Multi-lumen cannula

DETAILED DESCRIPTION The cannula according to the invention overcomes the problems of the prior art by providing a multi-lumen cannula with independently reinforced lumens so that dramatically different fluid pressures can be accommodated in the same multi-lumen cannula.
In addition, the cannula according to the invention achieves some of the desirable goals of cardiac surgery by minimizing the number of incisions which must be created in the heart and the vessels leading to and from the heart.
In a first aspect, the multi-lumen cannula according to the invention comprises at least two lumens formed in the cannula.
The lumens have proximal and distal ends and fluid inlet and outlet apertures.
A septum is provided which separates the first and second lumens from one another.
The septum is reinforced to resist deflection of the septum in response to fluid pressure differentials in the adjacent lumen.
With this structure, dramatically different fluid pressures can be accommodated in the two adjacent lumens without deflection of the septum into the lower pressure lumen.
In the preferred embodiment, the lumens are wire reinforced.
In another aspect of the invention, the multi-lumen cannula is an assembly of a first sub-cannula and a second sub-cannula.
Each of the sub-cannulas has a proximal end, a distal end, and a lumen extending between the ends.
Once again, apertures are formed in the lumens to accommodate the flow of fluid therethrough.
A portion of the first sub-cannula is adhered to a portion of the second sub-cannula to create a septum separating the lumens of the two sub-cannulas.
Once again, the preferred embodiment of the septum includes wire reinforcement to resist deflection of the septum and thereby accommodate varying fluid pressure levels inside the lumens.
In still another aspect of the invention, the multi-lumen cannula comprises an assembly of two sub-cannulas substantially similar to those described above.
However, in this embodiment, the adhered portion of the first and second sub-cannulas are non-circular in cross section wherein the non-adhered portions of the sub-cannulas are substantially circular in cross section