Patent ID: 7479154

Claim:
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 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.