Tourniquet time
Formal Definition
The duration a pneumatic tourniquet remains inflated on an extremity during a surgical procedure to provide a bloodless operative field; the safe upper limit is generally 90-120 minutes for upper extremities and 120-180 minutes for lower extremities (with manufacturer recommendations varying), after which the tourniquet should be deflated for at least 10-15 minutes to allow tissue reperfusion before reinflation to minimize ischemic injury to muscle, nerve, and skin; longer tourniquet times are associated with increased risk of postoperative tourniquet paralysis, compartment syndrome, rhabdomyolysis, skin injury, and post-op pain.
How It's Used on the Ward
"Tourniquet time" or "under the tourniquet" — the duration the cuff has been inflated on the limb during orthopedic, hand, or extremity surgery; surgical teams track this number closely because muscles and nerves tolerate ischemia only for so long; the circulating nurse calls it out loudly as it approaches the recommended limit so the surgeon can plan deflation/re-inflation.
Example
""54-year-old undergoing right total knee arthroplasty. Tourniquet inflated at 0920 at 300 mmHg on the right thigh. At 1100 (1h 40min under tourniquet), circulating nurse calls: "90-minute mark approaching." Surgeon plans deflation at 120 min total. At 1140, tourniquet deflated for 12 min, hemostasis achieved, tourniquet re-inflated at 1152 for another 30 min to complete closure. Total tourniquet time: 2h 10min across two intervals. Tolerated without post-op neurologic deficit.""
Clinical Context
Physiology: muscle ischemia begins within minutes and becomes irreversible after several hours; nerve dysfunction begins with compression (mechanical, not ischemic primarily) and can result in post-op tourniquet paralysis (usually transient, resolving in days to weeks). Pressure setting: typically 100 mmHg above systolic BP for upper extremity (usually 250-300 mmHg), 100-150 mmHg above systolic for lower extremity (usually 300-350 mmHg). Complications: (1) Post-tourniquet syndrome — limb swelling, stiffness, weakness after deflation (usually self-limited). (2) Tourniquet paralysis — nerve injury from prolonged compression. (3) Compartment syndrome — rarely, from reperfusion swelling. (4) Rhabdomyolysis — with very long times. (5) Skin injury — chemical burns from prep pooling under cuff, mechanical blisters. Safety practices: deflate at safe intervals, document cumulative time, never leave inflated for prolonged period during pauses in surgery, deflate prior to wound closure when feasible to allow hemostasis check.