Abstract:
The present invention relates generally to providing pressurized infusion of liquids and, more particularly, is directed to providing a stable and pressurized flow of irrigation fluid to the eye during surgery.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to providing pressurized infusion of liquids and, more particularly, is directed to providing a stable and pressurized flow of irrigation fluid to the eye during surgery. 
         [0003]    2. Description of the Background 
         [0004]    Certain surgical procedures, such as phacoemulsification surgery, have been successfully employed in the treatment of certain ocular problems, such as cataracts. Phacoemulsification surgery utilizes a small corneal incision to insert the tip of at least one phacoemulsification handheld surgical implement, or handpiece, through the corneal incision. The handpiece includes a needle which is ultrasonically driven once placed within the incision to emulsify the eye lens, or to break the cataract into small pieces. The broken cataract pieces or emulsified eye lens may subsequently be removed using the same handpiece, or another handpiece, in a controlled manner. The surgeon may then insert a lens implant into the eye through the incision. The incision is allowed to heal, and the result for the patient is typically significantly improved eyesight. 
         [0005]    As may be appreciated, the flow of fluid to and from a patient through a fluid infusion or extraction system, and thus the control of fluids and fluid pressure through the phacoemulsification handpiece, is critical to the procedure performed. Different medically recognized techniques have been utilized to control the fluid flow during the lens removal portion of the surgery. Among these, one popular technique is a simultaneous combination of phacoemulsification, irrigation and aspiration using a single handpiece. This method includes making the incision, inserting the handheld surgical implement to emulsify the cataract or eye lens, and, simultaneously with this emulsification, having the handpiece provide a fluid for irrigation of the emulsified lens and a vacuum for aspiration of the emulsified lens and inserted fluids. 
         [0006]    Currently available phacoemulsification systems, such as those mentioned above, typically include a variable speed peristaltic pump and/or vacuum pump, a vacuum sensor, an adjustable source of ultrasonic power, and a programmable microprocessor with operator-selected presets for controlling aspiration rate, vacuum and ultrasonic power levels. The phacoemulsification handpiece is interconnected with a control console by an electric cable for powering and controlling a piezoelectric transducer that drives the action of the handpiece. Tubing provides irrigation fluid to the eye through the handpiece and enables withdrawal of aspiration fluid from an eye through the handpiece. 
         [0007]    Generally, irrigation and aspiration are employed by the surgeon using the device to remove unwanted tissue and maintain pressure within the eye. Moreover, the use of, and particularly the pressurization of, the irrigation fluid is critical and may, for example, prevent the collapse of the eye during the removal of the emulsified lens. Irrigation fluid pressure is also used to protect the eye from the heat generated by the ultrasonic cutting needle and may suspend fragments created during the surgery in fluid for more easy removal through aspiration. 
         [0008]    Irrigation fluid pressure has been conventionally handled in two ways. The first method to increase irrigation fluid pressure has relied upon the height of the fluid source. Conventional IV poles may be adjusted in height to create the desired pressure head using gravity-feed principles. The second method includes the use of an infusion pump either directly pumping the fluid typically in the form of a peristaltic pump used in-line with an irrigation delivery line or by pressurizing the fluid container thus increasing higher atmosphere above the fluid resulting in higher infusion pressure and flow to the surgical site. 
         [0009]    Although each of the foregoing methods produces pressurized irrigation fluid at the surgical site, each suffers from difficulties in maintaining a constant pressure. For example, infusion pumps must be deployed with a dynamic pressure-sensing control loop to prevent over or under pressurizing the anterior chamber, and may further require venting to control unwanted pressures. Solving these issues may require the use of a special drip spike, a mechanical pressurization compartment, or an over-bag, to control atmospheric pressure. Such solutions add costs and complications to the surgical set-up and to the maintenance of the surgical equipment. 
         [0010]    Further, it is typical that the smaller the incision made during surgery, the greater the pressure needed to properly irrigate the surgical site, and gravity-feed systems may not produce the desired amount of pressure due at least to limitations on the height which may be achieved by physically raising the source of irrigation liquid. Typically, the irrigation source is affixed to a movable IV pole which is raised to increase the pressure head. Of course, limitations as to the maximum height of the IV pole and/or the height of overhead objects, such as lights or a ceiling, for example, may limit the amount of achievable height. 
         [0011]    Thus, there is a need for a system and method that provides improved pressurized delivery of irrigation fluid to a surgical site. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention is and includes a system and a method of providing pressurized fluid to the eye. The system and method may include at least one constant pressure source and at least one height adjustable irrigation fluid source to provide a stable pressurized fluid flow. 
         [0013]    Accordingly, the disclosure provides a system and method that provides improved pressurized delivery of irrigation fluid to a surgical site. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0014]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. 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. 
           [0015]    In the drawings: 
           [0016]      FIG. 1  illustrates an embodiment of the pressurized infusion apparatus of the present invention; 
           [0017]      FIG. 2  illustrates an embodiment of the graphical user interface of the present invention; 
           [0018]      FIG. 3  illustrates an embodiment of the graphical user interface of the present invention; and 
           [0019]      FIG. 4  illustrates an embodiment of the graphical user interface of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    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. 
         [0021]    In an embodiment of the present invention, a pressurized line  140  is provided to an irrigation source  110 , such as an IV bag/bottle, to increase the pressure within the irrigation source. This pressurization may be adjustable to maintain or increase irrigation pressure as needed, such as where sufficient height is unavailable to provide the necessary gravitationally forced pressure. 
         [0022]    As illustrated in  FIG. 1 , a pressure supply line  140  may be provided from a surgical console  160  to at least one irrigation source  110 . The pressure supply line  140  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  110 . The irrigation source  110  may be in the form of an IV bag, for example, or may be or include any vessel used to hold irrigation fluid. 
         [0023]    The pressure supply line  140  may be connected to the lower end of the irrigation source  110  such that pressurization of the irrigation source  110  is accomplished by the gas being delivered through the pressure supply line  140 , whereupon the gas passes through any remaining irrigation fluid in the irrigation source  110  and into a pocket of gas above the irrigation fluid. Such a connection to the lower end of the irrigation source  110  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. 
         [0024]    Additionally and alternatively, the pressure supply line  140  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  110 . 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. 
         [0025]    Delivery of irrigation fluid may occur through a second line  150 , which may begin at the lower end of the irrigation source  110  and may terminate at or into the surgical system controller  160 . In an embodiment of the present invention, both the pressure supply line  140  and the irrigation delivery line  150  may be in fluidic communication with the irrigation source  110  through an IV spike. For example, the surgical system controller  160  may include pressure fittings for each of the pressure supply line  140  and the irrigation delivery line  150 . 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  150 . 
         [0026]    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  140  may be set by a regulated air source which may have a range of 0 to about 5 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  100 , as discussed herein. 
         [0027]    In an embodiment of the present invention, the resultant pressure within the irrigation delivery line  150  may thus be controlled by adjusting both the height of the irrigation source  110  and the pressure introduced into the irrigation source  110  through the pressure supply line  140 . For example, an IV pole  130  may be raised in conjunction with the addition of pressure into the irrigation source  110 , to thereby increase the overall pressure of the fluid being delivered to the surgical system controller  160  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  140  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. 
         [0028]    In addition to the use of standard irrigation fluid sources such as, for example, IV bags/bottles, the present invention may also be suitable for use with other pressure delivery means, such as, for example, mechanically pressurized bags which may be equipped with a pressure transducer. Similarly, an irrigation source may be pre-pressurized (with the system allowing for a drop in pressure as the contents of the irrigation fluid are expelled). For example, as the pressure drops in a pre-pressurized irrigation fluid source, the height of the irrigation fluid source may be raised (either automatically or by indication to the graphical user interface discussed herein) to compensate and/or achieve the desired pressure. The height of the irrigation fluid source may be raised or lowered manually or using motorized means suitable for controlling the height and weight of such a pole. 
         [0029]    The present invention may display the irrigation fluid pressure of the system on a graphical user interface (GUI) associated with the surgical system controller and utilized through a touchscreen interface, for example. The GUI  200  may allow for the user to select, for example, an initial height of the irrigation source and/or may alert the user to the maximum and minimum heights achievable with the system. For example, as illustrated in  FIG. 2 , the system may allow for IV poles of various sizes and may be calibrated in regard to the maximum and minimum heights possible. Similarly, a middle or optimum height may be displayed for selection. Further, a use may select a predetermined height using one of buttons  201 ,  202 , and/or  203 . Such an optimal height may be, for example, a height at which a technician can easily access the irrigation source and which will also allow the system to provide the desired range of pressure. 
         [0030]    As further illustrated in  FIG. 2 , the GUI may present the user with options such as, for example, choosing the units of measurement used by the system. The height of the irrigation source may be selected to be displayed in inches using button  210  or centimeters using button  211  and may be converted into terms more common to a specific type of surgery. For example, when using the present invention in relation to an eye surgery, the pressure created by the height of the irrigation fluid may be translated into a more standard intraocular pressure (IOP) reading, in terms such as mmHg. 
         [0031]    In an embodiment of the present invention, the pressure reading provided through the GUI may be indicative of the total pressure of the irrigation delivery line, and may combine measurements of both the irrigation source height and the pressure provided into the pressure supply line. In this way, for example, the GUI may provide both an actual pressure reading based on direct measurement of the irrigation supply line, and a target or desired pressure based on the height of the irrigation fluid source and the pressure provided through the pressure supply line, if any. 
         [0032]    As illustrated in  FIG. 3 , the GUI  200  may allow the user to adjust the pressure in the irrigation supply line by adjusting the height of the irrigation fluid source using buttons  310  and/or  311 . The user may incrementally change the height, such as preferably altering the height in 1 cm increments. Further, the system may provide the user with certain preset pressure selections, which may respectively correlate to defined heights of the irrigation fluid source. For example, defined pressures may be given in 15 cm increments and may, for example, be given for heights such as 15 cm, 30 cm, 45 cm, and the like (not shown). Although any stepwise value may be used, the present invention may provide such predefined pressure heights to allow for ease of use and calibration of the system. 
         [0033]    In a particular exemplary embodiment, the GUI  200  may provide a series of single-touch controls, for which an irrigation height of 30 cm may be one. If selected, the predefined pressure may be expected to be a certain value, “X”. If this value is not the value actually measured by the system in the pressure supply line, the system may reconfigure the assumed height value for the irrigation source, and/or may adjust the amount of secondary pressure being delivered into the pressure supply line. 
         [0034]    As illustrated in  FIG. 4 , for example, the GUI  200  of the present invention may allow for the calibration and priming of the irrigating pressure. The GUI  200  may provide a time estimate for such calibration and may also provide the user with total irrigation source height information. By way of non-limiting example only, the GUI  200  may alert the user to a maximum height of 91+cm, which may be the total of the IV pole height (76 cm) and additional height by installation of an extension (15 cm). 
         [0035]    The GUI  200  may also provide other options for the user, such as, for example, allowing for canceling priming and tuning by selecting button  410 , for example. Button  411  may allow the user initiate priming and tuning of the system while the Bypass Prime button  412  may allow for the priming feature to be passed over or aborted, for example. Button  413  may allow for tuning of the phaco handpiece and button  414  may allow a user to return to the Main Menu. 
         [0036]    Those of ordinary skill in the art may recognize that many modifications and variations of the herein disclosed systems and methods may be implemented without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers such modifications and variations provided they come within the scope the appended claims and their equivalents.