Medical valve with positive flow characteristics

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.

A method of preventing blood from flowing out of a patient into a catheter when a syringe is withdrawn from a valve between the syringe and the catheter, the method comprising the steps of: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.

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.

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.

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.

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.

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.