Methods for adaptive limb occlusion

Inventors

Leschinsky, Boris

Assignees

Infarct Reduction Technologies • INFARCT REDUCTION TECHNOLOGIES Inc

Abstract

Methods for adaptive cuff inflation for the purposes of occluding a limb of a subject include inflating a cuff to a pressure at or above limb occlusion pressure and periodically deflating the cuff to detect amplitude of oscillometric oscillations reaching or exceeding a predetermined threshold, whereby indicating that the cuff pressure has reached an updated systolic blood pressure. Selecting the cuff to be wide enough to define limb occlusion pressure at or below the systolic blood pressure assures that this maneuver does not compromise cessation of blood flow to the limb. Devices are disclosed configured to operate in at least two of the following three operating modes: a tourniquet mode, a remote conditioning mode and a blood pressure monitoring mode.

Core Innovation

The invention provides a method for adaptive limb occlusion of a subject using a cuff sized to be placed about a limb. The cuff is configured to define a limb occlusion pressure to be equal to or below a systolic blood pressure of the subject, and the method determines the systolic blood pressure by inflating the cuff placed about the same limb of the subject.

The method inflates the cuff to a pressure sufficient to cause cessation of blood flow through the limb for a period of cuff inflation lasting at least about one minute. During the period of cuff inflation, the method decreasing entire cuff pressure at least once, and detects oscillometric oscillations indicating the cuff pressure is above, equal to, and capable of being below an updated systolic blood pressure while at least equal to or being above the corresponding limb occlusion pressure.

After determining the updated systolic blood pressure, the method inflates the cuff to a pressure below, at or above the updated systolic blood pressure so that the pressure is sufficient to continue causing cessation of blood flow. In a related implementation, the method continuously or intermittently monitors cuff pressure to indicate that the entire cuff pressure is at or below systolic blood pressure while at or above the limb occlusion pressure, and upon the indication, inflates the cuff to a pressure exceeding the limb occlusion pressure by a predetermined safety margin.

Claims Coverage

The partial content provides two independent claims, one method claim with an oscillometric update during cuff inflation and a second method claim with continuous or intermittent monitoring and a safety-margin increase. Across these independent claims, the key inventive features total four main concepts: cuff sizing or configuration tied to limb occlusion pressure relative to systolic blood pressure, an initial inflation to cause cessation of blood flow for at least about one minute, monitoring using oscillometric oscillations to determine an updated systolic blood pressure and preserve blood-flow cessation during pressure reduction, and re-inflation based on the updated systolic blood pressure or a predetermined safety margin to maintain cessation of blood flow.

The independent claims cover an adaptive limb occlusion method in which a cuff is configured so limb occlusion pressure is at or below systolic blood pressure, an initial inflation stops blood flow for at least about one minute, and oscillometric oscillations are used to determine or confirm an updated systolic blood pressure while maintaining blood-flow cessation. The method then re-inflates to continue cessation, either based on the updated systolic blood pressure or by increasing above the limb occlusion pressure by a predetermined safety margin.

Stated Advantages

Documented Applications