 316, a bead-shaped second section 348 with a radial diameter that initially increases slowly along the longitudinal axis 316 and then decreases sharply, a cylindrical third section 349 with a radial diameter constant perpendicular to the longitudinal axis 316, and an umbrella-shaped section that forms the valve head 346. With a valve element 345 inserted into the valve plate 342, as shown in Fig.5, the cylindrical third portion 349 of the valve element 345 is arranged in the circular opening 343 of the valve plate 342. The cylindrical third portion 349 is preferably designed such that it at least partially fluid-tightly occupies the circular opening 343 of the valve plate 342.

[0061] Fig. 8 shows an enlarged top view of the circular valve plate 342 of the fluid reservoir 313 according to the second embodiment of the invention. In addition to the circular opening 343, the circular valve plate 342 has a first annular portion 350 surrounding the circular opening 343, four spokes 351 extending radially from the first annular portion 350, and a second annular portion 352 in which the spokes 351 terminate. Between the spokes 351, four recesses 353 are formed in the valve plate 342 in the polar direction, which are suitable for allowing a fluid to pass through.

[0062] Referring back to Figs. 5 and 6, an unloaded or resting state of the check valve or the flexible separating element 315 is shown, in which an equal pressure exists on both sides of the flexible separating element 315, i.e., in the first sub-chamber 319a and the second sub-chamber 319b, and in which the flexible separating element 315 is thus not deformed and has its initial state. In the resting state, no fluid, in particular aspiration fluid, flows through the valve plate 342 in the flexible separating element 315.

[0063] 9 and 10 show a sectional view and a perspective partial sectional view of the fluid reservoir 313 according to the first variant of the second embodiment of the invention in a second state. These show a passage state of the check valve or the flexible separating element 315, in which a fluid, in particular an aspiration fluid, flows through the second and first openings 323 and 321 of the fluid reservoir 313 relatively stably, i.e., at a constant velocity, and without exceeding a critical flow velocity through the second opening 323 and the first opening 321 in a passage direction 338, for example, from the handpiece 110 shown in Fig. 1 to the cassette 103 also shown there. The critical flow velocity is, for example, a velocity at which the valve head 346 begins to vibrate or flutter strongly, and the vibration is transmitted to the separating element 315.In comparison to the rest state in Figs. 5 and 6, the separating element 315 is preferably deformed only slightly further in the direction of the first opening 321 in the pass-through state.

[0064] In the first variant of the second embodiment of the

[0065] According to the invention, on the one hand, the dimensions of the valve head 346, for example a thickness profile of the valve head 346 depending on the radial direction in the section of Fig. 7, and / or the material of at least the valve head 346 are selected such that in the rest state of the check valve or the flexible separating element 315 shown in Fig. 5 and 6, a radially outer region 354 of the valve head 346 presses in a blocking direction 339 against the second annular section 352 shown in Fig. 8 with a restoring force such that the recesses 353 of the valve plate 342 are fluid-tightly closed off from the first sub-chamber 319a and no fluid can enter the second sub-chamber 319b of the housing 314. As a result, a fluid exchange between the first sub-chamber 319a and the second sub-chamber 319b in Fig.5 can be prevented, and contamination of, for example, aspiration fluid in the second sub-chamber 319b by aspiration fluid in the first sub-chamber 319a can be avoided. If the longitudinal axis 316 of the fluid reservoir 313 is further aligned parallel to the acceleration due to gravity, at least the radially outer region 354 of the valve head 346 shown in Fig. 7 presses in the blocking direction 339 against the second annular section 352 shown in Fig. 8 or rests thereon due to the gravity of the valve element 345, and the recesses 353 of the valve plate 342 are, with a suitable design of the valve element 345, fluid-tightly closed with respect to the first sub-chamber 319a in the rest state, such that no fluid can enter the second sub-chamber 319b of the housing 314.

[0066] 5, 6, 9 and 10, the dimensions of the valve head 346 and / or the material of at least the valve head 346 are selected such that in the passage state shown in Fig. 9, in which a fluid flows in the passage direction 338 from the second opening 323 to the first opening 321 under a certain minimum pressure, the radially outer region 354 in Fig. 7 of the valve head 346 bends elastically away from the valve plate 342 against the restoring force and possibly the force of gravity, such that the radially outer region 354 is sufficiently removed from the valve plate 342 at a certain distance 355 to open the check valve or to enable a suitable flow of fluid through at least the recesses 353 towards the first opening 321.

[0067] Fig. 11 shows a sectional view of the fluid reservoir according to the first variant of the second embodiment of the invention in a third state. This shows a blocking state of the check valve, in which the flexible separating element 315 has a deformed state that occurs when a fluid flows in the blocking direction 339 into the housing 314 or the first sub-chamber 319a, or more generally, when the pressure in the first sub-chamber 319a is greater than the pressure in the second sub-chamber 319b, i.e., a positive pressure difference exists between the first and second sub-chambers 319a and 319b. The flexible separating element 315 is deformed in the direction of the second opening 323. In addition, the valve head 346 of the valve element 345 and in particular its radially outer region 354 in Fig. 7 is pressed even more tightly against the valve plate 342 than in the rest state, such that no fluid can enter the second sub-chamber 319b of the housing 314.Thus, contamination of, for example, aspiration fluid in the second sub-chamber 319b by aspiration fluid in the first sub-chamber 319a can be avoided.

[0068] Figs. 12 and 13 show sectional views of a fluid reservoir 313 according to a second variant of the second embodiment of the invention in a first and a second state. In this variant, the valve head 346, slightly modified compared to Fig. 7, has a flat, round-head shape with a round side along the longitudinal direction 316 and a flat side facing the valve plate 342. In this variant, at least the length of the cylindrical third section 349 of the valve element 345 shown in Fig. 7 along the longitudinal axis 316 is selected such that the valve element 345 can move to such an extent that the valve head 346, in a first state or passage state of the check valve shown in Fig. 12, is sufficiently removed from the valve plate 342 at a certain distance 355 along the longitudinal axis 316 to enable a suitable flow of the fluid through at least the recesses 353 of the valve plate 342.The bead-shaped second portion 348 of the valve stem 344 presses against the first annular portion 350 of the valve plate 342 shown in Fig. 8, such that further movement of the valve stem 344 is prevented.

[0069] In a second or blocked state of the check valve shown in Fig. 13, the flexible separating element 315 can be seen in a deformed state, which occurs when a fluid flows in the blocked direction 339 into the housing 314 or the first sub-chamber 319a or, more generally, when the pressure in the first sub-chamber 319a is greater than the pressure in the second sub-chamber 319b, i.e., a positive pressure difference exists between the first and second sub-chambers 319a and 319b. The valve head 346 of the valve element 345 is pressed more strongly against the valve plate 342 in a closing manner than in a resting state in which only gravity acts on the valve element 345. It should be noted that in the second variant of the second embodiment of the invention, for the check valve to be closed in the resting state, the longitudinal axis 316 must be aligned with the direction of gravity.The valve element 345 is therefore preferably designed and its material is selected such that, both in the resting state and in the blocking state, no fluid can pass through the recesses 353 and the circular opening 343 in the valve plate 342 in Fig. 8 into the second subchamber 319b of the housing 314. Thus, contamination of, for example, aspiration fluid in the second subchamber 319b by aspiration fluid in the first subchamber 319a can be avoided.

[0070] The flexible separating element 315 is preferably a flexible membrane. The membrane is made of silicone, for example, while the shell-shaped housing parts 317 and 318 are made of polycarbonate (PC), polypropylene (PP), or acrylonitrile-butadiene-styrene copolymer (ABS), for example, by injection molding. The thickness of the walls of the first and second housing parts 317 and 318 and their material are selected such that the first and second housing parts 317 and 318 are dimensionally stable or rigid compared to the flexible separating element 315. The thickness of the walls is, for example, 0.5 mm. The membrane is preferably clamped or pressed between the first and second shell-shaped housing parts 317 and 318 with the T-shaped bead 330 in Fig. 5, which is arranged in the first and second grooves 324 and 325.The first and second shell-shaped housing parts 317 and 318 are joined to one another at the abutment area 328 or in the vicinity of the abutment area 328 by welding, gluing, screwing, etc. The valve plate 342 is preferably made of hard plastic and is preferably joined to the flexible separating element 315 by means of injection molding, gluing, or welding via a step 356 shown in Figs. 8 and 12, which is formed in the second annular section 352 on a side of the valve plate 342 shown in Fig. 8 facing away from the valve head 346.

[0071] When operating a console of an ophthalmic surgical system, such as console 400 in Fig. 14, a cassette, such as cassette 103 in Fig. 1, is inserted into cassette receptacle 401. The cassette is intended to be used for multiple patients to be treated, for example, over the course of a day. The exemplary tubing set in the invention, as shown in Fig. 1, has, for example, the outer irrigation line 106 and the outer aspiration line 107 with the fluid reservoir 113, wherein the lines 106 and 107 are designed as tubes. Before a tubing set is used for the first time, the aspiration line 107 and the fluid reservoir 113 are typically completely prefilled (primed) with an irrigation fluid or treatment fluid, such as a balanced salt solution (BSS), so that no air bubbles are present in the aspiration path.During an operation with the handpiece 110, the aspiration fluid, drawn in by the aspiration fluid pump, flows in a suction direction through the aspiration line 107 and the fluid reservoir 113 toward the cassette 103. If the tubing set has the fluid reservoir 213 shown in Figs. 2-4, the aspiration fluid flows in the flow direction 238 shown in Fig. 2, which is a flow direction of the duckbill valve shown therein. Alternatively, if the tubing set has the fluid reservoir 313 shown in Figs. 5, 6, and 9-13, the aspiration fluid flows in the flow direction 338 shown in Figs. 9 and 12, which is a flow direction of the check valve shown therein. Under these conditions, the flexible separating element 215 or 315 assumes a permeable state in both the fluid reservoir 213 and the fluid reservoir 313.

[0072] If the flow direction of the aspiration fluid is reversed during the operation, for example if a reflux function of the console 400 is activated by a control of the console 400 (not shown) in Fig. 12, for example to eliminate an occlusion of a hollow needle of the handpiece 102 in Fig. 1 by a large lens particle and / or to push a sucked capsular bag or sucked parts of an iris away from the hollow needle, aspiration fluid from the aspiration fluid pump side flows, driven by the aspiration fluid pump, away from the cassette 103 and through the first part 107a of the outer aspiration line 107 into the fluid reservoir 113. If the tubing set has the fluid reservoir 213 shown in Figs. 2-4, the aspiration fluid flows in the blocking direction 239 shown in Figs. 2 and 4, which is a blocking direction of the duckbill valve shown therein. However, if the hose set is as shown in Fig.5, 6, and 9-13, the aspiration fluid flows in the blocking direction 339 shown in FIGS. 5, 11, and 13, which is a blocking direction of the check valve shown therein. Under these conditions, the flexible separating element 215 or 315 in both the fluid reservoir 213 and the fluid reservoir 313 assumes a deformed state, as shown in FIGS. 4, 11, and 13.

[0073] When changing from the resting state or permeable state to the blocking state or deformed state of the flexible separating element 215 or 315, the duckbill valve or the check valve begins to block, and the aspiration fluid flowing inversely into the first sub-chamber 219a or 319a of the fluid reservoir 213 or 313 presses via the separating element 215 or 315 only aspiration fluid to the handpiece 110 in Fig. 1, which is located in the second sub-chamber 219b or 319b of the respective fluid reservoir 213 or 313 and the second part 107b of the outer aspiration line 107 shown in Fig. 1. The flexible separating element 215 or 315 acts together with the aspiration fluid on the aspiration fluid pump side pressing against the flexible separating element 215 or 315 in the blocking direction 239 or 339 in the first sub-chamber 219a or 319a like a diaphragm pump, which pumps the handpiece-side aspiration fluid into the second sub-chamber 219b or319b in the direction of the handpiece 110.

[0074] As an extension of the invention, a control of the console 400 in Fig. 14 controls the aspiration fluid pump such that the aspiration fluid pump preferably only conveys aspiration fluid counter to the flow direction of the fluid reservoir 213 or 313 until the aspiration fluid contained in the second subchamber 219b or 319b has been completely emptied from the second subchamber 219b or 319b. This provides an additional safety measure to prevent unwanted contamination.

[0075] If the flow direction is subsequently changed back to the suction direction or passage direction 238, 338 during the operation, the duckbill valve in Fig. 2 or the check valve in Fig. 9 and 12 opens, the separating element 215 or 315 is returned to the passage state by the aspiration fluid and its restoring force, the fluid reservoir 113, 213, 313 fills with an aspiration fluid of a current patient, and the aspiration fluid can flow in the passage direction 238 or 338 towards the cassette 103.

[0076] When changing between patients, it is necessary to clean or replace the handpiece 110 in Fig. 1. In addition, at least the second part 107b of the outer aspiration line 107 and the reservoir 113, 213, 313 must be replaced. Typically, however, the entire outer aspiration line 107 and the fluid reservoir 113, 213, 313 as well as the outer irrigation line 106 are replaced. When changing between patients, the second part 107b of the outer aspiration line 107 and the second sub-chamber 219b or 319b of the respective fluid reservoir 213 or 313 in, for example, Fig. 2, 5 or Fig. 12 are filled with uncontaminated aspiration fluid or aspiration fluid of the new patient. This ensures that when the reflux function of the console 400 is activated, no fluid from a previous patient flows through the second sub-chamber 219b or 319b of the fluid reservoir 213 or 313 in Fig. 2, 5 or Fig.12 and the second part 107b of the outer aspiration line 107 in Fig. 1, but rather only the aspirated aspiration fluid of a current patient is pumped from the respective reservoir 113, 213, 313 back toward an eye to be treated. The duckbill valve or the check valve, together with the flexible separating element 215 or 315, forms the barrier between the aspiration fluid of a previous patient and the aspiration fluid of a current patient.

[0077] The volume displaced by the flexible separating element 215 or 315 between the resting state or permeable state and the blocking state in the second sub-chamber 219b or 319b of the respective fluid reservoir 213 or 313 in Fig. 2, 5, or Fig. 12, respectively, is referred to herein as the fluid delivery volume. In order to adjust the fluid delivery volume displaced between the resting state or permeable state and the blocking state in the second sub-chamber 219b or 319b of the respective fluid reservoir 213 or 313 in, for example, Fig. 2, 5, or 12, the chamber 219 or 319 has a predetermined shape and a predetermined volume, and the flexible separating element 215 or 315 has a predetermined initial shape. Due to the hollowed or curved initial shape of the flexible separating element 215 or 315, as shown for example in Figs. 2, 5 and 12, the second partial chamber 219b or 319b takes up a substantial part of the volume of the chamber 219 or 319b in the rest state or the pass-through state.319 in order to make the fluid delivery volume and thus also the volume for reflux processes as large as possible and to optimally use the volume of the chamber 219 or 319 for providing the fluid delivery volume.

[0078] The fluid reservoir 113 in Fig. 1 is preferably located as close as possible to the cassette 103. This has the advantage that the fluid reservoir 113 does not weigh down the outer aspiration line 107 in the vicinity of the handpiece 110 and thus does not impair the handling of the handpiece 110 by an operator. The outer aspiration line 107 in ophthalmic surgical systems usually has a length of approximately 2 m and a volume of 2 ml to 4 ml and preferably 3.5 ml. The second sub-chamber 219b or 319b of the respective fluid reservoir 213 or 313 in Fig. 2 and 5 in an ophthalmic surgical system of the invention in the initial state of the flexible separating element 215 or 315 preferably has a volume in a range of 1 ml to 10 ml and preferably 5 ml. This volume corresponds approximately to the fluid delivery volume and is sufficient, for example, to fill the aspiration line 107 orto free a hollow needle of the handpiece 110 from a blockage using a backflushed aspiration fluid. The volume provided by a fluid reservoir 113 according to the invention in Fig. 1, in addition to the first part 107a of the outer aspiration line 107, significantly increases the available reflux volume and improves the control flexibility of the aspiration fluid pump. The first part 107a of the outer aspiration line 107 provides a safety volume in case contaminated aspiration fluid should reach the uncontaminated side of a fluid reservoir 113 due to diffusion or capillary effects and / or a defect in the duckbill valve or check valve.

[0079] The spring constant or elastic modulus of the flexible separating element 215 or 315, for example, in Figs. 2, 5, and 12, is low and suitably selected to preferably guarantee both sufficient dimensional stability in the initial state and a not excessively high restoring force in the deformed state of the flexible separating element 215 or 315. A lower restoring force is associated with easier deformability and better separating element movement, i.e., a lower pressure loss. The flexible separating element 215 or 315 in Figs. 2, 5, and 12 can be made of thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), or ethylene propylene diene rubber (EPDM), in addition to silicone.

[0080] Although the present invention has been described above with reference to preferred embodiments, it is not limited thereto but can be modified in many ways.

[0081] The fluid reservoir and aspiration line described herein can be used in any surgical or medical system in which fluid, with or without tissue parts, is to be aspirated with a handpiece, instrument, or without a handpiece or instrument. In addition to eye surgery or ophthalmic surgery systems, such as systems for vitrectomy, such systems include neurosurgical, visceral surgery, oral surgery, and other surgical or non-surgical medical systems in these fields. In ophthalmic surgery systems for vitrectomy, the aspiration line 17 shown in Figure 1 is typically fluidically connected to a vitrectome, while the irrigation line, as an infusion line, is fluidically connected to an infusion cannula. In variations of the invention, the first and second housing parts have a different shape, such as a cuboid or cylindrical shape.Instead of a housing, the reservoir in variations of the invention is another shell, such as a tubular shell. In variations of the invention, the flexible separating element is, as an alternative to a membrane, another flexible element with thin walls, such as a flexible film. In such cases, the resting state and the permeable state can differ significantly. In variations of the invention, the flexible separating element has a flat or concave shape. The bead 230 or 330 in, for example, Figs. 2, 5, and 12, in variations of the invention, has a circular or oval cross-section.

[0082] In other medical systems, the outer aspiration line 107a has a suitable length and volume. In another medical system, the second subchamber 219b or 319b of the respective fluid reservoir 213 or 313 in Fig. 2, 5, or 12 has a correspondingly suitable volume in the initial state of the flexible separating element 215 or 315. This volume is sufficient, for example, to repeatedly clear the aspiration line 107 or a hollow needle of the handpiece 110 of a blockage using a backflushed aspiration fluid.

[0083] List of reference symbols

[0084] 102 Arrangement

[0085] 103 cassette

[0086] 104 cassette-side part of the irrigation fluid pump

[0087] 105 cassette-side part of the aspiration fluid pump

[0088] 106 external irrigation line

[0089] 107 external aspiration line

[0090] 107a first part of the external aspiration line

[0091] 107b second part of the external aspiration line

[0092] 108 internal irrigation line

[0093] 109 internal aspiration line

[0094] 1 10 Handpiece

[0095] 1 1 1 first connecting piece

[0096] 1 12 second connecting piece

[0097] 1 13, 213, 313 Fluid reservoir

[0098] 214, 314 housing

[0099] 215, 315 separator

[0100] 216, 316 longitudinal axis

[0101] 217, 317 first housing part

[0102] 218, 318 second housing part

[0103] 219, 319 Chamber

[0104] 219a, 319a first subchamber

[0105] 219b, 319b second subchamber

[0106] 220, 320 first fluid connection

[0107] 221 , 321 first opening

[0108] 222, 322 second fluid connection

[0109] 223, 323 second opening

[0110] 224, 324 first groove

[0111] 225, 325 second groove

[0112] 226, 326 exterior wall

[0113] 227, 327 interior wall

[0114] 228, 328 kick-off area

[0115] 229, 329 gap, 330 bead frustoconical area beak-shaped area first wall second wall

[0116] Sealing lips slit-shaped opening , 338 passage direction , 339 blocking direction S-shaped area circular opening valve plate circular opening valve stem valve element valve head cylindrical first section bead-shaped second section cylindrical third section first annular section spoke second annular section recesses radial outer area distance step console cassette holder

Claims

TI Patent claims 1 . A fluid reservoir (113; 213; 313) for an aspiration line (107) of a medical system, wherein the aspiration line (107) serves to suck a fluid from a surgical site on a living being by means of a fluid pump of the medical system in a suction direction (238; 338), comprising: - a shell (214; 314) enclosing a chamber (219; 319) designed to contain a fluid; - a separating element (215; 315) which separates the chamber (219; 319) into a first sub-chamber (219a; 319a) and a second sub-chamber (219b; 319b); - a first fluid connection (220; 320) designed to fluidically connect the first sub-chamber (219a; 319a) to an outer side of the shell (214; 314) and designed to be connected to a first portion (107a) of the aspiration line (107) to be connected to the fluid pump; - a second fluid port (222; 322) designed to fluidically connect the second sub-chamber (219b; 319b) to the outside of the sheath (214; 314) and designed to be connected to a second portion (107b) of the aspiration line (107) to be directed toward the surgical site; and - a backflow preventer, which the separating element (215; 315) has, in order to fluidically connect the first sub-chamber (219a; 319a) to the second sub-chamber (219b; 319b), wherein the backflow preventer is designed to prevent a flow of the fluid from the first sub-chamber (219a; 319a) into the second sub-chamber (219b, 319b) opposite to the suction direction (238; 338), and wherein the separating element is a flexible separating element (215; 315).

2. Fluid reservoir (113; 213; 313) according to claim 1, characterized in that the flexible separating element (215; 315) is designed in such a way that, upon deformation of the flexible separating element (215; 315) caused by a certain positive pressure difference between the first sub-chamber (219a; 319a) and the second sub-chamber (219b; 319b), a pumping effect of the fluid reservoir (113; 213; 313) in the second sub-chamber (219b; 319b) is achieved, which enables a certain fluid delivery volume to be conveyed.

3. Fluid reservoir (113; 213; 313) according to claim 1 or 2, characterized in that the flexible separating element (215; 315) is designed in such a way that it can switch between a rest state, which occurs when the pressure in the first sub-chamber (219a; 319a) and the second sub-chamber (219b; 319b) is the same, or a permeable state, which occurs when a fluid flows through the chamber (219; 319) at a certain first speed in the suction direction (238; 338), and a deformed state, which occurs due to the certain positive pressure difference between the first sub-chamber (219a; 319a) and the second sub-chamber (219b; 319b) after a certain amount of fluid flows into the first sub-chamber (219a; 319a) opposite to the suction direction (238; 338). 319a) to be movable, and to adjust the volume of the second sub-chamber (219b;319b) to reduce the specific fluid delivery volume and, during a movement between the deformed state and the rest state or the passage state, to increase the volume of the second sub-chamber (219b, 319b) by the specific fluid delivery volume; 4. Fluid reservoir (113; 213; 313) according to claim 1, 2 or 3, characterized in that the specific fluid delivery volume is selected depending on a type of operation on a living being.

5. Fluid reservoir (213, 313) according to one of the preceding claims, characterized in that the flexible separating element (215; 315) has a curved initial shape.

6. Fluid reservoir (113; 213; 313) according to one of claims 2 to 5, characterized in that the determined fluid delivery volume is in a range of 1 to 10 ml and is in particular 5 ml.

7. Fluid reservoir (213; 313) according to one of the preceding claims, characterized in that the backflow preventer is a duckbill valve or a check valve.

8. Aspiration line (107) for a medical system, wherein the aspiration line (107) serves to suck a fluid from a surgical site on a living being by means of a fluid pump of the medical system in a suction direction (238; 338), comprising: - a first portion (107a) designed to be fluidly connected to the fluid pump, and - a second section (107b) to be directed towards the surgical site, characterized in that the aspiration line (107) comprises a fluid reservoir (113; 213; 313) according to one of the preceding claims, which is fluidically connected between the first section (107a) and the second section (107b) of the aspiration line (107).

9. Aspiration line (107) according to claim 7, characterized in that the first section (107a) of the aspiration line (107) has a length such that the fluid reservoir (113) is close to the fluid pump, and in particular has a length which lies in a range between 5% to 15% of a total length of the aspiration line (107).

10. An ophthalmic surgical system for treating an eye of a living being, comprising: - a console (400) having a cassette receiving area (401); - a cassette (103) designed to be inserted into the cassette receiving area (401); - an irrigation line (106); - an aspiration line (107); and - a handpiece (110) for treating the eye to be treated, wherein the cassette (103) comprises at least a part (104) of at least one first fluid pump for supplying a fluid via the irrigation line (106) to the eye to be treated and at least a part (105) of at least one second fluid pump for sucking fluid from the eye to be treated via the aspiration line (107) in a suction direction (238; 338), characterized by an aspiration line (107) according to claim 8 or 9.

Images