Patent Description:
The optical elements of the eye include both a cornea (at the front of the eye) and a lens within the eye. The lens and cornea work together to focus light onto the retina at the back of the eye. The lens also changes in shape, adjusting the focus of the eye to vary between viewing near objects and far objects. The lens is found just behind the pupil and within a capsular bag, the capsular bag being a thin, relatively delicate structure which separates the eye into anterior and posterior chambers.

With age, clouding of the lens or cataracts is fairly common. Cataracts may form in the hard central nucleus of the lens, in the softer peripheral cortical portion of the lens, or at the back of the lens near the capsular bag. Cataracts can be treated by the replacement of the cloudy lens with an artificial lens. Phacoemulsification systems often use ultrasound energy to fragment the lens and aspirate the lens material from within the capsular bag. This may allow the capsular bag to be used for positioning of the artificial lens, and maintains the separation between the anterior portion of the eye and the vitreous humor in the posterior chamber of the eye.

During cataract surgery and other therapies of the eye, accurate control over the volume of fluid within the eye is highly beneficial. For example, while ultrasound energy breaks up the lens and allows it to be drawn into a treatment probe with an aspiration flow, a corresponding irrigation flow may be introduced into the eye so that the total volume of fluid in the eye does not change excessively. If the total volume of fluid in the eye is allowed to get too low at any time during the procedure, the eye may collapse and cause significant tissue damage. Similarly, excessive pressure within the eye may strain and injure tissues of the eye.

While a variety of specific fluid transport mechanisms may be used in phacoemulsification and other treatment systems for the eyes, aspiration flow systems can generally be classified in two categories: <NUM>) volumetric-based aspiration flow systems using positive displacement pumps (e.g. peristaltic); and <NUM>) vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface within a reservoir (e.g. Venturi). Both systems may be incorporated into one treatment system and/or cassette. Cassette ("pack") systems can be used to couple peristaltic pump drive rotors and/or vacuum systems of the surgical consoles to an eye treatment handpiece, with the flow network conduit of the cassette being disposable to avoid cross-contamination between different patients.

In traditional ophthalmic surgery, fluid from the fluid source is also used to irrigate the eye during a procedure. As mentioned above, the irrigation fluid serves to maintain proper intraocular pressure and to replace fluid during aspiration of emulsified lens fragments. The irrigation source is typically a <NUM> bottle or drip bag of saline solution. One issue is that, during ophthalmic surgery, the potential exists for the saline solution to be depleted, turning the irrigation dry. Though an unlikely scenario, the potential consequences are substantial - severe cornmeal burns, capsular tear requiring vitrectomy or additional vitro-retinal surgery, damage to the structure of the eye, and/or loss of vision.

To mitigate such occurrences, staff operating a system typically begin each procedure with a fresh irrigation source prior to each case, and monitor the fluid visually throughout surgery. In some instances, flow sensors are used to measure flow out of the irrigation source. However, conventional configurations do not efficiently provide relative irrigation source volumes and only provide warnings when a detected flow indicates a very low irrigation source volume. As such, improvements are needed in the art to address these issues.

Further, <CIT> discloses an alarm capable of determining the flow time remaining of irrigation fluid. The device can detect a partial or complete blockage in the system or empty fluid bag and alert medical personnel locally or remotely as required, and is capable of calculating the time remaining before the CBI irrigation fluid in the irrigation fluid bag reaches a pre-set level that necessitates changing the bag or the actual time of day or night when the irrigation will be approaching the critical level. Additionally, the user can be alerted to the CBI irrigation fluid in the irrigation fluid bag reaching a pre-set level that necessitates changing the bag before the fluid level becomes critical.

A phacoemulsification system is known from <CIT>.

The drawings illustrate disclosed embodiments and/or aspects and, together with the description, serve to explain the principles of the invention, the scope of which is determined by the claims.

It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for the purpose of clarity, many other elements found in typical surgical, and particularly optical surgical, apparatuses, systems, and methods. Those of ordinary skill in the art may recognize that other elements and/or steps are desirable and/or required in implementing the present invention. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements and steps is not provided herein. The disclosure herein is directed to all such variations and modifications to the disclosed elements and methods known to those skilled in the art.

Referring now to <FIG>, a system <NUM> for treating an eye E of a patient P generally includes an eye treatment probe handpiece <NUM> coupled with a console <NUM> by a cassette <NUM>. Handpiece <NUM> generally includes a handle for manually manipulating and supporting an insertable probe tip. The probe tip has a distal end which is insertable into the eye, with one or more lumens in the probe tip allowing irrigation fluid to flow from console <NUM> and/or cassette <NUM> into the eye. Aspiration fluid may also be withdrawn through a lumen of the probe tip, with console <NUM> and cassette <NUM> generally including a vacuum aspiration source, a positive displacement aspiration pump, or both to help withdraw and control a flow of surgical fluids into and out of eye E. As the surgical fluids may include biological materials that should not be transferred between patients, cassette <NUM> will often comprise a sterilizable (or alternatively, disposable) structure, with the surgical fluids being transmitted through flexible conduits <NUM> of cassette <NUM> that avoid direct contact in between those fluids and the components of console <NUM>.

When a distal end of the probe tip of handpiece <NUM> is inserted into an eye E, for example, for removal of a lens of a patient P with cataracts, an electrical conductor and/or pneumatic line (not shown) may supply energy from console <NUM> to an ultrasound transmitter of handpiece <NUM>, a cutter mechanism, or the like. Alternatively, handpiece <NUM> may be configured as an irrigation/aspiration (I/A) and/or vitrectomy handpiece. Also, the ultrasonic transmitter may be replaced by other means for emulsifying a lens, such as a high energy laser beam. The ultrasound energy from handpiece <NUM> helps to fragment the tissue of the lens, which can then be drawn into a port of the tip by aspiration flow. So as to balance the volume of material removed by the aspiration flow, an irrigation flow through handpiece <NUM> (or a separate probe structure) may also be provided, with both the aspiration and irrigation flows being controlled by console <NUM>.

To avoid cross-contamination between patients without incurring excessive expenditures for each procedure, cassette <NUM> and its flexible conduits <NUM> may be disposable. However, the flexible conduit or tubing may be disposable, with the cassette body and/or other structures of the cassette being sterilizable. Cassette <NUM> may be configured to interface with reusable components of console <NUM>, including, but not limited to, peristaltic pump rollers, a Venturi or other vacuum source, a controller <NUM>, and/or the like.

Console <NUM> may include controller <NUM>, which may include an embedded microcontroller and/or many of the components common to a personal computer, such as a processor, data bus, a memory, input and/or output devices (including a user interface <NUM> (e.g. touch screen, graphical user interface (GUI), etc.), and the like. Controller <NUM> will often include both hardware and software, with the software typically comprising machine readable code or programming instructions for implementing one, some, or all of the methods described herein. The code may be embodied by a tangible media such as a memory, a magnetic recording media, an optical recording media, or the like. Controller <NUM> may have (or be coupled with) a recording media reader, or the code may be transmitted to controller <NUM> by a network connection such as an internet, an intranet, an Ethernet™, a wireless network, or the like. Along with programming code, controller <NUM> may include stored data for implementing the methods described herein, and may generate and/or store data that records parameters corresponding to the treatment of one or more patients. Many components of console <NUM> may be found in or modified from known commercial phacoemulsification systems from Abbott Medical Optics, Inc. of Santa Ana, Calif. ; Alcon Manufacturing, Ltd. Worth, Tex. , Bausch and Lomb of Rochester, N. , and other suppliers.

Referring now to <FIG>, a simplified surgical console is illustrated, where a fluid path may be demonstrated under an exemplary embodiment. In this example, an irrigation source <NUM> may be configured as a bottle or bag hanging from an IV pole hanger <NUM>. It is understood by those skilled in the art that, while an integrated IV pole is illustrated, other configurations, utilizing standalone/static IV poles, or other suitable configurations, are contemplated by the present disclosure.

An exemplary irrigation path for fluid may be realized via tubing cassette <NUM> having cassette tubing interface at fluidics panel <NUM>, which receives fluid from irrigation source <NUM> via drip chamber <NUM>. Irrigation line 156A and aspiration line <NUM> are coupled to handpiece <NUM>. Irrigation fluid may flow from drip chamber <NUM> through the irrigation tubing into tubing cassette <NUM>. Irrigation fluid may then flow from the tubing cassette through handpiece irrigation line 156A which may be coupled to an irrigation port on handpiece <NUM>. Aspirated fluid may flow from handpiece aspiration line <NUM> back to tubing cassette <NUM> and into a waste collection bag <NUM>. A touch screen display <NUM> may be provided to display system operation conditions and parameters, and may include a user interface (e.g., touch screen, keyboard, track ball, mouse, etc. - see controller <NUM> of <FIG>) for entering data and/or instructions to the system of <FIG>.

Referring to <FIG>, an exemplary cassette system showing some of the components and interfaces that may be employed in a phaco system, such as ones illustrated in <FIG> Handpiece <NUM> may be connected to (or coupled with) the input side of fluid vacuum sensor <NUM>, typically by conduits <NUM> which comprise fluid pathways such as fluid pathway <NUM>. The output side of fluid vacuum sensor <NUM> is connected to flow selector valve <NUM> within cassette <NUM> via fluid pathway <NUM>. The exemplary embodiment may configure flow selector valve <NUM> to interface between handpiece <NUM>, balanced saline solution (BSS) fluid bottle <NUM>, pump <NUM>, which is shown as a peristaltic pump but may be another type of pump, and reservoir <NUM>. In this configuration, the system may operate flow selector valve <NUM> to connect handpiece <NUM> with BSS fluid bottle <NUM>, reservoir <NUM> or with pump <NUM> based on signals received from console <NUM> resulting from the surgeon's input to user interface <NUM>.

The flow selector valve <NUM> illustrated in <FIG> provides a single input port and may connect port '<NUM>' to one of three available ports numbered '<NUM>', '<NUM>', and "<NUM>". The exemplary embodiment is not limited to one flow selector valve, and may be realized using two flow selector valves each having at least two output ports, possibly connected together to provide the functionality described herein. For example, a pair of two output port valves may be configured in a daisy chain arrangement, where the output port of a first valve is directly connected to the input port of a second valve. Console <NUM> may operate both valves together to provide three different flow configurations. For example, using two valves, valve one and valve two, valve one may use output port one, which is the supply for valve two. Valve two may connect to one of two ports providing two separate paths. When valve one connects its input port to its second output port rather than the output port that directs flow to the second valve, a third path is provided.

It is also envisioned that flow selector valve <NUM> may be or comprise one or more pinch valves. The one or more pinch valves may be located along fluid pathway <NUM> and/or <NUM>, or any other fluid pathway as discussed herein. Further, there may be one or more fluid pathways coupled with handpiece <NUM> and extending to various components of cassette <NUM>, including a first fluid pathway from fluid vacuum sensor <NUM> to collector <NUM> via pump <NUM> and/or a second fluid pathway to reservoir <NUM>. In another embodiment, fluid pathway <NUM> is a single fluid pathway that couples with fluid vacuum sensor <NUM>. From fluid vacuum sensor <NUM>, the single fluid pathway <NUM> may divide into two fluid pathways, one to collector <NUM> via pump <NUM> and one to reservoir <NUM>. Further, one or more pinch valves and/or flow selector valve <NUM> may be located along the fluid pathway between fluid vacuum sensor <NUM> and collector <NUM> and/or between fluid vacuum sensor <NUM> and reservoir <NUM>.

Thus while a single flow selector valve <NUM> is illustrated in <FIG>, it is to be understood that this illustration represents a flow selector valve arrangement, including one or more flow selector valves performing the functionality described herein, and is not limited to a single device or a single flow selector valve. In the exemplary fluid vacuum sensor <NUM>, a strain gauge or other suitable component may communicate or signal information to console <NUM> to provide an amount of vacuum sensed in the handpiece fluid pathway <NUM>. Console <NUM> may determine the actual amount of vacuum present based on the communicated information.

Fluid vacuum sensor <NUM> monitors flow into and out of the line, and can be used to determine when flow should be reversed, such as encountering a certain pressure level (e.g. in the presence of an occlusion), and based on values obtained from the fluid vacuum sensor <NUM>, the system may control selector valve <NUM> and the pumps illustrated. It is to be understood that while components presented in <FIG> and other drawings of the present application are not shown connected to other system components, such as console <NUM>, they are in fact connected for the purpose of monitoring and control of the components illustrated.

With respect to fluid vacuum sensor <NUM>, emergency conditions such as a dramatic drop or rise in pressure may result in a type of fail-safe operation. The exemplary embodiment employs fluid vacuum sensor <NUM> to monitor the flow conditions and provide signals representing flow conditions to the system such as via console <NUM> for the purpose of controlling components shown including but not limited to flow selector valve <NUM> and the pumps shown. The fluid pathways or flow segments of surgical cassette system <NUM> may include the fluid connections, for example flexible tubing, between each component represented with solid lines in <FIG>.

Vacuum pump arrangement <NUM> is typically coupled with console <NUM>, and may be connected with reservoir <NUM> via fluid pathway or flow segment <NUM>. In the configuration shown, vacuum pump arrangement <NUM> includes a pump <NUM>, such as a venturi pump and an optional pressure regulator <NUM> (and valve (not shown)), but other configurations are possible. In this arrangement, vacuum pump arrangement <NUM> may operate to remove air from the top of reservoir <NUM> and deliver the air to atmosphere (not shown). Removal of air from reservoir <NUM> in this manner may reduce the pressure within the reservoir, which reduces the pressure in the attached fluid pathway <NUM>, to a level less than the pressure within eye <NUM>. A lower reservoir pressure connected through flow selector valve <NUM> may cause fluid to move from the eye, thereby providing aspiration. The vacuum pump arrangement <NUM> and reservoir <NUM> can be used to control fluid flow into and out of reservoir <NUM>.

The optional pressure regulator <NUM> may operate to add air to the top of reservoir <NUM> which in turn increases pressure and may force the air-fluid boundary <NUM> to move downward. Adding air into reservoir <NUM> in this manner may increase the air pressure within the reservoir, which increases the pressure in the attached fluid aspiration line <NUM> to a level greater than the pressure within eye <NUM>. A higher reservoir pressure connected through flow selector valve <NUM> may cause fluid to move toward eye <NUM>, thereby providing venting or reflux.

The exemplary embodiment may involve peristaltic operation, aspirating fluid from eye <NUM> to collector <NUM> illustrated in <FIG>, or venting fluid to the eye <NUM> to reduce the amount of pressure in the aspiration line (where such venting is only shown from BSS bottle <NUM> in <FIG>). Peristaltic pumping is generally understood to those skilled in the art, and many current machines employ peristaltic and/or venturi pumps as the vacuum or pressure sources. Generally, a peristaltic pump has fluid flowing through a flexible tube and a circular rotor with a number of rollers attached to the periphery of the circular rotor. As the rotor turns, fluid is forced through the tube. Venturi pumping, or aspiration or aspirator pumping, produces the vacuum using the venturi effect by providing fluid through a narrowing tube. Because of the narrowing of the tube, the speed at which the fluid travels through the tube increases and the fluid pressure decreases (the "Venturi effect"). As may be appreciated, operating pumps in one direction or another can change the pressure and the operation of the associated device, such as the operation of the cassette in the exemplary embodiment.

Referring now to <FIG>, another system is illustrated. <FIG> generally highlights the surgical aspiration and irrigation fluid control elements included within the cassette <NUM> and console <NUM>, with the irrigation components often being relatively straightforward. A BSS fluid bottle <NUM> of console <NUM> optionally provides irrigation fluid pressure control by relying at least in part on a gravity pressure head that varies with a height of BSS fluid bottle <NUM> or the like. An irrigation on/off pinch valve <NUM> may generally include a short segment of a flexible conduit of cassette <NUM>, which can be engaged and actuated by an actuator of console <NUM>, with a surface of cassette body <NUM> often being disposed opposite the actuator to facilitate closure of the conduit lumen. Alternative irrigation flow systems may include positive displacement pumps, alternative fluid pressurization drive systems, fluid pressure or flow modulating valves, as discussed above, and/or the like.

Aspiration flow path <NUM> couples an aspiration port in the tip of handpiece <NUM> with pump <NUM> and/or a reservoir <NUM>. Fluid aspirated through handpiece <NUM> may be contained in reservoir <NUM> regardless of whether the aspiration flow is induced by pump <NUM> or vacuum pump arrangement <NUM>. When valve <NUM> is closed and pump <NUM> is in operation, pumping of the aspiration flow may generally be directed by the pump, independent of the pressure in the reservoir <NUM>. The aspiration flow may flow through conduit 54a. Conversely, if pump <NUM> is a peristaltic pump, when pump <NUM> is off, flow through the pump may be halted by pinching of the elastomeric tubing arc of the peristaltic pump by one or more of the individual rollers of the peristaltic pump rotor. Hence, any aspiration fluid drawn into the aspiration network (fluid pathways) when pump <NUM> is off will typically involve the opening of a selector control valve <NUM> so that the aspiration port of the probe is in fluid communication with reservoir <NUM>. Alternatively, communication with vacuum pump arrangement <NUM> may be accomplished by disengaging the peristaltic probe drive from the elastomeric tubing. The pressure within reservoir <NUM> may be maintained at a controlled vacuum level, often at a fixed vacuum level, by vacuum pump arrangement <NUM>. Vacuum pump arrangement <NUM> may comprise a vacuum (e.g. Venturi) pump, a rotary vane pump, a vacuum source, pressure regulator, or the like. Aspiration fluid that drains into reservoir <NUM> may be removed by pump <NUM> and directed to collector <NUM>. Vacuum pressure at the surgical handpiece may be maintained within a desired range through control of the fluid level in reservoir <NUM>.

Referring now to <FIG>, an interface <NUM> between cassette <NUM> and console <NUM> is schematically illustrated. Many of the fluid network structures described above regarding <FIG> and <FIG> include or make use of corresponding elements of cassette <NUM> and the console <NUM>. For example, with respect to <FIG>, fluid vacuum sensor <NUM> may be included in a pressure sensing system which includes a pressure sensor 201a having a pressure chamber and a surface that moves in response to variations in the pressure in the chamber. Axial movement of the pressure sensor surface may be determined using a pressure receiver 201b. In the exemplary embodiments, direction of movement of the pressure sensor surface may be aligned with a mounting axis <NUM> of cassette <NUM>, representing a direction of movement of cassette <NUM> during mounting of cassette <NUM> to console <NUM>.

Similarly, selector valve <NUM> may make use of a resilient valve conduit 58a in cassette <NUM> that is engaged by an actuator 58b of console <NUM>. As described above, pump <NUM> may include a conduit 54a of cassette <NUM> engaged by a peristaltic rotor 54b of console <NUM>, with the interface <NUM> effecting engagement between the conduit 54a and the peristaltic rotor 54b. A vacuum coupler 72a of cassette <NUM> may engage a vacuum coupler 72b of console <NUM> so as to allow vacuum pump arrangement <NUM> to apply a vacuum to reservoir <NUM> (See <FIG>). Vacuum tank <NUM> may be coupled with a fluid detector 74b of console <NUM> using a mechanical, electrical, or light fluid presence detector system so as to allow controller <NUM> of console <NUM> to determine when it is appropriate to energize pump <NUM>. Rather than simply detecting the presence of fluid, alternative embodiments might employ a more complex fluid level sensing system which determines a quantity or volume of fluid in the tank for purposes of selectively energizing pump <NUM>. Pump <NUM> includes a conduit 60a of cassette <NUM> and a peristaltic rotor 60b of console <NUM>. Irrigation valve <NUM> may include a resilient valve conduit 48a of cassette <NUM> and a valve actuator 48b of console <NUM>.

Engagement and alignment between cassette <NUM> and the interfacing structures of console <NUM> may be achieved through a variety of mechanisms, some of which are described in <CIT> and <CIT>. A cassette <NUM> may generally have a height and a width which generally are greater than a thickness of cassette <NUM> along a mounting axis, allowing the interfacing fluid pathway network elements of cassette <NUM> and corresponding components of console <NUM> to be distributed in a roughly planar configuration. In addition to the individual interfaces, cassette <NUM> may generally include a cassette body <NUM> with positioning surfaces <NUM> and <NUM> that engage corresponding cassette receptacle surfaces <NUM> of console <NUM>. Cassette receptacle surfaces <NUM> define a cassette receptacle area that receives and positions cassette <NUM>. In one exemplary embodiment, cassette <NUM> is manually supported and advanced along mounting axis <NUM> until positioning surfaces <NUM> engages and deflects an alignment switch of console <NUM>. One or more alignment switches may be used; preferably two alignment switches are employed with a cassette receptacle on console <NUM>. The alignment switch may be a pin/flag, optical, magnetic, or any other detection mechanism known in the art.

In certain embodiment, the present disclosure provides a plurality of techniques for detecting the use and/or depletion of an irrigation source. As will be discussed in greater detail below, one exemplary technique comprises the utilization of time and flow processing, where depletion is measured based on an initial volume and an approximate use of irrigation fluid over time. Another exemplary technique comprises the use of optical or resistive flow detection, where irrigation fluid depletion is calculated through optical and/or resistive sensors. In another exemplary technique, gravimetric detection may be utilized, where depletion is measured based on an initial volume and the weight of the irrigation fluid source or waste over time. In a still further exemplary technique, pressure detection may be utilized to measure depletion based on pressure exerted by the irrigation fluid upon a pressure sensor.

The detection of irrigation fluid is somewhat unique in that the solution itself is formulated such that very few or preferably none of the components within the solution are foreign to a human eye, and thus should have no pharmacological action. A typical irrigation solution may comprise a balanced salt solution, which is a sterile intraocular irrigating solution for use during intraocular surgical procedures, including those requiring a relatively long intraocular perfusion time (e.g., pars plana vitrectomy, phacoemulsification, extracapsular cataract extraction/lens aspiration, anterior segment reconstruction, etc.). As the solution typically will not contain preservatives, it is usually prepared just prior to use in surgery.

An exemplary irrigation solution mix may comprise two parts, where Part I comprises a sterile solution in a single-dose bottle to which the Part II concentrate is added. For example, a <NUM> single-dose bottle may comprise a sterile <NUM> solution. The Part I solution may contain: sodium chloride, potassium chloride, dibasic sodium phosphate, sodium bicarbonate, hydrochloric acid and/or sodium hydroxide (to adjust pH), in water for injection. For a <NUM> single dose bottle, exemplary amounts may comprise <NUM> sodium chloride, <NUM> potassium chloride, <NUM> dibasic sodium phosphate, and <NUM> sodium bicarbonate.

Part II may be a sterile concentrate in a single-dose vial for addition to Part I. Continuing with the example directed to the <NUM> single-dose bottle, the Part II single-dose vial may comprise <NUM> of the sterile concentrate. The Part II concentrate may comprise calcium chloride, magnesium chloride hexahydrate, dextrose, glutathione disulfide (oxidized glutathione) in water for injection. Exemplary amounts may comprise <NUM> calcium chloride dihydrate, <NUM> magnesium chloride hexahydrate, <NUM> dextrose, and <NUM> glutathione disulfide. Continuing with the example, after addition of Part II concentrate to the Part I bottle, exemplary amounts of the reconstituted product may contain sodium chloride (<NUM>), potassium chloride (<NUM>), calcium chloride dihydrate (<NUM>), magnesium chloride hexahydrate (<NUM>), dibasic sodium phosphate (<NUM>), sodium bicarbonate (<NUM>), dextrose (<NUM>), glutathione disulfide (oxidized glutathione) (<NUM>), hydrochloric acid and/or sodium hydroxide (to adjust pH), in water for injection. The reconstituted product may have a pH of approximately <NUM>. Osmolality may be approximately <NUM> mOsm.

It is understood by those skilled in the art that the above example is provided for illustrative purposes only, and that other solutions and product amounts suitable for phacoemulsification are contemplated by the present disclosure.

There are many factors that influence flow rates in a phaco machine, including IV pole height, pump speed and valving, among others. As illustrated in <FIG>, a pressure supply line <NUM> may be provided from a surgical console to at least one irrigation source <NUM>. The pressure supply line <NUM> may provide any pressure desired by the user up to a maximum available pressure, and may use air or any specific gas to provide the increase or modification in pressure in at least the irrigation source <NUM>.

Pressure supply line <NUM> may be connected to the lower end of the irrigation source <NUM> such that pressurization of the irrigation source <NUM> is accomplished by gas being delivered through the pressure supply line <NUM>, whereupon gas passes through any remaining irrigation fluid in the irrigation source <NUM> and into a pocket of gas above the irrigation fluid. Such a connection to the lower end of the irrigation source <NUM> may be made through an IV spike, for example. In this way, for example, the pressure supply line may be suitable for use with any size irrigation source.

Additionally and alternatively, pressure supply line <NUM> may terminate at the top, or highest point, within the irrigation source, to allow for the dispensing of the pressurized gas with little to no interaction with the body of the irrigation fluid within the irrigation source <NUM>. This form of delivery may decrease or eliminate the interaction of the delivered gas with the irrigation fluid, and may thus further decrease turbidity associated with the introduction of a pressurized gas.

As discussed above, delivery of irrigation fluid may occur through line <NUM>, which may begin at the lower end of the irrigation source <NUM> and may terminate at or into the surgical system controller at fluidics panel <NUM> and to handpiece <NUM>. In an embodiment of the present invention, both the pressure supply line <NUM> and the irrigation delivery line <NUM> may be in fluidic communication with the irrigation source through an IV spike. For example, the surgical system controller may include pressure fittings for each of the pressure supply line <NUM> and the irrigation delivery line <NUM>. Further, an IV spike compatible for use with two lines may be constructed to withstand the increase in pressure provided by the system, and may include valves or backflow prevention mechanisms to allow for reduction of pressure in, for example, the pressure supply line without the irrigation fluid entering the pressure supply line <NUM>.

In an embodiment of the present invention, the pressurized gas may be limited to a low pressure or low maximum available pressure, and may be constant so as to provide a stable and non-dynamic pressure to the irrigation source. For example, the pressure delivered through the pressure supply line <NUM> may be set by a regulated air source which may have a range of <NUM> to about <NUM> PSI. As would be appreciated by those skilled in the art, a maximum available pressure may be controlled electronically or through limiting the size of the pressurization device which may be, for example, a compressor. Likewise, a threshold monitoring may be performed, or a metered pressurization, for example, to limit pressure below an acceptable maximum. The pressure resulting in the delivery line may be measured within the surgical system controller and may be controlled by a user of the system, as discussed herein.

In one embodiment, the resultant pressure within the irrigation delivery line <NUM> may thus be controlled by adjusting both the height of the irrigation source <NUM> and the pressure introduced into the irrigation source <NUM> through the pressure supply line <NUM>. For example, an IV pole may be raised in conjunction with the addition of pressure into the irrigation source <NUM>, to thereby increase the overall pressure of the fluid being delivered to the surgical system controller and ultimately to the surgical site. Such a combination may allow for a more stable pressurized delivery of irrigation fluid by combining a constant minimum pressure through the pressure supply line <NUM> and dynamic pressure control through the changing of the irrigation source height. Such a blended approach may allow for more control over the pressure delivered during a surgical procedure, may reduce or eliminate unwanted pressure spikes or reduction in pressure due to vacuum buildup, and may allow for a reduced equipment zone by allowing for the use of shorter irrigation source heights, such as using a relatively short IV pole. Further, the increase of pressure which may be achievable using the present invention may provide the user with pressure sufficient to achieve a Tamponade feature if, for example, during surgery a retinal hemorrhaging arises.

An estimation of flow rate from irrigation source <NUM> may be calculated using the various factors discussed above (e.g., IV pole height, pump speed, valving, pressure). Based on a configuration of host settings for a volume of the initial irrigation source, the system may provide various levels of warnings or errors based on a volume or percentage of irrigation fluid used. One advantage of this approach is that additional hardware is not required, and thresholds for various warnings and/or errors could be set conservatively to accommodate estimation factors.

In one embodiment, a fluid sensor or arrangement of sensors may be deployed at any point, or multiple points of the system fluid delivery path. Fluid sensors may comprise level sensors (e.g., probe sensor, float sensor, magnetic sensor, resistive sensor, capacitive sensor), for sensing fluid levels in irrigation source <NUM>, or may comprise flow level sensors for sensing fluid flow through any point or points within the system. In the case of fluid level sensors, fluid levels may be detected in irrigation source <NUM>, and if a low-level fluid condition is detected, a suitable alarm or warning may be triggered.

In one embodiment, flow sensors may be utilized in one or more points within the system. Flow sensors may be advantageous in that the sensors may be integrated into the system, thus allowing conventional irrigation fluid containers to be used without modification. Furthermore, as flow sensors are dependent upon the actual use of the irrigation fluid, irrigation fluid status and advanced warnings may be provided as illustrated in <FIG>. For example, if one or more flow sensors detect a heavier flow of irrigation fluid being used during a procedure, the processor in the system may calculate a remaining use time and display <NUM> the time (e.g., "<NUM> minutes of remaining irrigation fluid supply") so that personnel can quickly determine if adjustments to the procedure may be necessary. If the irrigation fluid in use is reduced in response to the notification, the system processor may automatically update <NUM> the time accordingly (e.g., "<NUM> minutes of remaining irrigation fluid supply").

Furthermore, a general flow control panel may be provided on display <NUM> and is illustrated in one embodiment in <FIG>. Here, the various sensor flow measurements are displayed <NUM> to show irrigation flow (e.g., cc/min) and aspiration flow (cc/min). Furthermore, an inflow and outflow display may be provided, together with a fluid balance indicator <NUM>. Inflow fluid may originate in the irrigation bottle and travels from the irrigation bottle through plastic tubing, into the phaco needle (<NUM>) and finally into the anterior chamber of the eye. To create a pressure gradient, the bottle may be placed at a height above the patient. When the pinch valve is open the fluid in the bottle and tubing creates pressure in the anterior chamber. As an example, approximately <NUM> Hg pressure (above ambient atmospheric pressure) may be produced intraocular for every <NUM> (<NUM> inches) bottle height above the patient's eye. Outflow fluid may be fluid that leaves the anterior chamber. Fluid leaves through the phaco needle into the tubing and into the anterior chamber of the eye. This can be increased by increasing the aspiration flow rate. On occasion, fluid loss may occur through wound leakage.

Fluid balance may be determined from the pressure gradient and is considered "balanced" when adequate pressure is available to keep up with the outflow. This balance maintains a stable anterior chamber by keeping the pressure in the anterior chamber fairly constant. If the balance of inflow and outflow is altered, the anterior chamber can be under or over-pressurized. If under pressurized this can lead to shallowing and/or collapse on the anterior chamber. This will cause forward movement of the iris, lens and posterior capsule. This may lead to inadvertent rupture of the posterior capsule, due to its movement towards the phaco needle. Over pressurization (bottle height too high) can cause misdirection of aqueous fluid or deepening of the anterior chamber with zonular stress. As shown in <FIG>, a pressure balance range <NUM> may be calculated and displayed, where ranges outside the range may trigger an alarm or warning.

It should be understood by those skilled in the art that the embodiments of <FIG> are just one example, and that a variety of modifications are contemplated in the present disclosure. For example, the embodiments may be combined on one screen, and may be further combined with other displays relating to system operation or system parameters. The graphical displays may be provided in any format, such as bar graphs, pie graphs, charts, line plots etc., and may be part of a system "dashboard" displaying flow parameters.

In one embodiment, one or more electrical fluid sensors may be used, where sensor connection points may be at any or all points in an irrigation fluid path. Exemplary sensor connection points include (<NUM>) between irrigation source <NUM> and drip chamber spike <NUM>, (<NUM>) integrated into tubing cassette <NUM> and fluidics panel <NUM>, (<NUM>) between handpiece irrigation line <NUM> and handpiece <NUM>, (<NUM>) between handpiece <NUM> and handpiece aspiration line <NUM>, and/or (<NUM>) between fluidics panel <NUM> and waste collection bag <NUM>.

It should be noted that careful consideration should be had for sensor connections from handpiece <NUM> to waste collection bag <NUM>, as aspiration flow may not be consistent, and/or may experience fluid loss during a surgical procedure. Nevertheless, these general inconsistencies may be compensated for by having the system continuously monitor aspiration flows together with irrigation flows. By calculating an average differential between aspiration and irrigation flows, a weighted flow value may be calculated and applied to the aspirational flow to ensure relative consistency. Such a configuration may be advantageous, for example, to determine circumstances or procedures that may experience heavy fluid loss or other anomalies in the aspiration flow.

In one exemplary embodiment, one or more optical fluid sensors may be utilized at any or all points in an irrigation fluid path. Exemplary optical sensor connection points include, (<NUM>) proximate to irrigation source <NUM>, (<NUM>) proximate to drip chamber spike <NUM>. (<NUM>) proximate to irrigation tubing between drip chamber spike <NUM> and tubing cassette <NUM>, (<NUM>) integrated into tubing cassette <NUM> and fluidics panel <NUM>, (<NUM>) proximate to handpiece irrigation line <NUM>, (<NUM>) proximate to handpiece aspiration line <NUM>, and/or (<NUM>) proximate to waste collection bag <NUM>.

Similar to electrical fluid sensors, careful consideration should be had for optical sensor connection from handpiece <NUM> to waste collection bag <NUM>, as aspiration flow may not be consistent, and/or may experience fluid loss during a surgical procedure. Accordingly, similar monitoring of aspiration flows together with irrigation flows may be enabled to calculate a weighted differential as described above.

In another exemplary embodiment, gravimetric sensors may be utilized to detect fluid. Based on an initial weight and volume of fluid, subsequent volume may be detected by sampling weight of an irrigation source during use. For example, at an irrigation solution of <NUM> grams of salt per liter, a liter of fluid would weight approximately <NUM>,<NUM> grams. Accordingly, a <NUM> bottle would contain <NUM> grams or <NUM> ounces of saline solution. In this example, a load cell or similar weighing device may be mounted on an IV pole hanger (<NUM>) such that an irrigation fluid container would be suspended from the weighing device. The weighing device is preferably configured to communicate via wired or wireless communication to the system. As a depletion of fluid would result in a decrease in weight of the irrigation fluid, these sensed values may be utilized by the system to calculate overall irrigation fluid depletion.

Alternately, the load cell or weighing device may be mounted in fluidics panel <NUM> to weigh the contents of waste collection bag <NUM>. In this example, the increase in weight for the waste collection bag would indicate a level of fluid depletion. As was discussed above, fluid received in waste collection bag <NUM> may not necessarily correlate exactly to the fluid initially contained in the irrigation container. Accordingly, the system processor may be programmed to apply a weight to the waste collection bag measurement value to more accurately determine irrigation fluid depletion. In another embodiment, measurements may be taken from both the irrigation source and the waste bag to increase accuracy and provide a fault-tolerant system that accounts for fluid leakage.

In another exemplary embodiment, pressure sensors may be utilized to detect fluid depletion by measuring/sensing the fluid pressure exerted upon a sensor. Based on the height of an IV pole hanger, the fluid height may exert a given pressure that may decrease proportionately to the height of the fluid remaining. A pressure sensor inside fluidics panel <NUM> may be used to estimate a head height of the remaining fluid.

<FIG> illustrates an exemplary block diagram embodying any of the examples provided herein, wherein volume/flow from an irrigation source <NUM> is sensed in a sensor <NUM>, where sensed values or readings are provided to processor <NUM>, which may be a surgical device processor. Processor <NUM> is configured to perform various fluidics and/or volumetric processing, and forwards processed results for presentation on display <NUM>. Additionally, processor <NUM> may be configured to generate warnings and alarms commensurate with the processed data.

<FIG> illustrates a multi-sensor arrangement in one embodiment, where sensor measurements <NUM> and <NUM> are provided to a processor for flow/volume processing and calculation <NUM>. Processed readings may further be subjected to threshold comparison <NUM> in the processor to determine if sensor readings are within acceptable, predetermined, limits. If readings are determined to be outside predetermined limits an output signal (OUT) may be generated to indicate an alert or warning.

Those of ordinary skill in the art may recognize that many modifications and variations of the herein disclosed systems may be implemented.

For example, multiple different sensors may be applied in detecting fluid depletion. Additionally, the applications disclosed herein are not necessarily limited strictly to phacoemulsification processes, but may be applied to pressurized infusion ophthalmic surgery, and other similar surgeries as well. Other applications may include medical applications, such as an interlock between an irrigation fluid source and power delivered to a drill, saw, laser or other surgical, procedural or dental device, and/or detection of fluid delivery in a therapeutic device (e.g., cooling or warming device). Further applications include petro-chemical applications, such as detecting of product delivery interruption in a pipeline or other fluid delivery system, or interlock between a fluid source and the power delivered to a pump or motor.

Claim 1:
A surgical system, comprising:
a surgical console (<NUM>) comprising a display (<NUM>, <NUM>);
a processor (<NUM>) operatively coupled to the surgical console (<NUM>);
a surgical cassette (<NUM>) in fluid communication with an irrigation source (<NUM>, <NUM>) and an aspiration line (<NUM>), the surgical cassette comprising a reservoir (<NUM>);
wherein the processor (<NUM>) is configured to:
receive sensed measurements regarding a rate of fluid flow over time from the irrigation source (<NUM>, <NUM>),
process the rate of fluid flow relative to an initial volume of the irrigation source to determine a volume of fluid in the irrigation source, and
produce a first signal for the display (<NUM>, <NUM>) to indicate a remaining capacity of the volume of fluid,
wherein the processor (<NUM>) is configured to receive sensed measurements regarding a rate of fluid flow over time from the aspiration line (<NUM>), process the rate of fluid flow from the aspiration line (<NUM>) relative to the rate of fluid flow from the irrigation source (<NUM>, <NUM>) and produce a second signal for the display (<NUM>, <NUM>) to indicate the processed aspiration fluid flow relative to the irrigation fluid flow,
wherein the processor (<NUM>) is configured to process the rate of fluid flow from the aspiration line (<NUM>) by applying a weight to the sensed measurements regarding a rate of fluid flow over time from the aspiration line (<NUM>), wherein a weighted flow value is calculated and applied to the aspiration flow by calculating an average differential between aspiration and irrigation flows,
characterized in that the surgical system further comprises a vacuum pump arrangement (<NUM>) comprising a pump (<NUM>) and a pressure regulator (<NUM>), wherein the vacuum pump arrangement is connected to the reservoir via a fluid pathway and is configured to add air to the reservoir and remove air from the reservoir.