Reduction of recirculation in catheters

Abstract

A catheter tip designed to reduce the outflow velocity and/or directional momentum of fluid being infused by a catheter having such a tip. In one variation, a plurality of channels is provided at the distal portion of the catheter to increase the outflow cross-sectional area. In another variation, the diameter of the catheter at its distal portion where the fluid exits is increased. In yet another variation, a bullet-shaped nose is implemented which may decrease turbulence at the distal end of catheter tip. The low velocity outflow catheter tip may also be implemented on a dual lumen catheter, such as a hemodialysis catheter, to reduce recirculation rate. Various device configurations and methods for such implementations are also disclosed.

1 . A catheter for insertion into a mammalian body, comprising: 
 an elongated tubular body comprising a primary channel that extends from a proximal end of said tubular body to a distal end thereof, and a plurality of secondary channels in fluid communication with said primary channel, wherein each of said secondary channels terminate in an opening in said distal end of said tubular body such that the number of openings in said distal end of said tubular body is equal to the number of said secondary channels.    
   
   
       2 . The catheter according to  claim 1 , wherein said distal end of said tubular body is configured with a bullet shaped profile.  
   
   
       3 . The catheter according to  claim 2 , wherein a combined cross-sectional area of said secondary channels is larger than a cross-sectional area of said primary channel.  
   
   
       4 . The catheter according to  claim 3 , wherein the combined cross-sectional area of said secondary channels is at least 50% larger than the cross-sectional area of said primary channel.  
   
   
       5 . The catheter according to  claim 3 , wherein the combined cross-sectional area of said secondary channels is at least twice the cross-sectional area of said primary channel.  
   
   
       6 . The catheter according to  claim 1 , wherein said openings are arranged in a radial manner on said distal end of said tubular body.  
   
   
       7 . The catheter according to  claim 2 , wherein said openings are arranged in a radial manner on said bullet shaped profile.  
   
   
       8 . The catheter according to  claim 1 , wherein said plurality of secondary channels are arranged in a radial configuration and commonly diverge from a distal end of said primary channel.  
   
   
       9 . The catheter according to  claim 1 , wherein said tubular body further encloses a tertiary channel extending from said proximal end to said distal end, wherein said tertiary channel terminates in at least one opening positioned proximal said secondary channels.  
   
   
       10 . The catheter according to  claim 9 , wherein said tertiary channel is positioned in a coaxial manner around said primary channel.  
   
   
       11 . The catheter according to  claim 9 , wherein said at least one opening comprises a plurality of orifices.  
   
   
       12 . The catheter according to  claim 11 , wherein said orifices are arranged in a radial manner around the circumference of said tubular body.  
   
   
       13 . The catheter according to  claim 11 , wherein each of said plurality of orifices is configured with a tapered profile.  
   
   
       14 . The catheter according to  claim 1 , wherein said openings are configured such that fluid exits therefrom at a flow velocity that is less than the flow velocity along said primary channel.  
   
   
       15 . The hemodialysis catheter according to  claim 1 , wherein said openings are configured such that fluid exits therefrom at an angle away from a central axis of said catheter.  
   
   
       16 . A method of performing a hemodialysis procedure, comprising the steps of: 
 infusing fluid into a patient's body through a catheter;    reducing the velocity of fluid flow as the fluid enters a distal section of said catheter; and    directing at least part of a fluid outflow momentum of said fluid in a plurality of directions away from an area directly distal said distal section of said catheter as said fluid exits said catheter.    
   
   
       17 . The method according to  claim 16 , wherein said fluid exiting said distal section of said catheter is at least partially directed into said patient's right atrium.  
   
   
       18 . The method according to  claim 17 , further comprising the step of withdrawing blood from said patient's superior vena cava while said fluid is being injected into said patient's right atrium.  
   
   
       19 . A method of infusing blood, comprising the steps of: 
 providing a catheter, having at least one lumen;    positioning a distal end of the catheter in close proximity to the tricuspid valve of a patient's heart; and    synchronizing infusion of blood through said lumen to coincide with the filling and emptying of the patient's right atrium, such that blood is released into the atrium when the tricuspid valve opens.    
   
   
       20 . The method according to  claim 19 , wherein the step of synchronizing infusion further comprises monitoring the patient's electrocardiogram and infuse blood into the right atrium through said catheter when the right atrium is being emptied, and decrease or stop infusion of blood through said catheter when the right atrium is being filled.  
   
   
       21 . The method according to  claim 19 , wherein the step of synchronizing infusion further comprises monitoring the patient's electrocardiogram and infused blood into the right atrium through said catheter during a P-wave period, and decrease or stop infusion of blood through said catheter at the end of said P-wave period.  
   
   
       22 . The method according to  claim 19 , wherein the step of synchronizing infusion further comprises monitoring the patient's electrocardiogram and modulate a blood pump which drives the blood into the catheter such that pumping of the blood is synchronized with heart beat cycles within the electrocardiogram.  
   
   
       23 . The method according to  claim 22  further comprising the step of increasing the pump rate during a P-wave period, and decreasing the pump rate when the electrocardiogram is outside of the P-wave period.  
   
   
       24 . The method according to  claim 19 , wherein the step of synchronizing infusion further comprises monitoring the patient's electrocardiogram and synchronize the infusion of the blood through the catheter with heart beat cycles in the electrocardiogram.  
   
   
       25 . The method according to  claim 19 , further comprising the step of: 
 withdrawing blood from the patient's superior vena cava through a second lumen of said catheter.    
   
   
       26 . The method according to  claim 25 , wherein the withdrawing step further comprises synchronizing the withdrawal of blood with the infusion of blood.  
   
   
       27 . The method according to  claim 25 , wherein blood is being continuously withdrawn from the superior vena cava through said second lumen.