Paracardiac blood pump

Abstract

The paracardiac blood pump is destined designed for protruding through the cardiac wall into the heart with a portion of its housing ( 10 ) and for suctioning blood from the heart. The blood is pumped into one of the blood vessels connected with the heart through a line that extends outside the heart. A cannula ( 30 ) is arranged in front of the inlet ( 17 ) of the pump ring ( 16 ). The housing ( 10 ) and the cannula ( 30 ) have approximately the same outer diameters of 13 mm at most. The housing, together with the cannula ( 30 ), can thus be inserted into the heart through a puncture hole that is produced in the cardiac wall without removing material.

What is claimed is: 
     
       1. A paracardial blood pump, comprising:
 a tubular housing including a longitudinally extending flow channel and a drive unit for an impeller, said drive unit being arranged coaxially therein, and comprising, on the one end, a pump ring with an axial inlet surrounding the impeller and, on the other end, a laterally branching outlet tube; and 
 a cannula, arranged in front of said inlet of the pump ring, wherein the housing and the cannula have approximately the same outer diameters of a maximum of 13 mm. 
 
     
     
       2. The blood pump of  claim 1 , wherein the inner diameter of the outlet tube is about as large as that of the cannula. 
     
     
       3. The blood pump of  claim 1 , wherein the pump ring is cylindrical and that a transition region is provided behind the pump ring in the flow direction, the diameter of said transition region enlarging from that of the pump ring to that of the flow channel. 
     
     
       4. The blood pump of  claim 1 , further comprising a pressure sensor for detecting the pressure in the flow channel and wherein a signal from the pressure sensor is evaluated for the detection of different operating states and/or for the detection of the current volume flow. 
     
     
       5. The blood pump of  claim 4 , wherein the tubular housing has an outside wall and an axial end wall, characterized in that the pressure sensor or a pressure detection opening is arranged on the outside wall or the axial end wall or in the pump ring of the flow channel. 
     
     
       6. The blood pump of  claim 1 , wherein the cannula projects beyond the pump ring by less than the housing length. 
     
     
       7. The blood pump of  claim 1 , wherein the flow cross section in the region of the impeller is selected such that the reflux through the pump is less than 1 l/min at a counter pressure of 80 mm Hg when the pump is at a standstill. 
     
     
       8. The blood pump of  claim 1 , wherein the outlet tube has a cross section enlarging in the flow direction. 
     
     
       9. A paracardial blood pump, comprising:
 a tubular housing including a longitudinally extending flow channel and a drive unit for an impeller, said drive unit being arranged coaxially therein, and comprising, on the one end, a pump ring with an axial inlet surrounding the impeller and, on the other end, a laterally branching outlet tube; and   a cannula, arranged in front of the inlet of the pump ring, wherein the housing and the cannula have approximately the same outer diameter.   
     
     
       10. The blood pump of claim 9, wherein the inner diameter of the outlet tube is about as large as that of the cannula. 
     
     
       11. The blood pump of claim 9, wherein the pump ring is cylindrical and a transition region is provided behind the pump ring in the flow direction, the diameter of the transition region enlarging from that of the pump ring to that of the flow channel. 
     
     
       12. The blood pump of claim 9, further comprising a pressure sensor for detecting the pressure in the flow channel and wherein a signal from the pressure sensor is evaluated for the detection of different operating states and/or for the detection of the current volume flow. 
     
     
       13. The blood pump of claim 12, wherein the tubular housing has an outside wall and an axial end wall, wherein the pressure sensor or a pressure detection opening is arranged on the outside wall, or the axial end wall, or in the pump ring of the flow channel. 
     
     
       14. The blood pump of claim 9, wherein the cannula projects beyond the pump ring by less than the housing length. 
     
     
       15. The blood pump of claim 9, wherein the flow cross section in the region of the impeller is selected such that the reflux through the pump is less than 1 l/min at a counter pressure of 80 mm Hg when the pump is at a standstill. 
     
     
       16. The blood pump of claim 9, wherein the outlet tube has a cross section that increases in the flow direction. 
     
     
       17. The blood pump of claim 9, wherein the cannula comprises a plurality of longitudinally extending slots. 
     
     
       18. The blood pump of claim 9, wherein the pump is sized to be inserted into a human heart at its apex. 
     
     
       19. The blood pump of claim 9, further comprising a peripheral enlargement of the housing constructed and arranged to facilitate the fixing of the pump to the cardiac wall. 
     
     
       20. The blood pump of claim 9, wherein the impeller is positioned outside of the transition region. 
     
     
       21. The blood pump of claim 9, wherein the drive unit is fixed to the housing at only one end. 
     
     
       22. The blood pump of claim 9, wherein the drive unit operates at a speed of between 25,000 and 30,000 revolutions per minute. 
     
     
       23. The blood pump of claim 9, wherein the housing has an overall length of approximately 50 mm. 
     
     
       24. The blood pump of claim 23, wherein the portion of the cannula projecting beyond the housing has an overall length of approximately 35 mm.