A potential complication of a digital tourniquet is neurovascular damage
due to excessive tissue pressure. A technique for measuring digital
tourniquet pressures was developed in our laboratory and was tested on
fresh cadaver hands in order to establish guidelines for proper application
of tourniquets. A saphenous vein from a fresh cadaver was laid
subcutaneously along the neurovascular bundle of the test finger. Digital
tourniquets consisting of Penrose drains or rolled surgical gloves were
then applied in a standardized fashion. Saline solution was injected
through the saphenous vein in a quasi-static fashion using a Harvard pump,
and the pressure within the vein was monitored with a pressure transducer.
When the pressure within the vein reached the closing pressure generated by
the tourniquet, the pressure stabilized due to leakage of fluid beyond the
tourniquet. Digital tourniquets applied in customary fashion by selected
physicians and surgeons produced a wide range of closing pressures that did
not exceed 360 millimeters of mercury. Rolled surgical gloves produced
closing pressures ranging from 113 to 363 millimeters of mercury, depending
on the relationship between the size of the glove and that of the hand.
Penrose drains produced closing pressures of more than 800 millimeters of
mercury, depending on the amount of stretch applied.