Surgical tourniquet apparatus for measuring limb occlusion pressure
First Claim
1. Tourniquet apparatus for rapidly and accurately measuring a patient'"'"'s limb occlusion pressure comprising:
- an inflatable tourniquet cuff for encircling a limb at a location;
a tourniquet instrument releasably connectable to the cuff and includingpressure sensing means for producing a cuff pressure signal indicative of the level of pressure in the cuff,pressure regulation means communicating with the cuff and responsive to the cuff pressure signal for regulating the pressure in the cuff near a reference pressure level,blood flow transducing means adapted for applying to a portion of the limb distal to the cuff to transmit light through the portion of the limb, thereby to produce a blood flow signal indicative of blood flow in the portion,compensation means for compensating for reduction of the light transmission attributable to increases in the volume of venous blood in the portion of the limb; and
limb occlusion pressure means responsive to the blood flow signal and the cuff pressure signal and operable for detecting arterial pulsations of blood flow, for increasing the reference pressure level in synchrony with the arterial pulsations and for producing a limb occlusion pressure value indicative of the lowest level of pressure in the cuff at which the magnitude of the arterial pulsations is less than a minimum detection threshold.
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Accused Products
Abstract
Tourniquet apparatus for rapidly and accurately measuring a patient'"'"'s limb occlusion pressure comprises: an inflatable tourniquet cuff for encircling a limb at a location; a tourniquet instrument releasably connectable to the cuff that includes: pressure sensing means for producing a cuff pressure signal indicative of the level of pressure in the cuff; pressure regulation means communicating with the cuff and responsive to the cuff pressure signal for regulating the pressure in the cuff near a reference pressure level; blood flow transducing means adapted for applying to a portion of the limb distal to the cuff to produce a blood flow signal indicative of blood flow in the portion; and limb occlusion pressure means responsive to the blood flow signal and the cuff pressure signal and operable for detecting arterial pulsations of blood flow, for increasing the reference pressure level in synchrony with the arterial pulsations and for producing a limb occlusion pressure value indicative of the lowest cuff pressure at which the magnitude of the arterial pulsations is less than a minimum detection threshold.
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Citations
14 Claims
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1. Tourniquet apparatus for rapidly and accurately measuring a patient'"'"'s limb occlusion pressure comprising:
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an inflatable tourniquet cuff for encircling a limb at a location; a tourniquet instrument releasably connectable to the cuff and including pressure sensing means for producing a cuff pressure signal indicative of the level of pressure in the cuff, pressure regulation means communicating with the cuff and responsive to the cuff pressure signal for regulating the pressure in the cuff near a reference pressure level, blood flow transducing means adapted for applying to a portion of the limb distal to the cuff to transmit light through the portion of the limb, thereby to produce a blood flow signal indicative of blood flow in the portion, compensation means for compensating for reduction of the light transmission attributable to increases in the volume of venous blood in the portion of the limb; and limb occlusion pressure means responsive to the blood flow signal and the cuff pressure signal and operable for detecting arterial pulsations of blood flow, for increasing the reference pressure level in synchrony with the arterial pulsations and for producing a limb occlusion pressure value indicative of the lowest level of pressure in the cuff at which the magnitude of the arterial pulsations is less than a minimum detection threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Tourniquet apparatus for rapidly and accurately measuring a patient'"'"'s limb occlusion pressure comprising:
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a tourniquet cuff for encircling a patient'"'"'s limb at a location on the limb and including an inflatable portion that communicates pneumatically with a first cuff port and that communicates pneumatically with a second cuff port independently of the first cuff port; a tourniquet instrument that is releasably connectable to the first and second cuff ports to establish first and second pneumatic passageways between the tourniquet cuff and the tourniquet instrument, wherein the tourniquet instrument includes pressure sensing means communicating with the first pneumatic passageway for producing a cuff pressure signal indicative of the level of pressure in the cuff, pressure regulation means communicating with the second pneumatic passageway and responsive to the cuff pressure signal for regulating the pressure in the cuff near a reference pressure level, blood flow signal processing means adapted for producing blood flow signals indicative of blood flow past the cuff and for processing the signals into non-pulsatile components as well as an arterial pulsations, and limb occlusion pressure means for detecting the non-pulsatile components and the arterial pulsations for increasing the reference pressure level in synchrony with the arterial pulsations, and for producing a limb occlusion pressure value indicative of the lowest cuff pressure at which the magnitude of the arterial pulsations is less than a minimum detection threshold and for compensating for increases in the volume of venous blood in the patient'"'"'s limb distal to the cuff that would, in the absence of compensation, reduce at least the level of the non-pulsatile component of the blood flow signal. - View Dependent Claims (9, 10, 11)
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12. A method of rapidly and accurately measuring a patient'"'"'s limb occlusion pressure comprising the steps of:
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applying an inflatable tourniquet cuff to a patient'"'"'s limb; connecting the tourniquet cuff to a tourniquet instrument for inflating and the applied tourniquet cuff to a pressure near a reference pressure level; measuring the pressure of gas within the inflated tourniquet cuff; detecting, using light transmission, pulsations of arterial blood flow past the tourniquet cuff into the limb distal to the cuff; compensating for reduction of the light transmission attributable to increases in the volume of venous blood in the patient'"'"'s limb distal to the cuff; increasing the reference pressure level in synchrony with the arterial pulsations; and determining the lowest pressure of gas within the inflated tourniquet cuff at which the magnitude of the arterial pulsations is less than a minimum detection threshold. - View Dependent Claims (13, 14)
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Specification