A occlusion detector for a dual-port surgical
tourniquet system comprises: a
tourniquet cuff for encircling a patient's 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 an indication of the pressure in the cuff over a time period suitably long for the performance of a surgical procedure, pressure regulation means communicating with the second pneumatic passageway for regulating the pressure in the cuff near a reference
pressure level, and an
occlusion detector for introducing a
pneumatic pressure pulse into the first pneumatic passageway during an
occlusion detection time period, for monitoring the pressure in the second pneumatic passageway during the
occlusion detection time period, and for producing an occlusion alarm if a fluctuation of pressure in the second pneumatic passageway is not detected within the
occlusion detection time period.