Medical valve with positive flow characteristics

Abstract

A valve for selectively permitting a fluid flow between first and second medical implements is disclosed. The valve has a housing with an interface suitable for receiving a connector portion of a first medical device such as a catheter, and a seal made of a flexible material. The seal has a first end in fluid communication with the interface, a second end suitable for receiving the second medical device, and at least one slit in fluid communication with the first end and the second end. The slit defines a restricted fluid flow path and a relatively small interior volume when in an undisturbed state, defines an expanded fluid flow path and a larger interior volume upon the introduction of the second medical instrument into the slit, and retracts to define a restricted flow path and a small interior volume upon the withdrawal of the second medical device from the seal. The slit is constructed such that its upstream end initially is sealed as the second medical device is withdrawn. A fluid occupying the small interior volume of the slit is forced toward the downstream end of the slit.

What is claimed is:  
     
         1 . A medical valve for selectively permitting fluid to flow between a first medical device and a second medical device, the valve comprising: 
 a housing having an interface suitable for receiving a connector portion of the first medical device; and    a seal made of a flexible material, the seal having a downstream end in fluid communication with the interface, an upstream end suitable for receiving the second medical device, and a normally substantially closed passage in fluid communication with the downstream end and the upstream end, the passage having a relatively small interior volume when in an undisturbed state and a larger interior volume upon the introduction of the second medical device into the upstream end of the passage, the passage retracting to define a restricted flow path and a relatively small interior volume upon the withdrawal of the second medical device from the seal, the upstream end initially being sealed as the second medical device is withdrawn, so that a fluid occupying the interior volume is forced toward the downstream end as the passage walls collapse.    
     
     
         2 . The medical valve defined in  claim 1 , wherein the slit has a region of minimum width that maintains substantially fluid-tight contact against substantially the entire perimeter of the second medical device at an area near the upstream end of the seal.  
     
     
         3 . The medical valve defined in  claim 1 , wherein the seal comprises: 
 a body made of flexible material and having a downstream end and an upstream end opposite the downstream end, the downstream and upstream ends of the body being oriented to correspond to the downstream and upstream ends of the seal;    a lead lumen formed in the downstream end of the body and in fluid communication with the passage;    a neck formed at the second end of the body; and    a transverse flange at an end of the neck opposite the body, the transverse flange having at least one opening in fluid communication with the passage.    
     
     
         4 . The medical valve defined in  claim 29 , wherein the lead lumen is centered on an axis substantially parallel to or collinear with a longitudinal axis of the seal.  
     
     
         5 . The medical valve defined in  claim 29 , wherein the seal body comprises a substantially rectangular slab of flexible material and the neck is coplanar with the body.  
     
     
         6 . The medical valve defined in  claim 29 , wherein the passage comprises a slit and the passage opening comprises a slit opening.  
     
     
         7 . The medical valve defined in  claim 32 , wherein the slit comprises: 
 a relatively thin, substantially planar channel having a varying width;    a region of minimum width; and    a region of larger width on a side of the region of minimum width remote from the slit opening;    wherein the width of the slit tapers from the slit opening to the region of minimum width.    
     
     
         8 . The medical valve defined in  claim 29 , wherein the seal body has first and second lateral portions and the housing further comprises: 
 a seal holder attached to the interface, the seal holder comprising a hollow cylindrical member that extends from the interface and has an axial opening opposite the interface, and first and second side openings;    a lead cannula attached to and in fluid communication with the interface and extending from the interface toward the axial opening, the lead cannula being centered on an axis substantially parallel to or collinear with a longitudinal axis of the housing;    wherein the seal is disposed within the seal holder such that the lead cannula extends at least partially into the lead lumen, the flange extends across the axial opening, and the first and second lateral portions of the seal body extend into the first and second side openings.    
     
     
         9 . The medical valve defined in  claim 8 , wherein the first and second side openings have top edges that define the portions of the side openings nearest the axial opening, and the first and second lateral portions of the seal body have shoulders that define the extent of the lateral portions nearest the transverse flange, and the top edges of the side openings are sufficiently remote from the axial opening to impart a tensile force to the seal between the transverse flange and the shoulders, thereby causing the perimeter of the transverse flange to bear against the edges of the axial opening and the transverse flange to take on a concave configuration with the slit opening near the deepest portion of the concavity.  
     
     
         10 . The medical valve defined in  claim 8 , wherein at least a portion of the lead cannula is disposed within the lead lumen when the seal is in an undisturbed state and at least a portion of the lead cannula enters the region of the slit nearest the lead lumen upon axial compression of the seal occurring when the second medical device is inserted into the seal.  
     
     
         11 . A valve seal for use in a medical valve having an interface for fluid communication with a first medical device, the seal comprising: 
 a first end in fluid communication with the interface, a second end suitable for receiving a second medical device, and at least one slit in fluid communication with the first end and the second end, wherein the slit defines a restricted fluid flow path and a relatively small interior volume when in an undisturbed state, defines an expanded fluid flow path and a larger interior volume upon the introduction of the second medical device into the slit, and retracts to define a restricted flow path and a relatively small interior volume upon the withdrawal of the second medical device from the seal.    
     
     
         12 . The valve seal defined in  claim 11 , wherein the slit has a region that maintains substantially fluid-tight contact against substantially the entire perimeter of the second medical device at an area near the second end of the seal.  
     
     
         13 . The valve seal defined in  claim 11 , further comprising: 
 a body made of flexible material and having a first end and a second end opposite the first end, the first and second ends of the body being oriented to correspond to the first and second ends of the seal;    a lead lumen formed in the first end of the body, the lead lumen being centered on an axis substantially parallel to or collinear with a longitudinal axis of the seal;    a neck formed at the second end of the body,    a transverse flange at an end of the neck opposite the body, the transverse flange having at least one slit opening; and    at least one slit formed within the seal, the slit being in fluid communication with the lead lumen and the slit opening.    
     
     
         14 . A method of causing a positive flow in the direction of a first medical device from a valve that connects the first medical device to a second medical device and has an associated seal, the seal being adapted to receive at least a portion of the second medical device and provide fluid communication between the first and second medical devices, the method comprising the steps of: 
 withdrawing the second medical device from the seal; and    permitting the seal to retract from a large interior volume to a relatively small interior volume so as to displace any fluid within the seal in the direction of the first medical device.    
     
     
         15 . A method of preventing blood from flowing out of a patient into a catheter when a syringe is withdrawn from a valve between the syringe and the catheter, the method comprising the steps of: 
 connecting the downstream end of the valve to the catheter;    inserting the end of the syringe into a slit forming the upstream end of a normally substantially closed seal passage that is located in a resilient seal and is in fluid communication with the downstream end of the valve, thereby causing the seal passage to open while providing sealing contact between the syringe and the upstream end of the seal passage;    injecting fluid from the syringe through the seal passage to the catheter and into the patient; and    withdrawing the syringe, allowing the walls of the seal passage to return to their substantially closed position while initially maintaining sealing contact between the upstream end and the syringe to thereby provide a force urging fluid in the passage toward the catheter.    
     
     
         16 . The method defined in  claim 15 , wherein the step of inserting the end of the syringe into the slit includes axially compressing the seal.  
     
     
         17 . A medical valve for selectively permitting fluid to flow between a first medical device and a second medical device through an associated seal, the valve comprising: 
 an interface suitable for receiving a connector portion of the first medical device; and    a seal holder in fluid communication with the interface.    
     
     
         18 . A system for administering fluid to a blood vessel of a patient, the system comprising: 
 a catheter having an upstream end and a downstream end that is suitable for placement in fluid communication with the blood vessel;    a syringe suitable for expelling fluid into the catheter; and    a valve having a fitting suitable for connection to the upstream end of the catheter and providing selective fluid communication between the syringe and the catheter, the valve further comprising: 
 a seal made of a flexible material, the seal having a downstream end in fluid communication with the fitting, an upstream end suitable for receiving the syringe, and a normally substantially closed passage in fluid communication with the downstream end and the upstream end, the passage having a relatively small interior volume when in an undisturbed state and a larger interior volume upon the introduction of the syringe into the upstream end of the passage, the passage retracting to define a restricted flow path and a relatively small interior volume upon the withdrawal of the second medical device from the seal, the upstream end initially being sealed as the syringe is withdrawn, so that a fluid occupying the interior volume is forced toward the downstream end as the passage walls collapse.  
   
     
     
         19 . A method of making a medical valve seal of the type having a body made of a flexible material and a slit formed within the body between adjacent first and second slit walls, the method comprising: 
 molding first and second preforms, each comprising one of said first and second slit walls and a perimeter edge portion;    pressing said first and second preforms together so that said first and second slit walls face each other; and    molding an additional amount of a flexible material to at least part of said perimeter edge portions of said first and second preforms so that said first and second preforms and said additional material form a unitary mass with said slit formed therein.    
     
     
         20 . The method of  claim 19 , wherein: 
 said first and second preforms further comprise outer face portions; and    the step of molding an additional amount of a flexible material further comprises molding said additional amount of flexible material to said outer face portions.    
     
     
         21 . The method of  claim 19 , wherein: 
 the step of pressing said first and second preforms together comprises moving first and second mold halves containing said first and second preforms together so that said first and second slit walls contact one another; and    the step of molding an additional amount of a flexible material comprises interposing an overmold plate between said first and second mold halves to define a mold cavity between (i) said mold halves, (ii) said perimeter edge portion of said preforms and (iii) an inner edge of an overmold opening in said overmold plate, and injecting said additional amount of a flexible material into said mold cavity.    
     
     
         22 . The method of  claim 19 , wherein each of said preforms further comprises a flange portion connected to a respective one of said slit walls.  
     
     
         23 . The method of  claim 21 , wherein said first and second mold halves and said overmold plate have contacting surfaces that are substantially planar.  
     
     
         24 . The method of  claim 21 , wherein said overmold plate has at least one mandrel projecting from said inner edge of said overmold opening, said mandrel forming a lead lumen in said seal when said additional amount of a flexible material is injected into said mold cavity.  
     
     
         25 . The method of  claim 21 , wherein said additional amount of a flexible material forms the remainder of said seal.  
     
     
         26 . The method of  claim 19 , wherein the step of pressing said first and second preforms together comprises applying sufficient pressure to prevent said additional amount of a flexible material from migrating between said first and second preforms.  
     
     
         27 . A catheter for establishing fluid communication between a medical device and the vasculature of a patient, said catheter comprising: 
 an elongated cannula having a proximal end, a distal end, and at least one axial lumen extending through said cannula; and    a valve for selectively opening and closing said proximal end of said cannula, said valve comprising: 
 a housing having an interface suitable for connection to said proximal end of said cannula; and  
 a seal made of a flexible material, the seal having a distal end in fluid communication with said interface, a proximal end suitable for receiving the medical device, and a normally substantially closed passage in fluid communication with the distal end and the proximal end, the passage having a relatively small interior volume when in an undisturbed state and a larger interior volume upon the introduction of the medical device into the proximal end of the passage, the passage retracting to define a restricted flow path and a relatively small interior volume upon the withdrawal of the medical device from the seal, the proximal end initially being sealed as the second medical device is withdrawn, so that a fluid occupying the interior volume is forced toward the distal end as the passage walls collapse.  
   
     
     
         28 . The catheter defined in  claim 27 , wherein said passage has a region of minimum width that maintains substantially fluid-tight contact against substantially the entire perimeter of the medical device at an area near the proximal end of the seal.  
     
     
         29 . The catheter defined in  claim 27 , wherein the seal comprises: 
 a body made of flexible material and having a distal end and a proximal end opposite the distal end, the distal and proximal ends of the body being oriented to correspond to the distal and proximal ends of the seal;    a lead lumen formed in the distal end of the body and in fluid communication with the passage;    a neck formed at the second end of the body; and    a transverse flange at an end of the neck opposite the body, the transverse flange having at least one passage opening in fluid communication with the passage.    
     
     
         30 . The catheter defined in  claim 29 , wherein the lead lumen is centered on an axis substantially parallel to or collinear with a longitudinal axis of the seal.  
     
     
         31 . The catheter defined in  claim 29 , wherein the seal body comprises a substantially rectangular slab of flexible material and the neck is coplanar with the body.  
     
     
         32 . The catheter defined in  claim 29 , wherein the passage comprises a slit and the passage opening comprises a slit opening.  
     
     
         33 . The catheter defined in  claim 32 , wherein the slit comprises: 
 a relatively thin, substantially planar channel having a varying width;    a region of minimum width; and    a region of larger width on a side of the region of minimum width remote from the slit opening;    wherein the width of the slit tapers from the slit opening to the region of minimum width.    
     
     
         34 . The catheter defined in  claim 27 , further comprising a guidewire disposed within said lumen and said seal.  
     
     
         35 . The catheter defined in  claim 27 , further comprising a connector connected to said valve.  
     
     
         36 . A catheter, comprising: 
 an elongated cannula having a proximal end, a distal end, and a lumen extending between said proximal end and said distal end, said distal end being suitable for insertion into the vasculature of a patient; and    a valve connected to said proximal end of said cannula, said valve having a seal which defines a restricted flow path in its undisturbed state and which is capable of expanding to define an enlarged flow path to permit fluid communication through said proximal end of said cannula, said seal being further capable of retracting to define said restricted flow path, said seal simultaneously urging any fluid within said enlarged flow path into said cannula.    
     
     
         37 . A method of introducing a fluid into the vasculature of a patient, the method comprising: 
 inserting a distal end of a cannula into the vasculature of the patient, said cannula having a valve connected to its proximal end, said valve comprising a housing and a seal;    placing a medical device into fluid communication with said seal;    operating said medical device so as to transfer said fluid through said cannula and the vasculature of the patient; and    withdrawing said medical device from said seal;    wherein said seal is made of a flexible material, and has a distal end in fluid communication with said cannula, a proximal end suitable for receiving said medical device, and a normally substantially closed passage in fluid communication with the distal end and the proximal end, the passage having a relatively small interior volume when in an undisturbed state and a larger interior volume upon the introduction of the medical device into the proximal end of the passage, the passage retracting to define a restricted flow path and a relatively small interior volume upon the withdrawal of the medical device from the seal, the proximal end initially being sealed as the second medical device is withdrawn, so that any of said fluid occupying the interior volume is forced toward the distal end as the passage walls collapse.    
     
     
         38 . The method defined in  claim 37 , wherein said passage has a region of minimum width that maintains substantially fluid-tight contact against substantially the entire perimeter of the medical device at an area near the proximal end of the seal.  
     
     
         39 . The method defined in  claim 37 , wherein the seal comprises: 
 a body made of flexible material and having a distal end and a proximal end opposite the distal end, the distal and proximal ends of the body being oriented to correspond to the distal and proximal ends of the seal;    a lead lumen formed in the distal end of the body and in fluid communication with the passage;    a neck formed at the second end of the body; and    a transverse flange at an end of the neck opposite the body, the transverse flange having at least one passage opening in fluid communication with the passage.    
     
     
         40 . The method defined in  claim 37 , wherein the step of inserting said distal end of said cannula into the vasculature of the patient comprises: 
 inserting an introducer sheath into the vasculature;    inserting a distal portion of a guidewire through said introducer sheath and into the vasculature;    placing said cannula over said guidewire;    advancing said cannula along said guidewire until said distal end enters the vasculature;    withdrawing said guidewire from said cannula; and    removing said introducer sheath.    
     
     
         41 . The method defined in  claim 40 , wherein the step of removing said introducer sheath is performed after the step of advancing said cannula along said guidewire until said distal end enters the vasculature.  
     
     
         42 . The method defined in  claim 40 , wherein the step of removing said introducer sheath is performed before the step of advancing said cannula along said guidewire until said distal end enters the vasculature.  
     
     
         43 . The method defined in  claim 37 , wherein a guidewire is disposed within said cannula and said seal.  
     
     
         44 . The method defined in  claim 43 , wherein the step of inserting said distal end of said cannula into the vasculature of the patient comprises: 
 inserting an introducer sheath into the vasculature; and    inserting a distal portion of said cannula through said introducer sheath and into the vasculature.    
     
     
         45 . A method of facilitating replacement of a first connector which is in fluid communication with a cannula implanted into a patient's vasculature, with a second connector, said method comprising: 
 interposing a valve between said first connector and a proximal end of said cannula, said valve comprising: 
 a housing; and  
 a seal disposed within said housing, wherein said seal defines a restricted flow path in its undisturbed state and is capable of expanding to define an enlarged flow path to permit fluid communication past said proximal end of said cannula, said seal being further capable of retracting to define said restricted flow path, said seal simultaneously urging any fluid within said enlarged flow path into said cannula;  
   removing said first connector from a proximal end of said valve so as to permit said seal to retract to define said restricted flow path; and    connecting said second connector to said valve, thereby causing said valve to expand to define said enlarged flow path.