The invention provides a nested tubing cannula which comprises outer and
inner elongate tubular members, both having a proximal end, a distal end,
and a lumen therebetween. The inner tubular member is sealed at its distal
end and is nested substantially coaxially within the lumen of the outer
tubular member, so that the gap between the inner and the outer tubular
member defines a second lumen whereas the first lumen is the lumen of the
inner tubular member. A tubular sleeve is disposed coaxially between the
inner and outer tubular members. A balloon is mounted on a distal region
of the outer tubular member and is in communication with the first lumen.
The cannula further comprises a port proximal or distal the balloon
occluder and is in communication with the second lumen. Methods for making
the devices herein are disclosed.