Patent Publication Number: US-2003225359-A1

Title: System and method for enhancing oxygen content of infusion/irrigation fluid for ophthalmic surgery

Description:
BACKGROUND  
       [0001] 1. Field of the Invention  
       [0002] The present invention generally relates to ophthalmic surgery. More particularly, the invention relates to systems for maximizing the oxygen content of infusion/irrigation fluids used in ophthalmic surgical procedures, and to methods for using the same.  
       [0003] 2. Background  
       [0004] The use of infusion/irrigation fluids during the course of ophthalmic surgical procedures is well known. These fluids provide structural support and fluidic balance that keep the eye inflated during the manipulation and/or removal of tissue from within the eye.  
       [0005] It also is know in the art that invasive surgical procedures can negatively effect ocular tissue at the cellular level. For example, representative of the complications which can arise as a result of invasive ophthalmic surgical procedures are both the opacification of ocular tissues, and a reduction in the functionality and sensitivity of those tissues.  
       [0006] Further, it is well understood by those in the art that intraocular infusing/irrigating solutions can have adverse effects upon ocular morphology and function. Indeed, significant effort has been expended in the search for an optimal chemical composition for use as an intraocular infusion/irrigating solution. More specifically, the goal of this effort has been (and is) to find a chemical composition that produces minimal negative effects upon the cellular structures of the eye, while at the same time, maximizing the patient&#39;s post-operative visual acuity. This effort has been successful to the extent in that some infusion fluids have been found to be less harmful to ocular anatomy and physiology than others. Nevertheless, a need still exists for an intraocular infusion/irrigation solution that will further minimize the negative effects of ophthalmic surgical stress.  
       SUMMARY OF THE INVENTION  
       [0007] The present invention provides an infusion/irrigation fluid administration system and method that maximizes the quantity of oxygen provided to the tissue of the eye during the course of ophthalmic surgical procedures.  
       [0008] In preferred embodiments, the invention includes a system that highly oxygenates the infusion/irrigation fluid used during the course of ophthalmic surgery substantially immediately prior to its introduction to the eye.  
       [0009] Addition of oxygen to infusion or irrigation fluid (i.e. infusion/irrigation fluid) can have a significantly positive effect to tissue affected by surgery, particularly in ophthalmic surgery. Accordingly, use of oxygenated fluids in accordance with the invention can positively impact potential surgical trauma particularly ophthalmic surgery, recovery from surgical procedures particularly ophthalmic surgery, and the like.  
       [0010] More particularly, in one preferred embodiment of the invention, an in-line, oxygenating chamber is provided in the infusion/irrigation fluid line between a fluid source and the infusion/irrigation site. Typically, the oxygenation chamber is located close to the operative site. This oxygenating chamber generally contains a gas permeable member (preferably diffusing member) that is supplied by an oxygen source. More specifically, the fluid flowing through the infusion/irrigation line is passed through the oxygenation chamber wherein oxygen travels through a gas permeable membrane or the like defining at least a portion of the diffusing gas permeable member, and diffuses into the fluid. This results in the provision of hyperoxic fluid directly to the ophthalmic surgical site.  
       [0011] In another preferred embodiment, an alternative oxygenating infusion/irrigation fluid administration system is provided. This system generally includes a fluid source; an I.V. administration spike; fluid tubing; atmospheric air vent tubing with a filter; a pressurized oxygen canister or lecture bottle; and appropriate adaptive connectors. In addition, the system may also optionally include a stopcock. In this embodiment, the oxygen is bubbled through the fluid in the source. Then the fluid is allowed to pass through the tubing to the operative site.  
       [0012] The invention can be employed with a wide variety of surgical procedures for delivery of fluid to a surgical site. However, the invention is particularly useful for delivery of oxygenated fluid to an opththalmic surgical site (e.g. to or proximate to a patient&#39;s eye), such as by infusing the oxygenated fluid into a patient&#39;s eye. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013] These, and other features and advantages of the invention, will become clear to those skilled in the art from the following detailed description of the preferred embodiments of the invention rendered in conjunction with the appended drawings in which like reference numerals refer to like elements throughout, and in which:  
     [0014]FIG. 1 is an illustrative, diagrammatic view showing an oxygenation unit located in an infusion/irrigation fluid line close to the eye, and sources of infusion/irrigation fluid and oxygen associated therewith; and,  
     [0015]FIG. 2 is an illustrative, diagrammatic view of another infusion/irrigation fluid oxygenation system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0016] Referring now to the drawings, and particularly to FIG. 1, there is shown an illustrative, diagrammatic view of one preferred embodiment of the invention. In this embodiment, a fluid tube, generally indicated at  10 , extends from a fluid source  15  to the eye  20  of the patient. An in line, oxygenating chamber, generally indicated at  25 , is provided in the fluid line  10  close to the ophthalmic surgical site, generally indicated at  26 .  
     [0017] The oxygenating chamber  25  includes a substantially totally enclosed, hollow, outer body  27  containing a diffusing gas permeable member  30 . The interior of body  27  is supplied with infusion/irrigation fluid through line  10   a,  and diffusing gas permeable member  30  is supplied by a pressurized oxygen source  35  through tubing, generally indicated at  36 . The interior of body  27  also is connected to the ophthalmic surgical site by tubing, generally indicated at  10   b.    
     [0018] More specifically, the oxygenating chamber  25  includes outer body  27  defining an internal volume  29 , and end ports  45  and  46  connected to the lumens  47  and  48  of input and output connectors  49  and  50 , respectively. In the particular embodiment shown, connectors  49  and  50  extend outwardly from opposite ends of cylindrical, outer, hollow body  27 . Outer body  27 , for example, may be approximately four (4) inches long and approximately 0.75 inches in diameter. It is to be understood, however, that other shapes and dimensions are contemplated to be within the scope of this invention in its broadest aspects.  
     [0019] Diffusing gas permeable member  30  may be substantially cylindrical, and is formed (at least in part) of a gas permeable membrane or other gas permeable material. In the embodiment shown in the drawing, diffusing gas permeable member  30  is a hollow, cylindrical element slightly shorter than body  27 , and encloses an internal substantially cylindrical volume  31 . Again, it is to be understood that the dimensions and shape of the diffusing gas permeable member  30  may be other than cylindrical without departure from the present invention in its broadest aspects. Indeed, since a goal of the invention is to highly oxygenate the infusion/irrigation fluid, the greater the area of contact between the gas permeable portion of member  30  and the interior volume  29  of chamber  25  is, the better the diffusion of oxygen into the fluid will become. Accordingly, not only does the shape of member  30  not have to be cylindrical, but also, as shown in phantom at  33  in FIG. 1, member  30  may be made up of a plurality of hollow elements  31  extending in the direction of fluid flow between manifolds  35   a  and  35   b.  A port  52  at one end of the member  30  connects the internal volume  31  of the member  30  to the lumen  54  of a connection member  56  that extends from the member  30  through an end of the body  27 .  
     [0020] A gas transfer tube  36  connects pressurized oxygen source  35  to connector  56  such that oxygen under pressure may be provided to the interior of volume  31  of member  30 . In addition, a stopcock  60  may be provided around line  10 b for limiting the flow of infusion/irrigation fluid to the ophthalmic surgical site  26 .  
     [0021] All of the above referred to connections are fluid tight to prevent gas and/or infusion/irrigation fluid leakage. For example, the gas transfer tubing  36  might fit tightly over a connector  56  provided with an enlarged outer end (not shown). In such a case, the tubing  36  may be held in place by a screw or spring clamp (not shown) engaging the outer surface of the tubing between the end of body  27  and the enlarged end of connector  56 . Similarly, the outer ends of fluid connectors  49  and  50  may be sized to tightly exteriorly receive ends of infusion tubing  10 . Further, the material of the connectors may be chosen such that spring or screw clamps may be utilized without breakage thereof and/or the connectors may be crimped against the end of an infusion/irrigation fluid tube inserted therein.  
     [0022] In this way, a system is provided wherein infusion/irrigation fluid flowing through an infusion line to an ophthalmic surgical site is passed through an in line oxygenation chamber. As the infusion fluid flows through the chamber, oxygen passes through a gas permeable portion of an element located internally of the chamber, and diffuses into the fluid. This results in the desired provision of hyperoxic infusion irrigation fluid directly the ophthalmic surgical site.  
     [0023] As discussed above, preferably the fluid is oxygenated substantially immediately prior to delivery of the oxygenated fluid to an ophthalmic surgical site, such as delivery to a patient&#39;s eye or proximate thereto where surgery is being performed. “Oxygenation substantially immediately prior to delivery of the fluid” is recognized herein as indicating that the fluid has been oxygenated at least the same day (within 24 hours) as fluid application, more typically within about 6, 5, 4, 3, 2, 1, 0.5 or 0.25 hours prior to fluid delivery to a surgical site. Particularly preferred is where the fluid is delivered to a surgical site within about 5, 4, 3, 2, 1, or about 0.5 minutes after oxygenation treatment. A preferred system is where the oxygenation is performed in the fluid flow path from the fluid source to the delivery surgical site. The in-line oxygenation system depicted in the figures exemplifies such flow-path oxygenation.  
     [0024] Further, oxygenation treatment of a fluid in accordance with the present invention preferably increases the oxygen content of the fluid by at least about 0.5, 1, 2 or 3 molar percent, relative to the oxygen content of the fluid without the oxygenation treatment, and more preferably the oxygen content of the fluid is increased by at least about 4, 5, 6, 7, 8, 9, or 10 mole percent, relative to the oxygen content of the fluid without the oxygenation treatment.  
     [0025] Additionally, references herein to oxygenating a fluid indicate that the fluid is exposed to oxygen, which exposure can be by performed by a wide variety of methods. While the bubbling oxygen through a fluid particularly as exemplified herein is a generally preferred oxygenation treatment, other procedures also may be suitably employed.  
     [0026] In an alternative embodiment of the invention, illustratively depicted in FIG. 2, the system is generally indicated at  200 . The system generally includes (i) an infusion/irrigation fluid container  201 ; (ii) an I.V. administration spike  205 ; (iii) fluid infusion tubing  210 ; (iv) atmospheric air vent spike/tubing  215  with a filter  220 ; (v) a pressurized oxygen canister or lecture bottle  225 ; and (vi) appropriate adaptive connectors, such as drip chamber  226 , and fluid container closure member  227 . In addition, the system also may optionally include a stopcock  230 .  
     [0027] The administration spike  205  is adapted to penetrate the fluid container closure member  227  thereby providing an interface to the fluid in container  201 . In this embodiment, the infusion/irrigation fluid  232  is supplied to the ophthalmic surgical site  26  by gravity feed. Hence, it will be understood that the infusion fluid travels from the container  201  through the spike  205 , through the infusion tubing  210 , past optional stopcock  230 , to a cannula  245  that interfaces with the eye  250 . Further, administration spike  205  also includes a side connector  252  that provides an input path from the oxygen source  225  through gas line  255  to the interior of fluid container  201 .  
     [0028] The operation of the system depicted in FIG. 2 now will be discussed.  
     [0029] Oxygen is allowed to enter the administration spike  205  through connector  252  and tubing  255 , which is interfaced with the pressurized oxygen source  225 . In this regard, it should be understood that the oxygen might either travel through a separate internal lumen (not shown) within spike  205  into container  201 , or alternatively, travel upward through the same lumen through which the infusion/irrigation fluid flows downwardly toward the eye  250 . Stated slightly differently, the pressure within the airspace  260  above the fluid level  265  in the container  201  can be controlled in combination with the cross-sectional area of the infusion tubing and the volume of oxygen introduced through the interface over time. Thus, in appropriate circumstances, liquid may be allowed to flow downwardly through the tube, while, at the same time, oxygen bubbles are allowed to flow upwardly through the spike  205 . Oxygen, therefore, is caused continuously bubble up through the infusion fluid in the container  201 . As the oxygen bubbles flow upwardly through the fluid, oxygen diffuses into the fluid.  
     [0030] The vent spike  215  also penetrates the container closure  227 . However, instead of remaining close to the inner side of the closure member as the end of the administration spike  205  does, the vent spike projects into air space  260  above the fluid in container  201 . The vent spike typically includes an external filter  220  to maintain the purity of the infusion fluid. As will be seen from the drawings, the venting structure provides a continuous open passageway from air space  260  to the outside atmosphere. Accordingly, excess oxygen not diffused into the infusion/irrigation fluid does not adversely increase the pressure in the container. The result is that the oxygen content of the infusion/irrigation fluid provided to the eye is maximized (i.e., hyperoxic fluid is provided to the eye during ophthalmic surgery in a manner that provides maximum protection for the ocular tissues with which it comes in contact). The maximum post-operative visual acuity result possible as it relates to the characteristics of the infusion fluid utilized are thereby achieved.  
     [0031] It is to be understood that the foregoing specification has been presented by way of illustration only, and not limitation. Numerous alterations, changes, modifications, variations and the like will occur to those skilled in the art in view of the above described preferred embodiments of the present invention. Accordingly, the present invention is to be understood as being limited only by the terms of the claims appended hereto.