Gradient sequential compression system and method for reducing the occurrence of deep vein thrombosis

A method of providing a prophylactic modality to a limb of a user, comprising the steps of:

• compressing a first distal portion of the limb to thereby provide a first radially inwardly directed compressive force about the limb at the first distal portion;
• then
• compressing a second portion of the limb, adjacent the first distal portion, to thereby provide a second radially inwardly directed compressive force about the limb at the second portion;
• and
• regulating the first compressive force at a level greater than the second compressive force, so that a monotonically decreasing compression gradient is established in a proximal direction between the first distal portion and the second portion for a predetermined time interval, by
• measuring the first compressive force and the second compressive force during the predetermined time interval, and
• independently increasing the radially inwardly directed compressive forces one-at-a-time at the first distal portion and at the second portion if the first and second compressive forces decrease to levels less than respective first and second predetermined compressive forces.

In a gradient sequential compression system for facilitating the prevention of deep vein thrombosis and pulmonary embolism in a limb of a recumbent user, a method of providing a prophylactic modality to the limb using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• inflating a first chamber of the limb sleeve;
• sampling a pressure in the first chamber to obtain a first sample;
• then
• inflating the first chamber of the limb sleeve from a first pressure, which is greater than or equal to the first sample, to a second higher pressure, which is greater than or equal to a first predetermined chamber pressure, prior to commencement of a first time interval;
• inflating a second chamber of the limb sleeve, disposed proximally relative to the first chamber, to a second predetermined chamber pressure, after a pressure in the first chamber has been established at the first predetermined chamber pressure for the first time interval;
• independently adjusting the pressures in the first and second chambers so that a monotonically decreasing pressure gradient is established in a proximal direction between the first chamber and the second chamber;
• and
• deflating the first and second chambers from the first and second predetermined chamber pressures, respectively, to pressures less than the second predetermined chamber pressure.

A method of applying compressive forces to a limb of a person using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• pressurizing a first chamber of the limb sleeve;
• then
• sampling a pressure in the first chamber to obtain a first pressure sample;
• then
• adjusting the pressure in the first chamber to a first predetermined chamber pressure, based on the first sample, prior to commencement of a first time interval;
• then
• pressurizing a second chamber of the limb sleeve, disposed proximally relative to the first chamber, to a second predetermined chamber pressure, after the pressure in the first chamber has been maintained at the first predetermined chamber pressure for the first time interval;
• then
• sampling a pressure in the second chamber to obtain a second pressure sample, while simultaneously preventing depressurization or pressurization of the first chamber;
• then
• adjusting the pressure in the second chamber to a second predetermined chamber pressure, based on the second sample, while simultaneously preventing depressurization or pressurization of the first chamber;
• and
• depressurizing the first and second chambers from the first and second predetermined chamber pressures, respectively, to pressures less than the second predetermined chamber pressure.

A method of applying compressive forces to a limb of a person using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• independently pressurizing the chambers of the limb sleeve one-at-a-time by pressurizing a first chamber of the limb sleeve to a first predetermined chamber pressure;
• then pressurizing a second chamber of the limb sleeve, disposed proximally relative to the first chamber, to a second predetermined chamber pressure, after the first chamber reaches the first predetermined chamber pressure;
• then
• independently regulating the pressures in the first and second chambers one-at-a-time at the first and second predetermined chamber pressures, respectively, so that a pressure gradient is established in a proximal direction between the first chamber and the second chamber;
• and
• depressurizing the first and second chambers from the first and second predetermined chamber pressures, respectively, to pressures less than the second predetermined chamber pressure.

A method of using a multi-chambered inflatable sleeve to provide a prophylactic modality to a limb of a recumbent user through repeated squeezing and relaxing action, comprising the steps of:

• inflating a first chamber of the sleeve to a first predetermined chamber pressure during a first inflation cycle;
• then
• inflating a second chamber of the sleeve to a second predetermined chamber pressure after a pressure in the first chamber reaches the first predetermined chamber pressure during the first inflation cycle;
• then
• periodically adjusting the pressures in the first and second chambers during the first inflation cycle, respectively, so that a monotonically decreasing pressure gradient is established in a proximal direction between the first chamber and the second chamber, by
• sampling a pressure in the first chamber to obtain a first sample and then adjusting the pressure in the first chamber, based on the first sample;
• sampling a pressure in the second chamber to obtain a second sample and then adjusting the pressure in the second chamber, based on the second sample;
• repeatedly sampling the pressure in the first chamber to obtain a plurality of first samples;
• repeatedly sampling the pressure in the second chamber to obtain a plurality of second samples;
• and
• deflating the first and second chambers, said deflating step including the steps of averaging the first samples to obtain an average first chamber pressure;
• and disabling inflation of the first chamber during a subsequent inflation cycle if the average first chamber pressure exceeds a predetermined critical pressure.

A method of applying compressive forces to a limb of a person using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• pressurizing a first chamber of the limb sleeve;
• then
• sampling a pressure in the first chamber to obtain a first pressure sample;
• then
• adjusting the pressure in the first chamber to a first predetermined chamber pressure, based on the first sample;
• then
• pressurizing a second chamber of the limb sleeve, disposed proximally relative to the first chamber, after the pressure in the first chamber has been maintained at the first predetermined chamber pressure for a first time interval;
• then
• sampling a pressure in the second chamber to obtain a second pressure sample, while simultaneously preventing depressurization or pressurization of the first chamber;
• then
• adjusting the pressure in the second chamber to a second predetermined chamber pressure, based on the second sample, while simultaneously preventing depressurization or pressurization of the first chamber;
• then
• sampling a pressure in the first chamber, after a pressure in the second chamber reaches the second predetermined chamber pressure, to obtain a third pressure sample, while simultaneously preventing depressurization of the second chamber;
• then
• adjusting the pressure in the first chamber to the first predetermined chamber pressure, based on the third sample;
• and
• depressurizing the first and second chambers, said depressurizing step including the steps of averaging the first and third pressure samples to obtain an average first chamber pressure and then disabling inflation of the first chamber during a subsequent inflation cycle if the average first chamber pressure exceeds a predetermined critical pressure.

A method of applying compressive forces to a limb of a person using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• inflating a first chamber of the limb sleeve from a deflated condition during a first inflation cycle;
• then
• sampling a pressure in the first chamber to obtain a first sample;
• then
• inflating the first chamber from a pressure equal to the first sample to at least a first predetermined chamber pressure, if the first sample is less than the first predetermined chamber pressure;
• initiating a timer to determine a duration of a first time interval if the first sample is greater than or equal to the first predetermined chamber pressure;
• then
• inflating a second chamber of the limb sleeve, disposed proximally relative to the first chamber, from a deflated condition at the end of the first time interval;
• then
• sampling a pressure in the second chamber to obtain a second sample;
• then
• inflating the second chamber from a pressure equal to the second sample to a second predetermined chamber pressure, if the second sample is less than the second predetermined chamber pressure;
• then
• deflating the first and second chambers from the first and second predetermined chamber pressures to their respective deflated conditions;
• then
• inflating the first chamber of the limb sleeve during a second inflation cycle, subsequent to the first inflation cycle;
• then
• inflating a second chamber of the limb sleeve, disposed proximally relative to the first chamber, during the second inflation cycle;
• wherein a duration of the step of inflating the first chamber of the limb sleeve during the second inflation cycle is greater than or less than a duration of the step of inflating the first chamber of the limb sleeve during the first inflation cycle if the first sample is less than or greater than the first predetermined chamber pressure, respectively;
• and
• wherein a duration of the step of inflating the second chamber of the limb sleeve during the second inflation cycle is greater than or less than a duration of the step of inflating the second chamber of the limb sleeve during the first inflation cycle if the second sample is less than or greater than the second predetermined chamber pressure, respectively.

A method of applying compressive forces to a limb of a person using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• inflating a first chamber of the limb sleeve from a deflated condition for a first chamber inflation time;
• sampling a pressure in the first chamber to obtain a first pressure sample;
• adjusting the first chamber inflation time upward or downward if at the end of said first chamber inflating step the first pressure sample is below or above a first predetermined chamber pressure, respectively, and storing the adjusted first inflation time in a memory;
• inflating a second chamber of the limb sleeve, disposed proximally relative to the first chamber, from a deflated condition for a second chamber inflation time;
• sampling a pressure in the second chamber to obtain a second pressure sample;
• adjusting the second chamber inflation time upward or downward if at the end of said second chamber inflating step the second pressure sample is below or above a second predetermined chamber pressure, respectively, and storing the adjusted second inflation time in the memory;
• deflating the first and second chambers of the limb sleeve from the first and second predetermined chamber pressures, respectively;
• subsequent to said deflating step, inflating the first chamber of the limb sleeve for the adjusted first chamber inflation time;
• and
• subsequent to said deflating step, inflating the second chamber of the limb sleeve for the adjusted second chamber inflation time.

In a gradient sequential compression system for facilitating the prevention of deep vein thrombosis and pulmonary embolism in a limb of a recumbent user, a method of providing a prophylactic modality to the limb using a multi-chambered inflatable limb sleeve surrounding the limb, comprising the steps of:

• inflating a first chamber of the limb sleeve from a deflated condition;
• sampling a pressure in the first chamber to obtain a first sample;
• then
• inflating the first chamber of the limb sleeve from a first pressure, which is greater than or equal to the first sample, to a second higher pressure, which is greater than or equal to a first predetermined chamber pressure, prior to commencement of a first time interval;
• then
• inflating a second chamber of the limb sleeve, disposed proximally relative to the first chamber, from a deflated condition to a second predetermined chamber pressure, after a pressure in the first chamber has been established at the first predetermined chamber pressure for the first time interval;
• independently adjusting the pressures in the first and second chambers so that a monotonically decreasing pressure gradient is established in a proximal direction between the first chamber and the second chamber;
• and
• deflating the first and second chambers from the first and second predetermined chamber pressures, respectively, to pressures less than the second predetermined chamber pressure.