Method to augment blood circulation in a limb

A method for measuring venous refill time in a limb to which intermittent pneumatic compression is applied, comprising:

• (a) providing an intermittent pneumatic compression system for applying pressure to the limb, the system having a compression sleeve having a plurality of pressurizable chambers, a source of compressed gas in communication with the pressurizable chambers via tubing, and a controller in communication with the source of compressed gas and the tubing to control application of compressed gas to the pressurizable chambers and operative to direct compressed gas to the pressurizable chambers and depressurize the pressurizable chambers;
• (b) wrapping the limb with the compression sleeve;
• (c) pressurizing the pressurizable chambers with a gas for a predetermined period of time sufficient to compress the limb to cause blood in the limb to flow out of the limb;
• (d) depressurizing the pressurizable chambers until pressure in one or more of the pressurizable chambers reaches a lower value;
• (e) closing at least the one of the pressurizable chambers;
• (f) sensing pressure in at least the one of the pressurizable chambers, the change in pressure being an indication of blood volume change in the limb;
• (g) determining a venous refill time comprising the time difference from the beginning of the step of depressurizing the pressurizable chambers until a time when the pressure reaches a plateau;
• and
• (h) depressurizing subsequent compression cycles for a period of time based on the venous refill time.

A method for augmenting blood flow by applying pressure to a limb, comprising:

• wrapping the limb with a sleeve having at least one pressurizable chamber;
• pressurizing the pressurizable chamber with a gas for a period of time sufficient to compress the limb to cause blood in the limb to flow out of the limb;
• depressurizing the pressurizable chamber until the pressure in the chamber reaches a lower value;
• closing the pressurizable chamber;
• sensing pressure in the chamber, the pressure being an indication of blood volume change in the limb;
• determining a time when the pressure reaches a plateau;
• determining a venous refill time comprising the time difference between beginning the step of depressurizing the pressurizable chamber and the time when the pressure reaches the plateau;
• and
• depressurizing subsequent compression cycles for a period of time based on the venous refill time.

A method for augmenting blood flow by applying pressure to two limbs of a patient, comprising:

• wrapping a first limb with a first sleeve having a first pressurizable chamber and wrapping a second limb with a second sleeve having a second pressurizable chamber;
• pressurizing the first and second pressurizable chambers with a gas for a predetermined period of time sufficient to compress the first and second limbs to cause blood in the first and second limbs to flow out of the first and second limbs;
• depressurizing the first and second pressurizable chambers until the pressure in both of the first and second pressurizable chambers reaches a lower value;
• closing the first and second pressurizable chambers;
• sensing the pressure in the first and second pressurizable chambers, a change in pressure being an indication of blood volume change in the first and second limbs;
• determining a time from beginning the depressurizing of the first and second pressurizable chambers until the pressure reaches a plateau in both of the first and second pressurizable chambers, the time comprising a venous refill time;
• and
• depressurizing subsequent compression cycles in the first and second sleeves for a period of time based on the venous refill time.