Guidelines for the use of digital tourniquets based on physiological pressure measurements

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.