Preventing vacuum oscillations in Venturi surgical systems

Abstract

A control method for generating a substantially oscillation-free venturi vacuum for a surgical system generally involves utilizing real-time readings from a venturi vacuum generator inlet pressure transducer and a vacuum pressure transducer on the vacuum side of the venturi vacuum generator. These readings can be employed to identify areas of oscillation on the vacuum side in real time, which can then be addressed by a bleed-control proportional valve. When used in combination with a throttling-control proportional valve on the inlet side of the venturi vacuum generator, the pressures can be manipulated individually in relation to each other and / or as directed through a central controller. In this manner, the presence of vacuum-side oscillations can be avoided to provide a more stable vacuum-assisted surgery.

Description

[Technical field]

[0001] Claiming priority This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 960,777, entitled "VACUUM OSCILLATION PREVENTION IN A VENTURI SURGICAL SYSTEM," filed on January 14, 2020, by inventor Jiansheng Zhou, which is hereby incorporated by reference in its entirety as if fully and completely set forth herein. [Background technology]

[0002] Over the years, many dramatic advances have occurred in the field of minimally invasive surgery. Whether the procedure is placing a vascular stent or performing eye surgery, smaller, more precise instruments and improved techniques are now readily available. A common aspect of many minimally invasive surgeries is the use of suction during the procedure. In these minimally invasive surgeries, suction is necessary to remove fluids, tissue, or other materials. For example, in eye surgery to address retinal diseases, it is common to use suction as part of a vitrectomy.

[0003] A vitrectomy is the removal of some or all of the vitreous humor from a patient's eye. In some cases, a vitrectomy may constitute the majority of the surgery. A vitrectomy may also accompany cataract surgery, retinal repair surgery, surgery to address macular fold formation, or a number of other conditions.

[0004] The vitreous humor itself is a clear gel that can be removed by a vitrectomy probe inserted through a cannula previously placed in the eye. More specifically, during a vitrectomy, the vitrectomy probe uses its central channel to act like a tiny guillotine, cutting the vitreous into microscopic pieces at high speed. A vacuum is applied to a fluid tube connected to the central channel, which provides suction to remove the cut vitreous.

[0005] During vitrectomy (and other types of eye surgery such as phacoemulsification (cataract extraction), fragmentation, and viscous fluid extraction), where a vacuum is applied to remove fluid along with other substances, controlling and maintaining adequate intraocular pressure (IOP) aids in the efficiency, effectiveness, and safety of the surgery. However, maintaining proper IOP is a careful balancing act between injection and aspiration.

[0006] Venturi vacuum generators are commonly used to provide suction in eye surgery. However, Venturi vacuum generators may have an unstable vacuum pressure or oscillation region near maximum vacuum pressure. For a Venturi vacuum generator configured to deliver up to about 670 mmHg (millimeters of mercury), there may be no oscillations at maximum operation. However, a significant amount of oscillation may occur when the vacuum generator is operated to just below the approximately 550 to 670 mmHg level. That is, the vacuum may be increased and large oscillations may occur before the maximum vacuum is reached.

[0007] As mentioned above, vacuum pressure oscillations resulting in IOP fluctuations can affect the efficiency, effectiveness, and safety of surgery. However, as a practical matter, completely avoiding such oscillations may have drawbacks. That is, keeping the vacuum below a certain level may help to avoid oscillations. Unfortunately, this means keeping the vacuum below a high level, which may only be useful for a portion of the surgery.

[0008] Additionally, it may not be practical to have the option of turning on and ramping up the vacuum before the start of surgery so that the probe needle passes through the oscillation region before it is used. Again, it may not be practical to start surgery by operating below the oscillation region, stop the surgical procedure as it adjusts the throttle as it passes through the oscillation region, and then resume the surgical procedure once it has settled. In either case, the surgeon may not be able to work with a particular vacuum pressure setting during the procedure. Summary of the Invention [Means for solving the problem]

[0009] A surgical system is described. The system includes a pressure source, a shutoff valve for turning on or off a supply pressure or flow to the system, and a pressure regulator for regulating the supply pressure from the source. A venturi vacuum generator is provided in communication with the supply pressure to supply vacuum pressure to an aspiration port of the surgical system. A throttling control proportional valve between the supply pressure regulator and the venturi vacuum generator controls flow to the vacuum generator utilizing a vacuum pressure transducer to sense the vacuum pressure exiting the venturi vacuum generator. Similarly, a venturi inlet pressure transducer is used to sense the inlet pressure to the venturi vacuum generator. A bleed control proportional valve is then utilized to optionally bleed vacuum from the outlet line of the venturi vacuum generator in response to these detections. In this manner, a system controller configured to respond to the detections can control the throttling control proportional valve and the bleed control proportional valve to substantially prevent vacuum oscillations directed to the surgical system.

[0010] Variations of this system may also be obtained, and may realize substantial benefits, so long as some form of damping of oscillations from the Venturi vacuum system is provided. In other words, by driving the fluid flow through the Venturi vacuum generator at a level below the oscillation throttling level threshold, and then increasing the flow to reach and / or exceed the threshold while simultaneously bleeding off a portion of the vacuum flow from the generator, beneficial damping or elimination of vacuum pressure oscillations may be provided in a manner not previously seen. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an exemplary prior art diagram showing vacuum oscillations in a Venturi vacuum system without oscillation minimization. [Diagram 2] FIG. 2 is a schematic diagram of a Venturi vacuum surgical system with oscillation minimization. [Diagram 3] FIG. 3 is a schematic diagram of a vitrectomy performed on a patient's eye with the assistance of the Venturi vacuum system of FIG. [Figure 4] FIG. 4 is a graph illustrating a control method applied in the Venturi vacuum system of FIG. 2 to minimize or eliminate oscillations during the procedure of FIG. [Diagram 5] FIG. 5 is another graph illustrating another control method that may be applied in the Venturi vacuum system of FIG. 2 to minimize or eliminate oscillations during the procedure of FIG. [Figure 6] FIG. 6 is yet another graph illustrating another control method applied in the Venturi vacuum system of FIG. 2 to minimize or eliminate oscillations during the procedure of FIG. [Figure 7] FIG. 7 is a graph showing an oscillation-free vacuum obtained by applying any of the control methods of FIGS. [Figure 8] FIG. 8 is a flow chart summarizing an embodiment employing a Venturi vacuum system and control method to minimize or eliminate oscillations during surgery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it will be understood by those skilled in the art that the described embodiments may be practiced without these specific details. Moreover, numerous variations or modifications may be employed that are still contemplated in the specifically described embodiments.

[0013] The embodiments are described in the context of one particular type of vitrectomy probe procedure. In particular, vitrectomy, in which vitreous humor is removed to address retinal detachment, is illustrated. However, the instruments and control methods detailed herein may be used in a variety of other procedures. That is, application of a Venturi vacuum system with a uniquely tailored anti-oscillation feature may be utilized to address vitreous hemorrhage, macular fold formation, macular holes, floaters, diabetic retinopathy, or a variety of other ocular or non-ocular related conditions. In any case, to the extent that the Venturi vacuum system incorporates the oscillation reduction or elimination features detailed herein, substantial benefits may be realized.

[0014] Referring now to FIG. 1, a graph is shown illustrating a conventional Venturi vacuum surgical system in which oscillation minimization features are not employed. Specifically, a graph is shown showing synchronous vacuum pressure changes from 0 to a maximum value (e.g., 670 mmHg) as a result of an increase in supply pressure or supply flow versus throttling levels from 0 to a level corresponding to maximum vacuum. The throttling level may be the opening rate of a throttling control proportional valve. Vacuum oscillations occur in the region just below the maximum vacuum level (e.g., just below 550-670 mmHg). In such Venturi vacuum systems, it may be undesirable (or impossible) to operate in this range, since vacuum pressure oscillations resulting in IOP fluctuations may affect the efficiency, effectiveness, and safety of surgery. However, once the vacuum reaches a maximum value (e.g., 670 mmHg), the oscillations disappear.

[0015] 2, a schematic diagram of a Venturi vacuum surgical system 100 employing features for minimizing oscillations is shown. That is, a Venturi vacuum generator 150 is employed, similar to other vacuum systems for supporting surgical instruments in the field. The system 100 includes other standard components such as a pressure source 120, a pressure regulator 140, a shutoff valve 130, a throttling device 155, a vacuum pressure transducer 180, and a muffler 160. However, conventional systems are prone to oscillations when such Venturi devices are operated near maximum vacuum. However, as described in detail herein, the illustrated system 100 employs the unique features of a Venturi inlet pressure transducer 175 and a bleed control device 101 to minimize, dampen, and / or eliminate such oscillations.

[0016] 2, in system 100, pressure source 120 generates a fluid flow of air (see 125) toward the venturi vacuum generator 150. Thus, for example, pressure source 120 may be an air pressure source directing 20-40 SLPM (standard liters per minute) of air toward vacuum generator 150. In terms of pressure measurements, approximately 60 PSI (pounds per square inch) is detected at pressure source 120. Of course, this is merely an exemplary situation.

[0017] In a surgical environment, this pressure source 120 may be drawn from a common line that runs throughout the facility, from a mobile base unit, a high pressure cylinder, a compressor, or other suitable pressure source. While this amount of pressure is available to support the air flow 125, a throttling device 155 is provided that is utilized to actually govern the air pressure and flow that reaches the vacuum generator 150. This device 155 may be, among other things, a throttling controlled proportional valve as shown. So, while for example 40 SLPM is available, a maximum throttling of about 30 SLPM may be provided for the illustrated vacuum generator 150 based on its design tolerances and maximum efficiency. This in turn may lead to 60 PSI being available as discussed above, but the throttling maximum is configured to maximize pressure at about 50 PSI for the venturi vacuum generator 150. It is useful to refer to PSI values ​​here since real-time pressure readings are available from the transducers 175, 180 for the oscillation rejection control method detailed below.

[0018] Continuing with the example of a maximum of 50 PSI being supplied to the vacuum generator 150, it will be appreciated that in the range just below maximum throttling (e.g., just below 45-50 PSI), the generator 150 is prone to exhibiting undesirable oscillations. If not addressed, this can affect the performance of the suction facilitated by the system 100 or an instrument at the end of the vacuum line 110. Thus, the vacuum line 110, which is in fluid communication with the venturi generator 150 to generate said suction, is also in fluid communication with a bleed control device 101. This device 101 may be a bleed control proportional valve that, when operated in concert with other functions of the system 100 as described below, may be utilized to dampen or substantially eliminate said oscillations.

[0019] The system 100 of FIG. 2 further comprises a venturi inlet pressure transducer 175 disposed in the fluid path between the throttling device 155 and the venturi vacuum generator 150. This allows real-time monitoring of the actual throttling level to be tracked via the detected pressure at the transducer 175. In particular, the detected pressure may be monitored by a system controller 105 having suitable computing capabilities. The controller 105 may then further adjust the throttling level at the device 155 based on the actual detected pressure from the transducer 175 in a standard feedback manner. For example, if a throttling seen at 40 PSI for the venturi vacuum generator 150 is desired, but a pressure detection at the transducer 175 indicates rather 45 PSI, the controller 105 may make appropriate adjustments to the throttling device 155.

[0020] In the illustrated embodiment, the controller 105 is located remotely from the throttle device 155 and the venturi inlet pressure transducer 175, but may communicate as described above via wireless means. Alternatively, system components containing these and other functions for which controller communication is desirable may be wired together as part of a single mobile or fixed unit.

[0021] 2, the flow 125 through the venturi generator 150 exits towards a muffler device 160. Of course, like other venturi generator devices, the illustrated generator 150 also includes a flow path for vacuum communication away from the generator and ultimately to the vacuum line 110 described above. That is, the flow 125 through the generator 150 ultimately facilitates a vacuum in the vacuum line 110 to assist in surgery, for example as shown in FIG.

[0022] However, and perhaps more notably, the system embodiment shown in FIG. 2 also includes a vacuum communication to the bleed control device 101, as described above. As will be described in more detail below, this device 101 may be actuated to redirect vacuum pressure away from the vacuum line 110 when the pressure is in a region prone to supporting oscillations. So, for example, if the venturi generator 150 is rated for an efficient maximum vacuum of approximately 670 mmHg, it may be prone to exhibit vacuum oscillations when the suction is in the range of 550-670 mmHg unless measures are taken to avoid oscillations. Of course, this is by way of example only. Various other maximum values ​​and possible ranges of oscillations may be contemplated. In any event, in the above example, a vacuum pressure transducer 180 may be placed in fluid communication with the venturi generator 150. So, for example, increasing the restriction in the restriction device 155 may cause the vacuum side of the venturi generator 150 to track closer to the 550-670 mmHg predetermined oscillation region of concern.

[0023] Continuing with the example of the venturi generator 150 with a maximum value of 670 mmHg, as described above, there is more than enough pressure supply 120 available to facilitate the airflow 125 to and through the venturi generator 150 as modified by the throttling device 155. So, for example, at start-up, the throttling device 155 may be instructed by the controller 105 to steadily increase the pressure reaching the generator 150 starting from 0 PSI to about 45 PSI. This may be confirmed through an initial ramp-up of pressure by the inlet pressure transducer 175. Again, the net effect of this ramp-up on the suction side may be monitored directly by the vacuum pressure transducer 180. For example, these detections may confirm whether the ramp-up has resulted in a corresponding expected ramp-up of the vacuum from 0 to 550 mmHg. Furthermore, in response to the ramp-up being above (or below) the expected on the vacuum side, the throttling level may be lowered (or raised) as instructed by the controller 105.

[0024] Continuing with the above example, suction via vacuum line 110 may be applied over the full range of 0-550 mmHg in support of surgery as shown in FIG. 3. However, where the oscillation region, in this example 550-670 mmHg, comes into play, alternative measures may be taken to allow vacuum line 110 to effectively avoid noticeable oscillation to surgery. Specifically, as alluded to above, when the detected vacuum reaches the oscillation region at 550 mmHg, bleed device 101 may be employed to begin bleed of vacuum pressure from venturi generator 150. At the same time, throttling is increased in throttling device 155 such that venturi vacuum generator 150 forms a higher vacuum to cover the vacuum bleed. The net effect is that the vacuum level in vacuum line 110 is maintained at 550 mmHg without oscillation. As described in more detail below, the oscillation region may be predetermined, or controller 105 may be configured to respond to actual detected oscillations from vacuum pressure transducer 180.

[0025] As mentioned above, oscillations are a natural effect of pressure directed to the generator 150 (e.g., 45-50 PSI in this example). In this example, this leads to oscillations at 550-670 mmHg on the vacuum side. Thus, the proportional valve, the bleed device 101, can be opened while being restricted to a high level while exposed to these pressure ranges. In this way, a vacuum of 550-670 mmHg can be achieved in the vacuum line 110 with no corresponding oscillations in this operating region. This is explained in more detail below.

[0026] With particular reference now to FIG. 3, a schematic side cross-sectional view of a patient's eye 250 during a vitrectomy procedure is shown. Specifically, the procedure is assisted by the vacuum line 110 of the system 100 of FIG. 2. As shown, this line 110 is part of a vitrectomy probe needle that terminates in a port 277 for drawing vitreous humor 210 from the eye 250. At the same time, an injection instrument 225 is used to deliver an inert biocompatible fluid 200 to the eye 250 to replace the removed vitreous humor and help maintain a pressure balance therein. In this manner, the stability of the vacuum through the line 110 helps maintain pressure within the eye (intraocular pressure (IOP)).

[0027] Continuing to refer to FIG. 3, the probe needle 110 and the injection tool 225 are supported by the pre-placed cannula 230, 215. This allows for the guidance and support of the device for the surgery. The cannula 215, 230 is small in diameter and relatively short in length. This helps to avoid the risk of damage to the optic nerve 260, retina 275, and other more delicate mechanisms behind the eye 250. Note that the cannula 215, 230 is placed offset in the sclera 270. In this way, damage to the more delicate cornea 290 and lens 280 can be avoided. Thus, various measures are taken to help ensure that inadvertent damage is avoided during surgery. It is in a similar vein that the embodiments of the present application are directed to avoiding unintended movement of the optic nerve 260, retina 275, cornea 290, and lens 280 caused by unstable IOP as a result of vacuum pressure oscillations in the vacuum line 110 during surgery. Specifically, employing the system 100 of FIG. 2 to supply vacuum to the line / needle 110 of FIG. 3 means that sudden or unexpected changes in IOP can be largely, if not completely, eliminated to avoid inadvertent injury during surgery.

[0028] 4, a graph is shown illustrating a Venturi vacuum surgical system 100 in which oscillation minimization is employed. Specifically, a graph is shown illustrating vacuum pressure varying from 0 to a maximum value (e.g., 670 mmHg) as a result of controlling the throttling level of the supply pressure or supply flow, synchronized with the vacuum bleed level to eliminate oscillation. The throttling level may be the opening rate of the throttling control proportional valve 155. The vacuum bleed level may be the opening rate of the vacuum bleed control proportional valve 101.

[0029] In FIG. 4, the vertical axis of the top graph indicates the degree of vacuum starting from no vacuum at the bottom. In connection with what has been discussed above, the throttling device 155 of FIG. 2 may be used to establish an increasing air flow 125 to the venturi vacuum generator 150, ultimately increasing this vacuum over time, as described above. The vertical axis of the middle graph indicates the level of throttling, which may be the percentage opening of the throttling control proportional valve 155. As discussed above, the venturi vacuum surgical system 100 may employ a bleed device 101 to bleed vacuum pressure from the venturi generator 150 as needed. The vertical axis of the bottom graph indicates the level of bleed, which may be the percentage opening of the bleed control proportional valve 101. In the graph of FIG. 4, the horizontal axis is synchronized to represent the passage of time as the vacuum changes with the change in throttling and bleed levels shown on the vertical axis.

[0030] Referring again to FIG. 1, as discussed above, conventional Venturi vacuum surgical systems that do not employ oscillation minimization features may exhibit a significant amount of vacuum oscillation in the region just below the maximum vacuum level (e.g., 550-670 mmHg in this embodiment). However, once the vacuum reaches the maximum value (e.g., 670 mmHg), the oscillation may disappear. Now with continued reference to FIG. 4, rather than allowing this oscillating range of vacuum to exist through the vacuum line 110 of FIG. 2 (which continues to the probe needle 110 of FIG. 3), the system 100 employs an oscillation elimination control method as shown in FIG. 4.

[0031] At a given vacuum level (e.g., 540 mmHg) below the region of oscillation (e.g., 550-670 mmHg), the restriction may be immediately brought to and maintained at its maximum as shown in FIG. 4. At this same point, a bleed level (e.g., maximum bleed level) may be applied via the bleed device 101 of FIG. 2. As shown in FIG. 4, this bleed may be reduced over time as necessary to obtain vacuum levels between 540 mmHg and 670 mmHg, or the maximum vacuum of 670 mmHg may be maintained at a lower bleed level (e.g., 0 bleed). The effect of the control method of FIG. 4 employed in the Venturi vacuum surgical system 100 is that the entire range of vacuum levels (e.g., 0-670 mmHg) may be achieved without oscillation.

[0032] With additional reference to FIG. 2, the above-described control method may be managed by the controller 105 of FIG. 2. For example, the vacuum level may be monitored at the vacuum transducer 180. When a predetermined vacuum level is reached, for example just below 540 mmHg or 550 mmHg, the throttling device 155 is maximized as described above to correspond to maximum vacuum (e.g., 670 mmHg). Similarly, a confirmatory pressure reading of 50 PSI may be obtained at the inlet transducer 175. Maximum bleed may be simultaneously applied at this point as described above. The processor of the controller 105 may then employ a PID (proportional-integral-derivative) algorithm based, inter alia, on real-time venturi vacuum and inlet pressure detection to subsequently adjust the throttling and bleed levels to obtain a vacuum level between 540 and 670 mmHg to maintain maximum vacuum (e.g., 670 mmHg).

[0033] With particular reference to FIG. 5, a predefined vacuum level is not utilized as in the control method shown in FIG. 4. Instead, the controller 105 of FIG. 2 may initiate such PID control of throttling and bleed when an oscillation is first detected. The determination of an oscillation may be based on a sudden, uncommanded change in the level of vacuum, the magnitude of which is greater than a predefined threshold so that no false positives are generated by noise signals. For example, if the predefined threshold is set to 20 mmHg, then the oscillation control method may be triggered by the first oscillation greater than 20 mmHg. As can be seen in FIG. 5, the first oscillation is shown, which may be a vacuum jump (at 550 mmHg) whose magnitude exceeds the 20 mmHg threshold. Once this is detected by the controller 105, the same PID algorithm as in FIG. 4 may then be applied (i.e. the throttling may be immediately brought to its maximum value and the bleed level may be applied to obtain the desired vacuum through the bleed device 101).

[0034] Given the millisecond response time capabilities of such a system 100 in its PID control algorithm for obtaining the desired vacuum level in the vacuum line 110, this manner of detecting initial oscillations and / or sudden jumps in the throttle and bleed levels is unlikely to result in measurable oscillations that would be felt by the surgeon during surgery as shown in FIG. 3.

[0035] Of course, it may be advantageous to avoid sudden jumps in the throttle and bleed levels. Thus, in one embodiment, a transient approach may be taken by increasing the throttle and introducing bleed. In this embodiment, the increase in throttle is more stable by introducing bleed well before the lower limit of the oscillation region is reached. It may be advantageous to start the coordination of bleed and throttling much earlier than just below the oscillation region. Specifically, referring to FIG. 6, a graph illustrating such a transient approach is shown. Within the transient control vacuum range, both the throttle and bleed levels are under PID control to achieve the commanded vacuum level. Outside the transient control vacuum range, all control is the same as the control method of FIG. 4.

[0036] Although not clearly shown, it is clear in Figure 6 that the vacuum level rises more steadily. Note that the time reflected on the horizontal axis occupies a short period, perhaps about 5-20 milliseconds, during which the throttle rises more steadily to its maximum value (see middle graph). Referring to the bottom graph, the same steady rise to bleed air is also reflected during this same period.

[0037] Note that after the transient period, the maintenance of maximum throttling and the drawdown of bleed air proceeds as described above. However, as a practical matter, the vacuum range is more stable. Note, for example, in the top graph of FIG. 5, that there is no initial vacuum jump. Furthermore, both the throttling and bleed levels change gradually, thereby avoiding instantaneous fluctuations in vacuum level and long settling times in throttling and bleed levels associated with abrupt jumps. Finally, an enhanced control method is provided herein.

[0038] Indeed, with particular reference now to Figure 7, there is shown a graph illustrating the oscillation-free vacuum obtained by application of the control method of Figure 6. Note that the full vacuum range is now available without oscillations or sudden vacuum jumps.

[0039] 8, a flow chart is shown summarizing an embodiment employing a Venturi vacuum system. That is, as shown at 610 and 630, airflow is induced to a Venturi vacuum generator to obtain a vacuum suction from the Venturi vacuum generator. Pressure may be monitored in terms of both airflow to the vacuum generator and the generated vacuum, as noted at 650. Thus, a processor may adjust the throttling of airflow to the vacuum generator and coordinately bleed the vacuum pressure (see 670) to avoid vacuum oscillations. Finally, an oscillation-free vacuum is provided for use in assisting surgery, as shown at 690.

[0040] The embodiments described herein above include a venturi-assisted vacuum system that has the unique ability to substantially prevent oscillations from reaching the surgical suction instruments assisted by the system. By avoiding the effects of oscillations on the surgical instruments as detailed herein, not only can the surgeon operate in a more stable manner, but the surgeon can also receive continuous vacuum assistance without having to interrupt the procedure. That is, the need to pause the procedure or operate only outside of a specific area of ​​vacuum assistance may be avoided. Rather, this allows the surgeon to have continuous available suction throughout the entire vacuum range from 0 to maximum.

[0041] The foregoing description has been presented with reference to the presently preferred embodiment. However, other embodiments and / or features of embodiments disclosed but not detailed above may be employed. Moreover, those skilled in the art to which these embodiments pertain will appreciate that still other modifications and changes in the described structure and method of operation may be made without significantly departing from the principles and scope of these embodiments. Additionally, the foregoing description should not be read as relating solely to the exact structure described and shown in the accompanying drawings, but rather as consistent with and in support of the following claims, which shall have their fullest and most reasonable scope. The present disclosure also includes the following aspects. [Aspect 1] 1. A method of generating a venturi vacuum, the method comprising: directing a regulated pressure supply from a pneumatic pressure source to a venturi vacuum generator to provide a vacuum to the vacuum line; monitoring an inlet pressure to said vacuum generator with a venturi inlet pressure transducer; monitoring a vacuum pressure in the vacuum line connected to the vacuum generator with a vacuum pressure transducer; obtaining monitored inlet and vacuum pressure values ​​in a system controller; adjusting, by the controller based on the monitored values, at least one of a throttling level of the pressure supply to the vacuum generator and a vacuum pressure extraction level from the vacuum line to substantially prevent vacuum oscillations in the vacuum line; A method comprising: [Aspect 2] The adjusting step comprises: Adopting a proportional valve for controlling the throttle to maintain the throttle level at maximum throttle to prevent vacuum oscillation; employing a bleed control proportional valve to control said bleed to achieve an operator determined vacuum level; 2. The method of embodiment 1, further comprising: [Aspect 3] The adjusting step comprises: maintaining a set vacuum bleed level to prevent said oscillations; Employing a throttling controlled proportional valve to achieve operator determined vacuum levels; 2. The method of embodiment 1, further comprising: Aspect 4 The adjusting step comprises: Detecting a predetermined vacuum level below a vacuum level oscillation region; moving the throttling control proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; opening a bleed control proportional valve to a predetermined maximum level based on said detecting; employing a PID (proportional-integral-derivative) control algorithm in said controller to adjust a throttling proportional valve in cooperation with said monitored value to maintain a maximum venturi inlet pressure; adjusting the bleed control proportional valve to achieve an operator determined vacuum pressure level; 2. The method of embodiment 1, further comprising: Aspect 5 The adjusting step comprises: Detecting a predetermined vacuum level below a vacuum level oscillation region; employing a PID control algorithm in said controller to take into account said monitored values ​​in real time to adjust the throttling control proportional valve and the bleed control proportional valve in response to said sensing of said predetermined vacuum level to obtain an operator determined vacuum level within a predetermined transient vacuum range; Detecting a vacuum level above a predetermined transient vacuum range but below the vacuum level oscillation region; employing the PID control algorithm to regulate the throttling proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; adjusting the bleed control proportional valve to achieve an operator determined vacuum pressure level; 2. The method of embodiment 1, further comprising: Aspect 6 The adjusting step comprises: detecting vacuum level oscillations from the vacuum pressure transducer; opening the throttle control proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; opening the bleed control proportional valve to a predetermined maximum level; employing a PID control algorithm in said controller to ensure that said throttle control proportional valve is maintained at said maximum value and taking into account said monitored value in real time to adjust said bleed control proportional valve to provide a vacuum level determined by an operator; 2. The method of embodiment 1, further comprising: Aspect 7 1. A Venturi vacuum system comprising: A Venturi vacuum generator; a pressure source for inducing pressure in the vacuum generator; a venturi inlet pressure transducer for monitoring the pressure at the vacuum generator; a vacuum line receiving a vacuum pressure from the vacuum generator; a vacuum pressure transducer for monitoring the vacuum pressure; a system controller that directs a throttling device to adjust the throttling of the pressure induced to the vacuum generator and directs a bleed device to pull a vacuum from the vacuum line based on real-time monitoring of the pressure induced to the vacuum generator and the vacuum pressure in the vacuum line connected to the vacuum generator; A venturi vacuum system comprising: Aspect 8 8. The venturi vacuum system of claim 7, wherein the directing of the throttling device and the bleed device is to substantially avoid oscillations of the vacuum pressure in the vacuum lines. Aspect 9 9. The venturi vacuum system of claim 8, wherein the throttling device is a throttling control proportional valve and the bleed control device is a bleed control proportional valve. Aspect 10 9. The venturi vacuum system of claim 8, wherein the system controller comprises a processor that executes a PID algorithm for the avoidance of the oscillations. Aspect 11 8. The Venturi vacuum system of claim 7, wherein the vacuum line terminates in a surgical instrument. Aspect 12 12. The Venturi vacuum system of claim 11, wherein the surgical instrument is a vitrectomy probe. Aspect 13 1. A method of damping oscillations from a venturi vacuum system, the method comprising: driving a flow of fluid through a venturi vacuum generator at a pressure level below a corresponding oscillation region of vacuum pressure in a vacuum line running from said generator; increasing the flow in the vacuum generator to a pressure in the vacuum line to reach the oscillation region; applying a pressure bleed to the vacuum line during the increase to dampen the oscillation; and A method comprising: Aspect 14 employing an inlet pressure transducer at the vacuum generator to determine the flow of pressure at the vacuum generator prior to the increase; employing a vacuum pressure transducer in the vacuum line to determine the vacuum pressure in the vacuum line prior to the bleed; 14. The method of embodiment 13, further comprising: Aspect 15 15. The method of claim 14, further comprising executing a PID based algorithm program in a processor of a controller in communication with the transducer to command the increase in pressure of the flow in the generator and the bleed to the vacuum line.

Claims

1. 1. A method of generating a venturi vacuum, the method comprising: directing a regulated pressure supply from a pneumatic pressure source to a venturi vacuum generator to provide a vacuum to the vacuum line; monitoring an inlet pressure to said venturi vacuum generator with a venturi inlet pressure transducer; monitoring a vacuum pressure in the vacuum line connected to the Venturi vacuum generator with a vacuum pressure transducer; obtaining monitored inlet and vacuum pressure values ​​in the controller; adjusting, by the controller based on the monitored values, at least one of a throttling level of the pressure supply to the venturi vacuum generator and a vacuum pressure extraction level from the vacuum line to substantially prevent vacuum oscillations in the vacuum line; A method comprising:

2. The adjusting step comprises: employing a proportional valve for controlling the throttle to maintain the throttle level at maximum throttle to prevent vacuum oscillation; Employing a proportional bleed control valve that controls the bleed to achieve an operator determined vacuum level; The method of claim 1 further comprising:

3. The adjusting step comprises: maintaining a set vacuum bleed level to prevent said vacuum oscillations; Employing a throttling controlled proportional valve to achieve operator determined vacuum levels; The method of claim 1 further comprising:

4. The adjusting step comprises: Detecting a predetermined vacuum level below a vacuum level oscillation region; moving the throttling control proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; opening a bleed control proportional valve to a predetermined maximum level based on said detecting; employing a PID (proportional-integral-derivative) control algorithm in said controller to adjust a throttling proportional valve in cooperation with said monitored value to maintain a maximum venturi inlet pressure; adjusting the bleed control proportional valve to achieve an operator determined vacuum pressure level; The method of claim 1 further comprising:

5. The adjusting step comprises: Detecting a predetermined vacuum level below a vacuum level oscillation region; employing a PID control algorithm in said controller to take into account said monitored values ​​in real time to adjust the throttling control proportional valve and the bleed control proportional valve to obtain an operator determined vacuum level within a predetermined transient vacuum range in response to detecting said predetermined vacuum level; Detecting a vacuum level above a predetermined transient vacuum range but below the vacuum level oscillation region; employing the PID control algorithm to regulate the throttling proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; adjusting the bleed control proportional valve to achieve an operator determined vacuum pressure level; The method of claim 1 further comprising:

6. The adjusting step comprises: detecting vacuum level oscillations from the vacuum pressure transducer; opening the throttle control proportional valve to a maximum value corresponding to a maximum vacuum of the venturi vacuum generator; opening the bleed control proportional valve to a predetermined maximum level; employing a PID control algorithm in said controller to ensure that said throttle control proportional valve is maintained at said maximum value and taking into account said monitored value in real time to adjust said bleed control proportional valve to provide a vacuum level determined by an operator; The method of claim 1 further comprising:

7. 1. A Venturi vacuum system comprising: A Venturi vacuum generator; a pressure source for inducing pressure in the venturi vacuum generator; a venturi inlet pressure transducer for monitoring the pressure at the venturi vacuum generator; a vacuum line receiving vacuum pressure from the Venturi vacuum generator; a vacuum pressure transducer for monitoring the vacuum pressure; a system controller that directs a throttling device to adjust the throttling of the pressure induced to the venturi vacuum generator and directs a bleed device to pull a vacuum from the vacuum line based on real-time monitoring of the pressure induced to the venturi vacuum generator and the vacuum pressure in the vacuum line connected to the venturi vacuum generator; Equipped with 20. A venturi vacuum system, wherein the directing of the throttling device and the bleed device is to substantially avoid oscillations of the vacuum pressure in the vacuum line.

8. 8. The venturi vacuum system of claim 7, wherein said throttling device is a throttling controlled proportional valve and said bleed device is a bleed controlled proportional valve.

9. 8. The venturi vacuum system of claim 7, wherein the system controller comprises a processor that executes a PID algorithm for the avoidance of the oscillations.

10. The Venturi vacuum system of claim 7 , wherein the vacuum line terminates in a surgical instrument.

11. The Venturi vacuum system of claim 10 , wherein the surgical instrument is a vitrectomy probe.

12. 1. A method of damping oscillations from a venturi vacuum system, the method comprising: driving a flow of fluid through a venturi vacuum generator at a pressure level below a corresponding oscillation region of vacuum pressure in a vacuum line running from said venturi vacuum generator; increasing the flow in the venturi vacuum generator to a pressure in the vacuum line to reach the oscillation region; applying a pressure bleed to the vacuum line during the increase to dampen the oscillation; and A method comprising:

13. employing an inlet pressure transducer at the venturi vacuum generator to determine the flow of pressure at the venturi vacuum generator prior to the increase; employing a vacuum pressure transducer in the vacuum line to determine the vacuum pressure in the vacuum line prior to the bleed; The method of claim 12 further comprising:

14. 14. The method of claim 13, further comprising executing a PID based algorithm program in a processor of a controller in communication with the inlet pressure transducer and the vacuum pressure transducer to command the increase in pressure of the flow in the venturi vacuum generator and the bleed to the vacuum line.

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