METHOD AND APPARATUS FOR IMPROVING VENOUS ACCESS
Embodiments of the invention include a method and a device for increasing vasodilatation and/or controlling the temperature of a mammal by applying a desired vacuum pressure to the skin of the extremity of a mammal. In some cases it is also desirable to provide heat to regions of the extremity of the mammal to further dilate the veins or arteries in the patient. In some cases it is also desirable to apply a contact pressure to regions of the extremity of the mammal to improve perfusion of these regions. In one embodiment, the device includes a device that is adapted to rigidly enclose a portion of an extremity of the mammal therein so that a sub-atmospheric pressure can be applied to the mammal's extremity, which is further discussed below.
1 . A method of venous access in a extremity of a mammal, comprising:
positioning a portion of an extremity of a mammal in an internal region that is at least partially enclosed by one or more flexible walls;
evacuating the internal region to a pressure below atmospheric pressure to expose the portion of the extremity of the mammal to the pressure below atmospheric pressure;
adjusting the pressure in the internal region;
transferring heat from a thermal exchange unit to the portion of the extremity; and
injecting a fluid or removing blood from a vein or artery in the extremity that has been dilated or distended by the transfer of heat to the portion of the extremity and the exposure of the portion of the extremity to the pressure below atmospheric pressure.
2 . The method of claim 1 , further comprising:
positioning the thermal exchanging unit on a surface of the extremity that is positioned within the internal region so that the one or more flexible walls will collapse against the thermal exchange unit when the pressure is adjusted in the internal region; and
the transferring heat further comprises controlling the temperature of the one or more thermal exchange units.
3 . The method of claim 1 , further comprising sealing a portion of the one or more flexible walls to the extremity to enclose the internal region.
4 . The device of claim 1 , wherein adjusting the pressure in the internal region comprises evacuating the internal region to a pressure between about −5 mmHg and about −80 mmHg.
5 . The method of claim 2 , wherein controlling the temperature of the one or more thermal exchange units comprises providing a surface of the one or more thermal exchange units that is in contact with the extremity to be at a temperature between about 0° C. and about 43° C.
6 . The method of claim 1 , further comprising applying a compression force to the extremity of the mammal.
7 . The method of claim 1 , further comprising:
connecting the thermal exchange unit to a fluid controller;
connecting the internal region to a pump; and
controlling the temperature of the thermal exchange unit and the pressure in the internal region.
8 . The method of claim 1 , further comprising:
positioning a compression member having one or more flexible walls that enclose a compression member internal region over a portion of the extremity; and
applying a compression force to the extremity of the mammal by delivering a pressure greater than atmospheric pressure to the compression member internal region to cause the one or more flexible walls of the compression member to contact the portion of the extremity.
9 . A method of venous access in a extremity of a mammal, comprising:
positioning a portion of an extremity of a mammal over a heat exchange surface that has a convex shape, wherein the heat exchange surface and the portion of the extremity are disposed in an internal region that is enclosed by a body element;
urging a portion of the extremity against the convex heat exchanging surface;
evacuating the internal region to a pressure below atmospheric pressure to expose the portion of the extremity of the mammal to the pressure below atmospheric pressure;
transferring heat from the one or more thermal exchange units to the portion of the extremity while the portion of the extremity is urged against the convex heat exchanging surface; and
injecting a fluid or removing blood from a vein or artery in the extremity that has been dilated or distended by the transfer of heat to the portion of the extremity and the exposure of the portion of the extremity to the pressure below atmospheric pressure.
10 . The method of claim 9 , wherein the body element comprises one or more flexible walls that at least enclose a portion of the internal region, wherein the one or more flexible walls are adapted to collapse onto a portion of the extremity when the internal region is evacuated to a pressure below atmospheric pressure.
11 . The device of claim 9 , wherein adjusting the pressure in the internal region comprises evacuating the internal region to a pressure between about −5 mmHg and about −80 mmHg.
12 . The method of claim 10 , wherein controlling the temperature of the one or more thermal exchange units comprises providing a surface of the one or more thermal exchange units that is in contact with the extremity to be at a temperature between about 0° C. and about 43° C.
13 . The method of claim 9 , further comprising applying a compression force to the extremity of the mammal.
14 . A device for improving venous access, comprising:
a body element having one or more walls that enclose an internal region;
an opening formed in the body element that is adapted to receive an extremity of a mammal and allow a portion of the extremity to be positioned within the internal region;
a heat exchange surface that has a convex shape and is disposed in the internal region;
one or more thermal exchanging units that are in thermal contact with the heat exchange surface;
a fluid source that is in fluid communication with the one or more thermal exchanging units; and
a pump that is adapted to control the pressure within the internal region to a sub-atmospheric pressure.
15 . The device of claim 14 , further comprising a controller unit connected to one or more pressure ports and the one or more thermal exchange units, wherein the controller unit is adapted to simultaneously control the pressure in the internal region through the one or more pressure ports that are attached to the body element and control the temperature of the heat exchanging surface by controlling the fluid flow and temperature of a liquid through the one or more thermal exchanging units.
16 . The device of claim 14 , further comprising a sealing member that is adapted to form a seal between the body element and a portion of the extremity, wherein the sealing member comprises a material selected form the group consisting of hydrogel, urethane and combinations thereof.
17 . The device of claim 14 , wherein the one or more thermal exchange units are electric pads.
18 . The device of claim 14 , wherein the extremity is selected from the group consisting of a hand, a forearm, a forearm with an elbow, a hand with a wrist, a foot, a leg, a calf, and an ankle.
19 . The device of claim 14 , wherein the material of the body elements is a material selected form the group consisting of urethane, polyurethane, polypropylenes, polystyrenes, high density polyethylene, low density polyethylene, and poly(vinyl chloride).
20 . The device of claim 14 , wherein the material of the body elements is a material selected form the group consisting of stainless steel, titanium, glass, aluminum, an acrylic material, polystyrene, high density polyethylene (HDPE), low density polyethylene (LDPE), poly(vinyl chloride), polypropylene, or any other biocompatible material.