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.